Saccharomyces

Saccharomyces is a genus of fungus including many species. The distinct species of Saccharomyces are revised frequently as more research is done. All species are unicellular and capable of fermentation. Saccharomyces cerevisiae is the most well-known species of yeast. It is used in the fermentation of beer, wine, and sake, and as a leavening agent in bread. It is commonly referred to as "ale yeast", "wine yeast" (see Killer Wine Yeast below), or "bread yeast". S. pastorianus, known as lager yeast, is a hybrid closely related to S. cerevisiae but is not a true species. S. cerevisiae is commonly studied as a model organism and was the first eukaryote to have its genome entirely sequenced. In rare cases, Saccharomyces can form a pellicle.

See Lactobacillus, Pediococcus, Brettanomyces, Mixed Cultures, Kveik, and Nonconventional Yeasts and Bacteria charts for other commercially available cultures.

Genus

The origin of S. cerevisiae and other species of Saccharomyces, as well as the entire genus itself, is likely to be Asia, according to genomic studies. The presence of ancestral polymorphism (variations on the same genetic sequence between populations) suggests that these species arose during a short period of time during which a lot of genetic inheritance was shared before the speciation events occurred. Despite this, genetic differentiation between species of Saccharomyces is higher than in plants and animals .

Some species could have originated in other parts of the world. For example, S. uvarum and S. eubayanus in South America, S. jurei and S. paradoxus in Europe, and S. arboricola in Oceana . These speciation events occurred around 5-10 million years ago during the warm climate of the Miocene ephoc. Humans played a particularly important role in the genetic divergence of some strains of S. cerevisiae (see History of Domestication below).

See also:

• Saccharomyces at Wikipedia.
• ScienceDirect AI generated topic article.

Species

Saccharomyces cerevisiae is the type species of the genus Saccharomyces, and is well-known and highly studied. it is used in industrial production of baking and fermentation as well as bioenergy and biomedical fields. Wholke-genome sequencing was completed in 1996, and since then the body of scientific knowledge on the species of S. cerevisiae is higher than any other eukaryotic system. More recently, whole-genome sequencing has also been performed on other species of Saccharomyces, which has resulted in models for studies on population genomics, as well as insight into the evolution of this genus .

Species of Saccharomyces other than S. cerevisiae (and only certain strains of S. cerevisiae) are generally unable to efficiently ferment maltotriose, although some can ferment maltose (such as S. eubayanus) .

Species	Ecology	Notes
S. cerevisiae	Domestic: Beer, Wine, Bread. Wild: Ripe fruits.	Believed to have been originally isolated from the skin of grapes
S. pastorianus	Lager-type Beer Fermentation.	Lager yeast; hybrid of S. eubayanus and S. cerevisiae
S. paradoxus	Deciduous trees (oak, maple, birch)	Closest known species to the baker's yeast
S. eubayanus	Patagonia	Probable parent of lager yeast
S. mikatae	Decayed leaves in Japan
S. kudriavzevii	Decayed leaves in Japan	Involved in hybrid strains used in commercial brewing and winemaking strains with S.uvarum, S.cerevisiae and S.bayanus.
S. bayanus	Wine	Hybrid of S. uvarum, S. eubayanus, and S. cerevisiae. Once proposed to be the parent of S. pastorianus, although this is no longer the consensus. Most wine making strains sold as S. baynus have been found to be S. cerevisiae instead .
S. florentinus	Drosophila and sulphurized grape must
S. arboricola	Cold tolerant	Produces high levels of ethyl esters
S. uvarum	Found in nature and fermented drinks, especially cold fermentated drinks .	Contains horizontal gene transfers from S. cerevisiae and S. kudriavzevii due to human-controlled beverage fermentation .
S. jurei	Tolerant of cooler fermentation temperatures; discovered on oak tree bark (Quercus robur) in France.	Tolerant of high osmotic stress and high sugar concentrations. Discovered by Naseeb et al., 2017; 2018 .
S. bayanus	Found only in brewing environments	A complex hybrid between S. eubayanus, S. uvarum, and S. cerevisiae .

See also:

• Brewing Efficacy of Non-Conventional Saccharomyces Non-Cerevisiae Yeasts; 2021.

S. cerevisiae

General Info

• Escarpment Labs video presentations on yeast basics and Why do yeast cells need oxygen? | Yeast Basics 2: Lecture 1.
• Escarpment Labs blog post on FAN requirements for different strains of brewers yeast.
• "Yeast Micronutrient and Growth Factor Requirements," by Novozymes North America Technical Service - Bioenergy.
• MTF thread on using olive oil instead of oxygen for yeast growth, with link to New Belgium study and input from Lance Shaner.

Native Environment

Although it has been long understood that S. cerevisiae occurs naturally on bark and fruit , recent studies suggest that some Saccharomyces species are more abundant in leaf matter on the ground. See the "Where (Do) the Wild Yeast Roam" video by Bryan from Sui Generis blog and these studies/discussions:

• A systematic forest survey showing an association of Saccharomyces paradoxus with oak leaf litter.
• The interaction of Saccharomyces paradoxus with its natural competitors on oak bark.
• The natural ecology of Saccharomyces yeasts.
• Associated MTF thread.

Geographically speaking, studies such as Peris et al (2023) have used DNA sequencing to determine that many species of Saccharomyces originated in East Asia .

History of Domestication

• "The Yeast Family Tree Grows," by Lars Marius Garshol, 10-26-2021.
• Domestication and Divergence of Saccharomyces cerevisiae Beer Yeasts, by Gallone et al (2016); the first look at the domesticated S. ceresiae family tree and the grouping of two major genetic groups for domesticated ale yeasts: Beer 1 and Beer 2.
  • "A family tree for brewer's yeast" a review of a study on the family tree of brewer's yeast by Lars Garshol. See also Lars's write up on the history of people reusing yeast as opposed to spontaneously fermenting.
• Kristoffer Krogerus's attempts to map the Gallone et al. codes to the commercial White Labs/Wyeast products and updated family tree dendrograms:
  • Kristoffer Krogerus's attempt to decode the strains in the above mentioned study ("Domestication and Divergence of Saccharomyces cerevisiae Beer Yeasts") and a redraw of the dendrogram family tree of ale yeasts as well as a spreadsheet that makes a best guess to map the strains in the study to actual White Labs strains.
  • First update to the family tree of all of the yeast strains in the previously mentioned studies with commercial product names, by Kristoffer Krogerus.
  • Second update to the family tree which includes kveik sequencing from Tyrawa et al (2018), as well as discussing strains that might be the same from different yeast labs.
  • See also comments by Krisoffer on this MTF thread.
• Subsequent whole genome sequencing studies that grow the family tree of S. cerevisiae:
  • Distinct Domestication Trajectories in Top-Fermenting Beer Yeasts and Wine Yeasts, by Gonçalves et al (2016).
  • The origin and adaptive evolution of domesticated populations of yeast from Far East Asia, by Duan et al (2018); a study showing evidence for initial domestication of yeast in the Far East Asia.
  • Genome evolution across 1,011 Saccharomyces cerevisiae isolates, by Peter et al (2018), which indicated that domestication of yeast might have begun in Asia. See also this article and the associated MTF thread.
  • A yeast living ancestor reveals the origin of genomic introgressions. From Dr. Bryan Heit: "This study may interest some here. A lot of yeast evolution is driven by introgression - interspecies hybridization which gets "cleaned up" by back-crosses with one of the parental species (but leaving pieces of the other parental species genome behind). But it's always been a bit of a mystery of how these hybrids can back-cross, since these hybrids are usually unable to reproduce sexually. These scientists found a living ancestor of a hybrid between S. cerevisiae and S. paradoxus that gave rise to many modern S. cerevisiae strains, and may have figured out how it regained the ability to reproduce with its parental species ."
  • Modern beer yeast emerged from mix of European grape wine, Asian rice wine yeast, by Science Daily. The two explanations of beer yeast ancestry are: beer yeasts might have evolved from a mix of European wine strains and Asian fermentation strains during trade on the Silk Route, as well as an unknown ancestor. The second explanation is that European wine strains themselves descended from Asian strains (whether European wine strains descended from Asia or were developed in Europe has not been clear and needs more research).
  • Norwegian "kveik" yeast forms its own genetic group of yeast, indicating a subtree of the Beer 1 group.
  • Fermentation innovation through complex hybridization of wild and domesticated yeasts - Hittinger lab sequencing of commercial and homebrew strains of yeast, analyzing their hybrid species makeup using WGS.
  • BREWING YEAST FAMILY TREE (OCT 2019 UPDATE) Kristoffer Krogerus' updated family tree including the Hittinger WGS data.
  • "Domestication reprogrammed the budding yeast life cycle," De Chiara et al (2020).
  • Genome analysis of 1800 isolates from all Saccharomyces species by Peris et al. (2023) found that domesticated strains of S. cerevisiae displayed a higher rate of admixture (occurs when distinct lineages mix to create new genetic lineages) .
  • Whole genome sequencing of European farmhouse strains from Norway, Latvia, and Lithuania show that European farmhouse yeasts form their own group with ancestry from the Beer 1 group and domesticated yeast from Asia (note that Belgian saison strains are not included in this group and are contained within the Beer 2 group). See this study by Preiss et al. 2024 and this layman's summary blog post by Lars Marius Garshol. See landrace for more information about European farmhouse landrace yeast.
• Guinness yeast strains form their own mosaic (distinct genetic grouping) that is different than other Irish brewing strains (which are closely related to British brewing strains). Their closest related yeast is a Belgian ale strain that was used for "lagers" and was originally misidentified as lager yeast. The authors of the study that discovered this suggest that this Belgian strain originated from Dublin brewers. The two currently used Guinness yeast strains are very closely related to the original strains that were originally banked by Guinness: the 1903 Watling Laboratory Guinness yeast . See also this MTF post.

See also:

• YouTube presentation by Kevin Verstrepen:

• Stijn Mertens and Jan Steensels talk about their work on the MBAA podcast.
• Genome searches and strain publication searches (see this example).
• Media stories of "ancient yeast" supposedly being revived:
  • MTF discussion on a claim that a 4500 year old yeast was recovered from Egyptian pottery.
• Modern brewing yeasts continue to adapt to the modern brewing environment as the brewing methods change from yeast lab propagation and serial re-pitching: "Genomic stability and adaptation of beer brewing yeasts during serial repitching in the brewery".

• MTF thread by Dr. Bryan Heit provides a summary of "Phenotypic and molecular evolution across 10,000 generations in laboratory budding yeast populations"

Killer Wine Yeast

Many wine yeast strains are known to be "killer" yeast strains that produce toxins that kill nearby yeast cells in order to give the killer yeast strains a competitive edge over sensitive strains (the term for these toxins has been changed to "zymocides" in science , but is also sometimes called "mycocins" or "zymocins" ). Unwanted killer strains of Saccharomyces have been suspected to cause stuck wine fermentations by killing off the sensitive wine strain that was pitched into the wine by the winemaker . In Saccharomyces, killer strains are genetically determined to secrete toxins (in the form of extracellular proteins or glycoproteins) that kill sensitive strains (there is no evidence that these toxins affect humans). These killer strains are immune to their own toxin. The mycocin toxins can act on sensitive strains in a number of ways: by blocking DNA synthesis and preventing cell division, inhibiting the synthesis of beta-glucans (β-1,6-glucan) that a part of their cell wall formation, and by causing ions to leak through the cell wall. In low dosages, which is typical in the natural environment, toxin triggers active cell death (apoptosis), while large dosages cause necrotic cell killing (necrosis). One study in wine found that the use of killer strains to outcompete sensitive strains resulted in off-flavors from yeast autolysis . Another study found that a lager strain that was genetically modified to secrete killer toxins was able to eliminate all cells of a sensitive ale strain within 24 hours of beer fermentation at a pitching rate of 99% sensitive ale strain to 1% killer lager strain, indicating that even a small amount of killer cells can be enough to kill a larger population of sensitive cells . Ratios of killer cells to sensitive cells that have shown to completely eliminate or nearly eliminate the sensitive population on lab media includes 1:1, 1;10, and 1:100. In a starter of a sensitive strain that had 10% cells of a killer strain introduced, the viability of the sensitive strain was greatly reduced . Neutral strains do not produce toxins, nor are they killed by them . Almost all domesticated ale and lager strains are sensitive to the toxins produced by killer strains .

In Saccharomyces cerevisiae, four toxins have been identified: K1, K2, K28, and Klus, the first three of which can only kill other strains/species of Saccharomyces. The Klus toxin has been found to kill all strains of S. cerevisiae (including those that produce the previous three toxins), as well as yeast from other genera, such as Hanseniaspora spp., Kluyveromyces lactis, Candida albicans, Candida dubliniensis, Candida kefir and Candida tropicalis. Rodriguez et al. (2011) reported that out of 1,114 strains of S. cerevisiae isolated from spontaneous wine fermentations, 38% of them were killer positive with most producing K2. Only 7% of produced the Klus toxin (no commercial wine yeast strains have been reported to produce the Klus toxin that we know of) . The K1 toxin is most active between a pH of 4.6 and 4.8, while K2 and Klus are active around a pH of 4.0 to 4.3 . The activity of the toxin is greatest during the log phase of growth, and decays during the stationary phase of fermentation . Generally, none of the toxins secreted by killer strains of Saccharomyces have been found to kill Brettanomyces . One study from India reported that a wild S. cerevisiae strain caught from flowers killed another wild caught strain of Brettanoyces anomulus, however, their methodology was not explicit and potentially not scientifically rigorous enough . For example, this study did not use DNA fingerprinting to identify the wild yeast strains used in the study and instead relied on morphology and media selection, and they did not identify the type of toxin produced by the killer strain of wild S. cerevisiae. They also reported that the B. anamulus strain did not ferment glucose, which is not typical for this species and indicates that it might have been misidentified.

Several strains of Saccharomyces eubayanus isolated from seeds from monkey puzzle trees in Patagonia, Argentina, were found to secrete a killer toxin that kills Brettanomyces and Pichia. One strain was found to produce a lot of the toxin, which is called "SeKT". S. cerervisiae strains, including strains that are sensitive to the above toxins, are not sensitive to this toxin. Mazzucco et al. (2019) found that SeKT toxin produced by this one strain of S. eubaynus in a special growth medium designed to maximize the SeKT toxin production (WUJ medium, which is "ultrafiltered" apple and pear juice) inhibited a strain of B. bruxellensis to around 50% growth after 48 hours in a wine growth medium. It also inhibited Pichia guilliermondii, Pichia manshurica, and Pichia membranifaciens by 50-70%. Note that the toxin was applied directly to the Brettanomyces and Pichia species, and not in a co-fermentation setting. Since S. cerevisiae strains are not effected by the SeKT toxin, it has been proposed as a way to limit Brettanomyces and Pichia in wine fermentations .

Various other yeast species have the ability to produce toxins that effect a range of other yeasts (but generally not bacteria), including species from the genera Candida, Cryptococcus, Debaryomyces, Hanseniaspora, Hansenula, Kluyveromyces, Metschnikowia, Pichia, Ustilago, Torulopsis, Williopsis, Zygosaccharomyces, Aureobasidium, Zygowilliopsis, and Mrakia . For example, strains of the yeast species Candida pyralidae , Wickerhamomyces anomalus, Kluyveromyces wickeramii, Torulaspora delbrueckii and Pichia membranifaciens have been found to produce toxin that inhibits Brettanomyces . In addition, the toxin produced by Wickerhamomyces anomalus and Williopsis markii have been found to inhibit a wide range of spoilage and pathogenic fungi . Killer strains of S. cerevisiae and other yeast can occur naturally in the wild on fruit and can have a negative impact on other flora that are found in the same environment . Strains of Torulaspora delbrueckii have been shown to kill killer strains of S. cerevisae (wine strains), as well as to kill Pichia species . The occurrence of killer strains of yeast in the wild is also wide spread. For example, out of 210 yeasts from various genera isolated from molasses, 13 of them were killer strains. Out of 1,000 isolates of various Candida species isolated from human skin, 52 were killer strains. Out of 65 strains of various yeasts isolated from fermented foods, soil samples, and spoiled fruits/vegetables, 12 were killer strains . It has been hypothesized that toxin production is ubiquitous throughout nearly all genera of yeast; the more studies that have been done on a particular genus of yeast, the more likely it is that toxin production has been found by species and strains within that genus. Yeasts that produce toxins have been found on every continent and in every natural habitat of yeast, including leaf surfaces, leaf litter, tree slime fluxes, fruits, cactus stems and cladodes, insect guts, mammal feces, leaf-cutting ant nests, lake water, ocean sediment, soil, wine, bakeries, and dairy products .

A newly discovered toxin that is related to the K1 toxin, called "K1-like" or K1L, has been identified in Saccharomyces paradoxus. The ability for this species to produce this toxin is caused by a virus that binds to the DNA of the yeast cells, and spread via horizontal gene transfer. The K1L toxin has a pH optimum mostly between 4.5 and 5, with no inhibitory activity at pH 5.5. It is denatured at a temperature of 98°C. A screening of this genetic change, called “K1-like Killer Toxin” (KKT) genes, in other yeasts showed that many other species can also produce toxins similar to the K1L toxin but slightly different in effect, including Kazachstania africana, Naumovozyma castellii, Naumovozyma dairenensis, Tetrapisispora phaffii, and Pichia membranifaciens. Each of the identified species could kill at least one other type of yeast with its toxin, and was immune to its own toxin, but susceptible to other K1-like toxins from other yeast species. Differences in the production of these K1-like toxins between 5 different strains of P. membranifaciens indicated that the toxins can be strain-specific, rather than species-specific. Using the genetic relatedness between the different KKT genes, the researchers concluded that this family of K1-like toxins originated outside of the Saccharomyces genus. This research uncovered a new family of K1-like antifungal killer toxins amoung many species of yeast in the Saccharomycotina subphylum .

Scientists have used genetic modification to create S. cerevisiae strains that produce various killer toxins that can assist in completing fermentation in the baking, wine, distillation, and beer making processes. These yeasts are able to inhibit undesired yeast contaminants, preventing various off-flavors and other unwanted characteristics in the finished products. Ale and lager strains that have been modified to release these toxins have reportedly retained the positive fermentation and flavor characteristics of the original strains . Branco et al. (2017 and 2019) discovered several strains of S. cerevisiae that excrete a biocin toxin that is active against several other genera of yeast, including Brettanomyces bruxellensis. The toxin is composed of peptides derived from the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH), which is a protein that serves many different roles in different species of microbes and animals. This toxin is produced by some strains of S. cerevisiae as they enter the stationary phase after primary fermentation. However, the amount of the toxin needed to inhibit B. bruxellensis was 10 times the amount that is produced naturally during fermentation. The researchers later genetically modified a strain of S. cerevisiae to over-produce the toxin, which they named "saccharomycin", at levels required to completely inhibit B. bruxellensis when co-pitched at a 1:1 ratio (10^5 cells/ml for both). This toxin was also reported to be highly active against Hanseniaspora guilliermondii, Kluyveromyces marxianus, Lactobacillus thermotolerans (inhibited at 250 μg/ml of toxin), while inhibition of Torulaspora delbrueckii and B. bruxellensis required very high amounts of the toxin (500 μg/ml and 1000-2000 μg/ml) . They later demonstrated that using 1.0 mg/mL of saccharomycin with 25 mg/L of SO₂ in grape must fermentation completely eliminated B. bruxellensis .

See also:

• None of the wine yeast strains from White Labs are killer positive, according to Kara Taylor, White Labs Senior Lab Manager.
• Bryan Heit's simple method for testing for killer sensitivity using nothing more than agar plates.
• List of killer strains as well as phenol production (4VG and 4VP) in various wine yeasts, compiled from a scientific study Hisamoto et al. (2010).
• For the implications of this on re-yeasting beer with wine yeast at packaging, see the Packaging page.
• For concerns about using bottle dregs from commercial sour beers that are bottled with wine or champagne yeast, see Commercial Sour Beer Dregs.
• Lallemand chart of wine yeasts and their Killer Factor.
• Another chart of wine yeast strain and killer factor (column labeled "Competitive Factor").
• Chris Lewis's write up on wine yeast character/Killer Factor on Lewy Brewing Blog.
• Shea Comfort notes on wine yeast on the BBB.
• "Brewing With Wine Yeasts" by Michael Tonsmeire". See also Dara McMains's MTF thread on beer fermentation with wine yeast and Brettanomyces.
• "Brewing Beer with Wine Yeast," by Neil Playfoot, Asian Beer Network.

To do: https://www.researchgate.net/publication/317177883_Biology_of_Killer_Yeast_and_Technological_Implications

Using Killer Yeast to Inhibit Diastatic Yeast

It has been demonstrated that various toxins produced by "killer" strains of S. cerevisiae can be used to inhibit most strains of diastatic strains of S. cerevisiae. Certain strains of diastatic S. cerevisiae are sensitive to one or more of these toxins. One study showed that adding K1 and/or K2 toxin could reduce the risk of a diastatic yeast contamination in breweries .

See also:

• WBC 2020 Presentation "Can we rescue Beer infected with Diastaticus during fermentation: A profile in killer yeast and the effect of co-fermentation on the superattenuative characteristics of diastaticus."
• MBAA Podcast episode 193 with Nicholas Ketchum, "Could beer infected with diastaticus be rescued by killer yeast?"
• MTF post on using CBC-1 killer positive to limit primary yeast.
• All About Beer article, "Attack of the Killer Yeasts: A Groundbreaking Solution for Craft Brewers".

Autotoxin

- https://journals.plos.org/plosbiology/article?id=10.1371%252Fjournal.pbio.3001844

Diastatic strains of Saccharomyces cerevisiae

Do a page search (CTRL+F) on this wiki page for the term "diastatic" or "diastaticus" to see all of the confirmed or suspected diasatic strains listed in the commercial culture charts below.

Another list is available here from Craft Labs.

Diastatic strains of Saccharomyces cerevisiae, historically designated as a variant of S. cerevisiae (Saccharomyces cerevisiae var. diastaticus), is a group of S. cerevisiae strains that can ferment certain types of starches and dextrins, and has been identified as a contaminant in breweries and is responsible for a few large recalls. The variant based nomenclature has been called into question (classifying it as a true variant based on one phenotype is not typical in microbiology), and terms like "STA1+ strains of S. cerevisiae" or "diastatic cerevisiae" have been proposed as a more scientifically correct designation . These strains generally do not produce flavors that are considered unpleasant. For example, acetaldehyde and sulfur dioxide are produced in very low amounts compared to other brewing strains. With the exception of a few strains, such as the "Sacch Trois" strain, most diastatic cerevisiae strains also produce phenols (POF+), which are considered off-flavors in many beer styles other than Belgian ale styles and German Hefeweizen (there is no genetic link between POF+ and STA1 genes, and the link may just be coincidental due to human selection). Most strains also produced significant amounts of isoamyl acetate (banana ester) and other fruity esters, making them taste very similar to German wheat strains. A small number of strains also produce above flavor threshold levels of diacetyl . This variant is often viewed as a contaminant because of its ability to over-attenuate. A survey of contamination reports in the last ten years at European breweries (50% of which were German breweries, which are obligated by law to report such contaminations) found an increase in reports from 2015, 2016, and 2017. 71% of the contamination incidents originated from the packaging systems (bottling/canning lines). These contaminations were tracked down to the filler environment and/or biofilms in the pipework system of the filler which stemmed from hygienic problems. As such, sometimes contamination can be sporadic with some bottles being contaminated while others are not. The other 29% of the contaminations were tracked down to primary contaminations in the brewhouse, fermentation cellar, and storage cellar .

STA1+ strains of S. cerevisiae can produce extracellular glucoamylase (also called alpha-glucosidase, which is the same enzyme that Brettanomyces produces to break down starches and dextrins). This enzyme is released outside of the cell and can break down the α-1,4 linkages of starches and dextrins releasing glucose that is then fermented by the yeast. The capability to produce this enzyme is encoded by the STA1 gene, which is a fusion of two other genes that are present separately in all S. cerevisiae yeasts, FLO11 and SGA1 (the STA2 and STA3 genes are the same as STA1; they were initially found on different chromosomes and so they received different names, but they are all the same gene ). Not all strains containing one of these genes produce the glucoamylase enzyme or are as effective as others at metabolizing dextrins . It has been reported by some microbiologists that most brewing strains that contain the STA1 gene do produce the glucoamylase enzyme (~16 mins). A study that surveyed 18 strains of S. cerevisiae that contain the STA1 gene found that only one was not able to ferment dextrins . Richard Preiss has also reported that WLP351 has the STA1 gene, but is not able to ferment dextrins . Krogerus et al. (2019) discovered that a region of 1162 base pairs just upstream of the STA1 gene called "a promoter gene" is missing in strains that test positive for the STA1 gene but do not test positive for fermenting starches, dextrins, or secreting the enzyme. They were able to demonstrate that this promoter gene region is needed for the STA1 gene to become expressed. They also discovered that STA1 gene is found in the Beer 2 group of yeast (see History of Domestication above), and wild S. cerevisiae strains do not carry the STA1 gene. Coincidentally, Beer 2 yeast strains lack the genes that the Beer 1 yeast strains do for fermenting maltotriose, yet Beer 2 yeasts ferment maltotriose just fine; it was discovered by Krogerus et al. (2019) that the STA1 gene allows the Beer 2 yeasts to ferment maltotriose (although this exact mechanism is not known yet). It was proposed that the STA1 gene evolved in the Beer 2 yeast strains as a means to take advantage of grain fermentation as an evolutionary advantage, and the existence of strains that are missing the promoter gene could be because humans later started selecting for strains that didn't dry the beer out too much . For more details on the Krogerus et al. (2019) study, see this Suregork Loves Beer blog post and this MTF thread posted by Kristoffer Krogerus.

When beer containing this yeast is packaged too early, it will continue to slowly ferment dextrins and cause over-carbonation. When pitching a proper cell count or pitching rate of a diastatic yeast strain into the wort, some strains will fully ferment as quickly or nearly as quickly as any other brewers yeast, while other strains may take as long as 16 days to fully ferment a simple 12.4°P (1.050 SG) wort. A highly dextrinous wort may take longer to fully ferment. The problem of slow fermentation in already packaged beer is usually only a concern when diastatic cerevisiae is introduced as a very small cell count, for example as an accidental contamination . The enzyme produced by these strains is heat stable and can continue to work on starches and dextrins even after the yeast is killed by heat pasteurization . Almost all diastatic strains of S. cerevisiae are able to ulilize all of the sugars found in wort (e.g. glucose, fructose, sucrose, maltose, maltotriose), although one strain tested in a recent study could not efficiently ferment starch, maltose, (80%) or maltotriose (45%) . STA1+ strains of S. cerevisiae can grow at 37°C and can also remain viable at refrigeration temperatures . Some strains of diastatic cerevisiae are as flocculant as typical ale strains, while others are less flocculant . One strain of diastatic cerevisiae, the Belle Saison strain from Lallemand, is killer neutral, which means that killer wine strains will not kill it (it is not verified if Belle Saison is the same as WY3711, although it is suspected to be). Other strains of diastatic cerevisiae may or may not be killer neutral (more data is needed; see killer wine strains for more information on this topic).

Diastatic cerevisiae contamination in breweries has been a recent hot topic. These strains are effectively eliminated by standard cleaning and sanitation practices, although inadequate cleaning hygiene can lead to biofilm formation which makes them more resistant to cleaning regiments . The source of some contaminations has also been suspected to potentially come from yeast suppliers, although there is no known percentage of infections which originate from yeast suppliers versus poor hygiene in the brewery. For example, a lawsuit by Left Hand Brewing Co. accused White Labs as being the source for the brewery's diastatic yeast contamination issues (see also this statement by White Labs) . Detection of STA1+ strains of S. cerevisiae as a contaminant can be difficult (see "Detection Methods" below). Contamination usually occurs as a secondary contaminant (meaning in the packaging system), and can come from contact with beer lines, by air circulation in the area of the packaging equipment, or by insufficient heat treatment of the packaging line. Since one viable cell that is able to divide can be enough to contaminate beer, contaminations can be sporadic with only a percentage of bottles being contaminated . Documented attenuation percentages above 75% for any strain of S. cerevisiae is also an indicator that the strain could be diastatic, however, some non-diastatic strains can also attenuate higher than 75%, so this indicator is not a reliable method to be sure that a given strain is STA1+ . Often this contamination can only be detected by sensory testing weeks after packaging.

Detection Methods

This yeast can been detected using LCSM agar plates, although other species of wild Saccharomyces yeast can grow on this media (~18 mins) and PCR DNA analysis is required to give a positive identification of STA1+ strains of S. cerevisiae. Additionally, the default level of CuSO₄ which is ~550 ppm (this can vary depending on manufacturer) can inhibit some strains of diastatic cerevisiae; Wade Begrow of Founders Brewing Co. recommends diluting the LCSM media with a basic malt media so that the CuSO₄ reaches around 200 ppm, or using LCSM plates modified with a gradient of CuSO₄ (~22 mins in). Adding p-coumaric acid or other cinnamic acids to the LCSM agar media which can then test for POF+ yeast and then confirmed for the presence of phenols via a gas chromatography or some other method can also be used to indicate that a yeast might be STA1+ since most strains produce phenols from these cinnamic acids (see also this MTF thread on using cinnamic acids to identify phenolic off flavor strains).

Cheaper methods of doing PCR are recently becoming available, and could help breweries with smaller budgets sufficiently detect this as a contaminant (see PCR Lab Techniques). A recent study used agar plates with 15 g/L^-1 of starch as the only nutrient with 40 mg/L^-1 bromophenol blue in anaerobic conditions to detect the fermentation of starch (a pH drop from 5.2 to 4.6-3.0 will change the color of the agar plate to blue/violet). For some of the slower growing strains, 14 days were required to verify that they were STA1+ while other strains grew as quickly as two days and most strains grew after five days. The yeast cells had to be thoroughly washed of all other carbohydrate material and starved in order to avoid false positives. Using dextrin agar plates instead of starch also led to false positives . Note that diastatic S. cerevisiae cells look the same under a microscope as regular S. cerevisiae, so cell morphology is not an effective way to identify STA1+ strains (~8 minutes in). Other methods of detection include using a Durham tube/fermentation tube test to see if the beer produces CO² after fermentation, although this method does not identify the cause of the additional fermentation (~18 mins in). More recently, Krogerus et al. (2019) developed more precise PCR primers to detect STA1 active, STA1 non-active, and non-STA1 based on their discovered role of an STA1 promoter called 1162 bp that is required for the STA1 gene to be effective at producing the glucoamylase enzyme, however, PCR and qPCR have limited detection rates of 10^-4 and 10^-5 cells (see this Suregork Loves Beer blog post and this MTF thread posted by Kristoffer Krogerus).

Detection of STA1+ strains of S. cerevisiae as a contaminant can be difficult. While using PCR to detect the STA1 gene and the promoter gene, the presence of the promoter gene alone does not completely explain the wide variance of diastatic power between strains. Additionally, PCR genotyping is sucseptable to user error or DNA detection from dead cells. Detection of the presence of starch degrading enzymes can come from other contaminants such as Brettanomyces . Some agar media products and even starch/dextrin materials have been suspected to contain small amounts of glucose or other simple sugar contaminants that can support the growth of non-diastatic yeasts . Omega Yeast Labs reported that a slight alteration to the classic LCYM media recipe had significantly more reliable detection than classic LCYM and the proprietary Weber diastatic agar for all STA1+ strains in Omega's collection, including detecting slow growing strains within 2-3 days and strains with the non-active promoter genes as per Krogerus et al (2019) and limited false positives. See Saccharomyces agar plates for the recipe and this MTF thread by Laura Burns from Omega Yeast Labs, as well as their associated peer reviewed study on recommended detection methods) . A summary of the Omega Yeast Lab detection methodology findings by Lance Shaner is available here on MTF. Escarpment Labs built upon the work by Burns et al. and developed a modified version of the Omega LCYM, and they reported it to have less false positives for non-diastatic strains and it has reportedly been used for growing beer strains of Brettanomyces and Pichia. See the Escarpment SCCM media.

In 2022, Ida Uotila and Kristoffer Krogerus developed a simple detection technique that only requires basic lab equipment (pipettes, centrifuge, and heat block), gives results from beer or yeast samples in 75 minutes, and with accuracy as good as traditional PCR-based methods. The test result can be visualized on a lateral flow strip. For more information, see their published paper (associated MTF thread).

Commercial Strains

WY3711 saison yeast has been determined to be STA1+ . Since yeast cannot be patented, many yeast labs are thought to offer this strain to customers. In the commercial culture lists below where we believe a lab is selling this strain or another strain of diastatic yeast, we note that it is determined or suspected to be STA1+.

White Labs now reports that the strains WLP045, WLP073, WLP099, WLP545, WLP566, WLP570, WLP590, WLP644, WLP740, and WLP885 are potentially diastatic (thanks to "thcipriani's" python script), however, they do not designate if these strains actually ferment dextrins. Some hints as to which other White Labs products might also be diastatic have been deduced from the Gallone et al. study which published DNA sequencing on most of the yeast strains in the White Labs bank. However, the codes used in the Gallone paper for each strain of yeast were not defined as far as which White Labs products they correspond to. Some of the codes have been speculated on which White Labs strains they might refer to (see History of Domestication above). The strains from the Gallone paper that appear to contain STA1 are Beer002, Wine019, Beer092 and Beer059. The Beer059 code might correspond to WLP026 according to this speculative table, which has had reports of high attenuation and has been independently confirmed to be STA1+ by Kristoffer Krogerus (it is also only one of two known examples of a diastatic strain that are not also POF+; the other diastatic strain that is POF- is WLP644) . There has been a report by Richard Preiss of Escarpment Laboratories that WLP570 (confirmed by White Labs) and WLP585 both have the STA1 gene, but it takes weeks before they hyper-attenuate . Other yeast labs such as Lallemand, Inland Island, Escarpment Labs, and The Yeast Bay also list which strains they offer are diastatic.

See also:

• Dr. Bryan Heit of Sui Generis blog gives a layman video explaining the genetics of diastatic yeast.
• MTF "The Podcast" episode on STA1+ strains of S. cerevisiae with Kristoffer Krogerus and Richard Preiss.
• Kristoffer Krogerus explains his discovery of the STA1 promoter gene that explains why some STA1 positive strains do not effectively ferment starches or dextrins, as well as the occurence of this promoter gene within the Beer 2 yeast group and lack of it in wild yeast, new PCR primers for detecting active vs non-active STA1 strains.
• Escarpment Labs PCR protocol for testing for STA1, including details on the limitations of PCR testing and Part 2, identifying using starch agar plating and LCSM plating.
• Sui Generis Brewing blog articles on using practical methods of PCR to identify diastatic and other contamination for small breweries.
• This MTF thread on White labs lawsuit, identification via PCR and different agar media, and general contamination handling.
• ASBC "Rapid Methods for Detecting Saccharomyces diastaticus, a Beer Spoilage Yeast, Using the Polymerase Chain Reaction."
• Reddit thread on detecting diastatic cerevisiae.
• MBAA Podcast on diastaticus Part 1 and Part 2. Also Using FPDM media from Dr. Farber vs Weber, and issues with media getting too old after a day or two.
• MBAA webinar by Wade Begrow (free for MBAA members, $50 for non-members).
• MBAA Podcast Episode 193, "Killer Yeast" with Nicholas Ketchum on using killer yeast strains to kill diastatic yeast.
• Bru Lab Podcast, Episode 021 | Detection and Risk Assessment of Diastatic Yeast w/ Dr. Laura Burns.

Saccharomyces cerevisiae var boulardii

Although originally designed as a separate species (S. boulardii), it is actually a variety of S. cerevisiae and shares more than 99% of the genetic makeup of S cerevisiae . This strain is sold by East Coast Yeast in their ECY03 Farmhouse Blend and Bootleg Biology as their "Chardonnay" strain .

Genetic Engineering

• Lallemand SOURVISIAE® is GE California ale yeast based strain that produces lactic acid as a by product of fermentation. See also "Diving Deep In To Sourvisiae" by Dr. bryan Heit.
• Efficient breeding of industrial brewing yeast strains using CRISPR/Cas9-aided mating-type switching.

S. jurei

Newly discovered S. jurei was screened for use in beer, as well as hybrids between two strains of S. jurei and two strains of S. cerevisiae (Omega Labs OYL200 "Tropical IPA" and OYL500 Saisonstein). The hybrids were non-GMO type hybrids (natural mating). As expected, the hybrids were better at fermentation in wort (better utilization of maltose and maltotriose). The hybrids were reported to be "tropical and floral" from esters characterized by a combination of both parents, and one of the hybrids appeared to have lost the ability to produce phenols (4-vinyl guaiacol; clove) from the S. jurei parent .

S. ludwigii

Some species of this genus cannot ferment maltose or maltotriose, which make up the majority of sugar in brewer's wort. For example, Bellut et al. (2018) found that one strain that was isolated from kombucha could not ferment these complex sugars. This is due to the lack of a maltose transporter and the enzyme maltase. It also could not ferment melibiose, but could ferment glucose, fructose, sucrose, raffinose, and cellobiose. As such, they have been proposed as being potentially useful in non-alcoholic beer fermentation. Additionally, these species were able to grow in 7◦ Plato wort with a range of IBU (50 IBU was the maximum IBU tested), indicating that IBU's don't impact the growth of these species. They also lacked the ability to produce phenols. It was described as moderately flocculant, with the flocculation depending on the FLO gene and the presence of calcium in the wort (the same as Saccharomyces). They produced much less higher alcohols (n-propanol, isobutanol, and isoamyl alcohol) than the WLP001 control yeast, and fewer esters, and about the same amount of acetaldehyde and diacetyl than WLP001 .

S. thermantitonum

This species may not be genetically distinct from S. cerevisiae .

• MTF thread on S. Thermantitonum.

S. paradoxus

• "Saccharomyces species experiment #1: Paradoxus Ale," by Matt Humbard on A PhD in Beer Blog.
• Brewing potential of the wild yeast species Saccharomyces paradoxus.

S. eubayanus

Utilization of maltose by 10 strains of S. eubayanus; higher utilization corresponds with higher ethanol production. Figure 1C from Mardones et al (2020). Uploaded with permission from Kristoffer Krogerus.

Volatile compound production of interest in beer by 10 strains of S. eubayanus. Figure 1D from Mardones et al (2020). Uploaded with permission from Kristoffer Krogerus.

S.eubayanus is one of the probable parents of lager yeast (S. pastorianus) via the hybridisation with S. cerevisiae . It was first isolated and described in 2011 growing within Nothofagus trees in Patagonia, Argentina. Since then, strains of this species have also been found in cold regions across the globe, including Tibet, China, the United States, Chile, and New Zealand. It has also been isolated from the wild in Ireland . S. eubayanus has been described as being cold-tolerant, and can grow between 4–25°C. It has been suggested that this trait was inherited by lager yeast.

Although only a small number of strains have been collected from the wild by scientists, S. eubayanus has a wide range of genetic diversity between different strains. Some strains show potential for brewing purposes, which is primarily characterized by how well they ferment maltose. Mardones et al. (2020) evaluated 10 strains of S. eubayanus and their potential for fermenting wort. Four of the strains were isolated from Chile, four from Patagonia, one from Argentina, and one from New Zealand. All of the strains efficiently fermented glucose and fructose, while none fermented maltotriose. Maltose utilization varied greatly across all of the strains with the Argentinian strain (CBS-12357) utilizing maltose the most and producing the most ethanol. Overall, there was no correlation to how well strains fermented maltose based on what country they were from. There was also a wide range of esters, higher alcohols, and carbonyl compounds produced by the different strains. For example, two of the strains of Patagonia (CL465.1 and CL450.1) produced some higher alcohols and acetate esters like 2-phenyethyl acetate (rose, honey) and 3-methylbutyl acetate (banana), while other strains (Argentinian strain CBS-12357 and Chilean strain CL216.1) produced more ethyl octanoate and ethyl decanoate (fruity and apple-like). Nearly half the strains produced very low levels of all of the compounds measured. Most strains produced insignificant levels of acetaldehyde, except for two of the Chilean strains .

Two of the strains were selected to brew beer on a pilot brewery system. The strains selected were one from Villarrica, Chile (CL216.1) and one from Coyhaique, Patagonia (CL450.1). The beers started off at 15 °Plato all‐malt wort and were fermented at a temperature of 15°C. Fermentation was finished after 24 days due to the cooler fermentation temperature. This resulted in a 5.6% ABV and 5.1% ABV beers, demonstrating the difference in maltose utilization between the two strains. Maltose was consumed after 10 days of fermentation, demonstrating that this species ferments simple sugars first (glucose repression), similar to other species of Saccharomyces. Significant differences in esters and other volatile compounds were developed towards the end of fermentation, demonstrating that significant differences in flavor were developed after most of the sugars have been consumed. The Chilean strain showed a better fermentation profile and the production of greater levels of desirable esters. They also observed significant differences in each of the strains' ability to utilize different nitrogen and carbon sources, such as amino acids, which can account for the differences in flavor production . All of the strains tested also produced phenols (POF+), so these strains are probably not suitable for lager-style beers but could be suitable for saison and other Belgian style beers .

See also:

• Example beer made with eubayanus by Kris Krogerus: "Brewing With Saccharomyces eubayanus"

S. pastorianus

Commonly known as lager yeast to brewers, this yeast is a hybrid of S. eubayanus and S. cerevisiae . S. pastorianus is named after the first description by Max Reess in 1870 following his work with German breweries utilizing bottom-fermenting lager yeast, naming it originally after Louis Pasteur.

For a long time the origins of the hybrid were unknown and were postulated to be a hybrid between S. cerevisiae and S.uvarum, or S. cerevisiae and S.bayanus. Recent work eg. Libkind et al 2011 proved that the hybridisation was between S. eubayanus, which had been recently found in South America and S. cerevisiae . Further work points to a Tibetan lineage of S.eubayanus being the most likely from those discovered in the wild so far (see also this MTF post). It is hypothesized that the hybridization event occurred in a Bavarian brewery (Hofbräuhaus in Munich has been proposed as the most likely site for the hybridization event) in the 16th century by the chance interaction of S. eubayanus with ale yeast; however, an alternative hypothesis is that bottom-fermentation with S. eubayanus was in practice before lager yeast was created .

This species is separated into two main lineages, "Saaz" and "Frohberg". The two lineages are believed to have descended from different hybridization events between S. eubayanus and S. cerevisiae. The two lineages also have different genetic structure, with Frohberg types having two copies of each of the S. eubayanus and S. cerevisiae chromosomes (triploid), and Saaz types having one copy of the S. cerevisiae chromosomes and two copies of the S. eubayanus chromosomes (allotetraploid)

Emil Christian Hansen was the first in the world to isolate a single pure strain of S. pastorianus while he was working at the Carlsberg brewery, leading to its the synonymous classification name, S. carlbergensis. The type that Hansen isolated was a Saaz type, and it's believed that Saaz types are also prevalent in Bohemian / Czech S. pastorianus strains while German types are typically Frohberg. ([1] , [2] )

With recent whole genome sequencing data, it has been discovered that some strains of commercial yeast have been misidentified as either lager yeast or ale yeast. Ben Sykes reported that publicly available genetic data for an upcoming study indicates that WLP800, the Czech lager yeast from White Labs, is potentially S. cerevisiae (ale yeast). WLP029 German Ale/ Kölsch Yeast is potentially lager yeast.

WLP051 California V Ale yeast is also S. pastorianus. Recent gene sequencing / PCR work has led to it being re-classified as a S. pastorianus yeast, though it has been used successfully for American-style Ale production.

Laboratory hybridization between different strains of S. cerevisiae and S. eubayamus strains from Patagonia has created new lager strains that have better fitness under fermentation, better maltotriose/maltose utilization, and fermentation capacity. These new strains offer more options to brewers who want to brew with lager yeast .

See also:

• Kristoffer Krogerus presentation on the genetics and evolution of lager yeast, hosted by Escarpment Laboratories, 4/20/2020.
• "All pilsner yeast strains originate from a single yeast ancestor," by Delft University of Technology, summarizing the study by Salazar et al. (2019).
• MTF thread by Kristoffer Krogerus on how to use tetraploid interspecific hybrids to produce viable spores for designed lager yeast strain development, with a link to his peer reviewed article, 09/17/2021.
• "Yeast Research and Scaling Secrets," interview with Dan Carey by Doug Piper.

In Fermentation

(To do)

https://www.researchgate.net/publication/320686420_Physiology_ecology_and_industrial_applications_of_aroma_formation_in_yeast

Fermentation Under Low pH Conditions

Saccharomyces species and individual strains have a wide range of tolerance to low pH and lactic/acetic acid concentrations, which have been identified as stressors for yeast fermentation. For ideal fermentation conditions for S. cerevisiae, lactic acid should not exceed 0.8%, acetic acid should not exceed 0.5%, and wort should not fall below 4.0 pH. Since pH is on a log-based scale, even small differences in pH (especially below 3.5) can make a large impact on whether or not a given yeast strain is able to ferment. This obviously presents a challenge to brewers when Wort Souring or naturally carbonating with yeast for sour beers .

Yeast that fails to bottle condition sour beer may not be due to death of the cells. Rogers et al. published a study that found that yeast used to bottle condition a sour beer at Upland Brewing Co. was still ~80% viable after two weeks, but the surviving cells were small and unbudded, indicating that they ceased growing and entered the stationary phase. This effect has been referred to as "terminal acid shock" .

As stated previously, lactic acid and low pH are identified as stressors for yeast, and can affect their ability to carbonate sour beer. Some strains tested display an ability to grow in higher lactic acid concentrations, while others do not, but this does not indicate that they are able to bottle condition sour beer. For example, WLP001 and WY1056 do not grow well in YPD dosed with lactic acid, whereas Lallemand CBC-1 ("Cask & Bottle Conditioned Beer Yeast") can still grow at a pH of 3. WY2007 and WLP300 grow well in moderate levels of lactic acid, but not once the pH gets down to 3. WLP715 Champagne Yeast grows fine in a pH of 3 (although lag time is effected). However, despite being able to grow in YPD with lactic acid dosages, CBC-1 and WLP715 both failed to carbonate an 8% ABV sour beer that had a comparable pH to the pH of the YPD plus lactic acid mediums. It is suggested that this might be due to the combination of stress from high alcohol, acetic acid, low nutrients, low oxygen, and tannins from fruit. Re-hydrating dried yeast may also lead to difficulties carbonating acidic and high ABV (8%+) sour beer due to the stress of desiccation and re-hydration on the yeast .

Rogers et al. found an easy solution to carbonating low pH, high ABV beers by first acclimating the yeast to the sour beer. Growing the yeast in YPD plus lactic acid plus ethanol was not enough to acclimate the yeast and reliably carbonate a highly acidic, alcoholic (8% ABV) beer. However, by growing the yeast first in a blend of YPD that was diluted with the sour beer itself in a 1:1 ratio, they found that both CBC-1 and WLP715 were then able to carbonate the sour beer (WLP001, WY1056, WY2007, and WLP300 were not given this treatment). This was explained as exploiting the microbes' resilience and ability to adapt to many environmental conditions by "pre-adapting" the yeast to the harsh conditions of the sour beer . It has been speculated that brewers without access to YPD might be able to achieve similar results by growing the conditioning yeast in sour beer diluted with DME wort and yeast nutrients (Fermaid K and DAP, for example) .

A second study showed that a strain of S. cerevisiae was able to adapt and grow in a lab setting to increasing concentrations of lactic acid. After multiple generations and by slowly increasing the amount of lactic acid per generation, the researchers got the pH of the growth media (either raffinose or glucose plus lactic acid) all the way down to pH 2.8. At this low pH, the yeast began to use lactic acid as a food source. This might explain some anecdotal experiences by brewers who have seen the pH of kettle sour beers rise (more evidence is needed to confirm this hypothesis). The researchers found that the gene called ACE2 is likely to be associated with the ability to adapt to low pH conditions. It is also a gene that controls the expression level of other genes, and is also responsible for forming "snowflake-like" structures (multicellular clumps of genetically identical cells that stick together after budding ). The yeast strain began to form these "snowflake-like" clumps after being adapted to the low pH environment. Further work should be done to determine which strains of S. cerevisiae might be more easily adapted to low pH environments, or if possibly all strains of S. cerevisiae could be adapted to low pH environments over time .

See also:

• Lactic Acid
• Acid Shock Starters
• Wort Souring
• The Sour Hour interview with Dr. Matt Bochman
• "Biochemist finds solution to 'acid shock' in craft brewers' sour beer production", article on Phys.org.
• "Quick Sour, then what? Acid Tolerance of Brewer’s Yeast" by Michael Tonsmeire

Esters

• "Esters and Fusel Alcohols" by Scott Janish.
• "Understanding Esterification", Sour Beer Blog.
• Detailed biochemistry write up of what variables affect yeast derived esters, with links to a few scientific papers; MTF post by Cory Widmayer.

Phenolic Off Flavor Strains

Some strains of S. cerevisiae can convert the ferulic acid, which is found in malted barley and in wheat (malted wheat more so than raw wheat), into the phenol 4-vinyl guaiacol (4VG). 4VG is less toxic to microorganisms than the ferulic acid and other hydroxycinnamic acids. It gives a clove-like flavor to the beer. While most beer styles consider this an off-flavor, it is an important flavor component for certain styles of beer such as German Hefeweizen, saison, and some Belgian styles. Strains that convert ferulic acid into 4VG during fermentation are known as "phenolic off flavor positive" or "POF+" and are characteristic of wild Saccharomyces, bread yeast, and a small number of brewers yeast. Most strains of brewers yeast, however, were selected for not having this capability, and are known as "phenolic off flavor negative" or "POF-". POF+ strains require two enzymes: phenylacrylic acid decarboxylase (Pad1) and a ferulic acid decarboxylase (Fdc1). The Pad1 enzyme creates a precursor required for the Fdc1 enzyme to work, which then converts the ferulic acid into 4VG. These enzymes are dictated by the presence of the PAD1 and FDC1 genes respectively . Yeast produced phenolic/clove aromas tend to dominate over hop aromas in dry hopped beer .

Evidence, while sparse, shows that increased fermentation temperature can increase the concentration of phenols produced by S. cerevisiae yeast . In Brettanomyces, fermentation temperature can make small differences for some strains, but the differences are probably not large enough to detect during sensory testing (see Brettanomyces phenol production) . Schwarz et al. (2012) https://www.sciencedirect.com/science/article/pii/S0308814612006498

While most beer strains of S. cerevisiae are POF-, a survey of over 200 strains of S. cerevisiae showed that 81-95% of wine yeasts are POF+. It was also shown that 85-97% of wild strains of S. cerevisiae are POF+. Other genera of yeasts that tend to be POF+ include Rhodotorula, Candida, Cryptococcus, Pichia, Hansenula, and Brettanomyces .

See also:

• Phenols produced by Brettanomyces.
• Kristoffer Krogerus's blog article on removing POF gene from Saccharomyces hybrids.
• MTF thread on detecting POF+ on agar.

To do:

https://www.ncbi.nlm.nih.gov/m/pubmed/18038991/

https://www.sciencedirect.com/science/article/pii/S0308814607007844

Commercial Saison/Belgian Strains of Saccharomyces

In cooperation with Eric Bandauski .

Apex Cultures

Name	Source	Attenuation	Flocculation	Temp°F	Notes
Belgian Abbey (Belgian Beer)		75-85	Medium	60-75°F

BAC Yeast

Name	Source	Attenuation	Flocculation	Temp°F	Notes
BY122	Achouffe	72-76%	High	64-84	One of many great beer yeast to produce classic Belgian ales. Phenolics develop with increased fermentation temperatures, mild fruitiness and complex spicy character. Similar to WLP550 or WY3522.
BY124		77-83%	Low	65-77	French Saison yeast starter is a strain that enhances the use of spices and is extremely attenuative yet leaves an unexpected silky and rich mouthfeel in a very dry finished beer. Produces Saison or farmhouse-style beers that are highly aromatic with clean citrus esters. Expect peppery and spicy notes with no earthiness and low phenols. This strain enhances the use of spices and is extremely attenuative but leaves an unexpected silky and rich mouthfeel in a very dry finished beer. Similar to WY3711. Determined to be a diastatic strain of Saccharomyces cerevisiae .
BY125	Saison du Pont	76-80%	Low	70-85	Belgian Saison Classic farmhouse ale yeast. Very tart and dry on palate with mild fruit. Finishes crisp and mildly acidic. Benefits from elevated temperatures. Classic farmhouse ale yeast. Spicy and complex aromatics including bubble gum. Very tart and dry on palate with mild fruit. Finishes crisp and mildly acidic. Benefits from elevated fermentation temperatures. Usually slow to attenuate. Similar to WLP565 or WY3724.
BY126	Westmalle	75-80%	Medium	64-78	Trappist Big ABV strain is a robust top cropping beer yeast with phenolic character. Trappist Big ABV beer yeast has an alcohol tolerance to 12%. It's ideal for Bière de Garde, as it ferments dry with rich ester profile and a malty palate. Similar to WLP530 or WY3787.
BY128	Esen, Belgium (De Dolle)	72-76%	Medium	62-75	This versatile witbier yeast strain can be used in a variety of Belgian style ales. This strain produces a complex flavor profile dominated by spicy phenolics with low to moderate ester production. It is a great strain choice when you want a delicate clove profile not to be overshadowed by esters. It will ferment fairly dry with a slightly tart finish that compliments the use of oats, malted and unmalted wheat. This strain is a true top cropping yeast requiring full fermenter headspace of 33% A tart, slightly phenolic yeast capable of producing distinctive witbiers and grand cru-style ales alike. Alcohol tolerant. Similar to WY3942.

Bootleg Biology/Spot Yeast

Name	Source	Attenuation	Flocculation	Temp°F	Notes
BB22204 - S. arlingtonesis	Wild yeast starter jar in Arlington, VA	High	NA	60-70	This culture ferments extremely cleanly in the low 60’sF (Kölsch and Lager hybrids), and subtle fruity/citrus esters in the higher end of the Ale fermentation range (wheat-centric beers). May produce sulfur aromas during primary fermentation, but those will be eliminated within a couple weeks (allow longer aging if fermenting at lower temperatures). S. arlingtonesis is a higher attenuator than most ale strains, so adjustments made need to be made to grain bills or mash temperatures if a drier beer is not preferred.
BBX0104 – Saison Parfait: New World Saison Blend	A unique blend of previously unavailable commercially used Saison cultures.	90-100	Med-High	Normal to High Ale Temperatures	Saison Parfait is our New World Saison Blend, a new take on the modern saison yeast flavor and aroma profile. Saison Parfait pairs classic pepper & spice saison phenolics with prominent juicy fruit esters that evoke citrus and lemon peel, and a touch of banana for complexity. Even more unique, it finishes with a balanced, full-bodied and silky mouthfeel despite its high attenuation. Saison Parfait means the “Perfect Season”, and is our ode to the fall harvest season. A time for hard work and also celebration. The peasants of rural Flanders and Wallonia created the Saison, and what we now call Farmhouse beers, to drink for sustenance and merriment. Bruegel likely depicted the drinking of Saison beer in his classic paintings of rural country life, “The Harvesters” and “Peasant Wedding”.

Cellar Science

Name	Source	Attenuation	Flocculation	Temp°F	Notes
MONK Dry Beer Yeast		75-85	Medium	62-77°F	A classic Belgian yeast strain for producing clean, yet complex, Belgian style Blondes, Dubbels, Trippels, and Quads. Delicate fruit flavors with restrained phenolic character. STA-1 Negative.
SAISON Dry Beer Yeast		95%	Low	62-75°F	Produces complex Saison and Biere de Garde style beer. Mildly spicy phenolic flavors combine with fruit and hints of citrus. Leaves a soft malt body with a rich mouthfeel. Determined to be a diastatic strain of Saccharomyces cerevisiae.

Community Cultures Yeast Lab

Name	Source	Attenuation	Flocculation	Temp°F	Notes
TCL21 Ocotillo	Ocotillo plant in Big Bend, Texas	86-91	High	69-74	Suggested Use: Saison, Belgians, Farmhouse ales, Cider, Braggot, and wine. Determined to be a diastatic strain of Saccharomyces bayanus. Also POF+.
TCL22 Yucca	Torrey Yucca plant in Texas	73-78	Low	68-72	Determined to be a diastatic strain of Saccharomyces bayanus. POF+. Suggested Use: Witbier, Belgian Blond, Hefeweizen, Kristalweizen, Barrel aged beers.
TCL32 Chisos	Chisos Mountains, Texas	86-91	Low	65-72	Determined to be a diastatic strain of Saccharomyces bayanus. POF+. Suggested Use: Tripel, Belgians, Dubbels, Siason, Witbier, and farmhouse ales.
TCL25 Prickly Pear Blend	Big Bend, Texas	73-80	Med	67-73	Contains two strains of S. cerevisiae. Determined to be a diastatic strain of Saccharomyces cerevisiae. POF+. Suggested Use: American Pale Ale, IPAs, English pales, Hopped Sour (bacteria not provided), Gose.
TCL34 The Window	Prickly Pear Fruit in Big Bend, Texas	70-75	Med/High	66-72	Determined to be a diastatic strain of Saccharomyces cerevisiae. POF+. Suggested Use: Belgians, Weizens, Trappist ale, Dubbels, German ales, and Saisons.
TCL31 The Falls	Columbine in Cattail Falls, Texas	70-75	Low	62-72	Determined to be a diastatic strain of Saccharomyces bayanus. POF+. Suggested Use: Witbier, Sour Witbier, Apricot Witbier, Citrus Wit, Hefeweizen, Belgian Ales, Dubbels, Trappist, Trippel, Saisons.
TCL24 Buttercup	Rio Grande River, Texas	73-85	High	66-71	Determined to be a diastatic strain of Saccharomyces cerevisiae. POF+. Suggested Use: Belgians, Barley wine, Winterale, Scotch ale, Heavy Ales, Stouts, Porters.
TCLH1 Swallowtail	Swallowtail butterfly, Texas	76-81	Med/Low	69-75	Determined to be a diastatic strain of Saccharomyces cerevisiae. POF+.
TCL38 El Monte Manor	San Antonio, Texas	87-92	Med	66-72	STA1 negative and POF+ strain of S. cerevisiae. Suggested Use: IPA, Belgian Saison, Brett Saison, Nordic Ales, Altbier, Tripel, Belgian Blonde.
TCLJ1 Cenote Sac Actun	Cenote Sac Actun (fresh water cave), Texas	89-94	Med	68-72	Determined to be a diastatic strain of Saccharomyces cerevisiae. POF+. Suggested Use: East Coast IPA, New England IPA, English Ales, Irish Red Ale, Brown Ales.

Craft Cultures

Name	Source	Attenuation	Flocculation	Temp°F	Notes
CCYL113 - Belgian Saison Ale Yeast					This yeast strain contributes clove flavor and aroma to the finished product. Fruity aromas are also experienced. Commercial pitches only.
CCYL114 - Belgian Ale Yeast					To produce any great distinctive Belgian style beer, do ferment with the Belgian Ale Yeast. Flavors emanating from beer produced by this yeast are rich in both spice and phenols and are mildly fruity. Commercial pitches only.
CCYL115 - Trappist Ale Yeast					The Trappist Ale Yeast has a unique fruit and plum flavor and aromas. It performs well in high gravity brews. Commercial pitches only.
CCYL116 - Belgian Wit Ale Yeast					The original yeast used to produce Belgian Witbier and a variety of other Belgian style ales. Commercial pitches only.
CCYL120 - French Saison Ale Yeast					The French Saison Ale Yeast is a versatile strain that works great for Saison or Farmhouse and other Belgian style beers where aromatic (estery), peppery, spicy and citrusy flavors are desired. Might be a diastatic strain of Saccharomyces cerevisiae if this strain is the same as WY3711 . Commercial pitches only.
CCYL121 Abbey Ale Yeast					Used to produce Trappist, Belgian, Belgian doubles and triples This yeast contributes a fruity characteristics. Excellent alcohol tolerance for high gravity beers. Commercial pitches only.
CCY126 French Ale Yeast					Clean strain that complements malt flavor. Low to moderate esters, when fermentation temperature is below 70°F. Moderate plus ester character over 70°F. Low diacetyl production. Good yeast strain for Biere de Garde, blond, amber, brown ales, and specialty beers. Commercial pitches only.
CCYL128 - Belgian Saison Ale Yeast Blend					The Belgian Saison Ale Yeast Blend has some phenolic and clove-like flavor and aroma characteristic and fruitier esters than CCYL113. Ferments faster than CCYL113. Commercial pitches only.
CCYL129 - Eagle River Ale Yeast™					Michigan indigenous. The Eagle River Ale Yeast is the second in a series of indigenous Michigan strains. It was isolated from the shore of Lake Superior near Eagle River Michigan. This yeast will produce excellent Belgian style ales. This yeast is rich in both spice and phenols exhibits predominantly fruity esters, similar to a Belgian ale strain. Commercial pitches only.
CCYL130 - Keweenaw Ale Yeast™					Michigan indigenous. The Keweenaw Ale Yeast is the third in a series of indigenous Michigan yeast strains. This yeast was isolated in Michigan's Keweenaw Peninsula. It has prominent spicy phenolics and some fruity esters, very reminiscent of a Saison yeast. Commercial pitches only.
CCYL131 Belgian Wit Ale 2.0					Less Belgian-like phenolics than CCYL116 and more spicy. Will leave a bit more sweetness, and flocculation is higher than CCYL116. Use to produce Belgian Wit, spiced Ales, wheat Ales, and specialty Beers. Commercial pitches only.
CCYL134 Rock Cut Ale Yeast™					Michigan indigenous yeast coming soon. Commercial pitches only.
CCYL138 Rock Cut Ale Yeast II™					Michigan indigenous yeast coming soon. Commercial pitches only.

East Coast Yeast

Name	Source	Attenuation	Flocculation	Temp°F	Notes
ECY03 Farmhouse Blend					A saison blend (ECY08) with a wild isolate from a small producer of Saison. Can produce a funky and acidic farmhouse ale particularly when a secondary fermentable is added (i.e. priming sugar or fruit). The wild isolate, ECY03B, now identified as Saccharomyces boulardii - is a wild-type strain of Saccharomyces cerevisae. ​Commercial orders will also include a small pitch of ECY03B with the ECY03 primary pitch. Pitching the 03B during high krausen also produces the "wildness" quickly without aging long-term .​
ECY-03B Farmhouse	Fantome	80		70-84	Previously misidentified as Brettanomyces . Fruity and funky profile with some acidity gradually increasing over time. Aeration has more of a muted effect. Identified as Saccharomyces boulardii .
ECY08 Saison Brasserie	Several Strains	80+		75-85	Several saison yeast strains for both fruity and spicy characteristics accompanied with dryness. See also tasting notes from MTF members.
ECY14 Saison Single	Single Strain	76-78		75-82	Smooth, full farmhouse character with mild esters reminiscent of apple pie spice
ECY46 Farmhouse 2		80-84		76-82	An American farmhouse isolate (Saccharomyces cerevisae / boulardii) producing a pleasant tartness quickly upon fermentation (pH 4.0 - 4.1). Expect high attenuation, slight citrus esters and tartness .

Escarpment Laboratories

Name	Source	Attenuation	Flocculation	Temp°C	Notes
Ardennes Belgian Ale		72-80	Med-High	18.3-24.4	A very versatile and production-friendly Belgian ale yeast, producing balanced Belgian esters and spicy notes. One of the rare Belgian strains which flocculates relatively well, making repitching and/or cropping easier when compared to other Belgian yeasts. Alcohol tolerance: high .
Classic Witbier		72-78	Med-Low	19-24	Medium alcohol tolerance. A genera-defining Witbier strain, famous for balanced phenol and ester character with slight tartness that emphasizes wheat flavour
Dry Belgian Ale		85+	Med-Low	22-26	Obtained from an American producer of Belgian-style beers. This strain exhibits classic dry Belgian flavours, and displays an aggressive primary fermentation. We especially like this strain for Strong Golden, Tripel, and other Belgian-style beers. NOTE: This strain contains the STA1 gene, meaning it might be a diastatic strain of Saccharomyces cerevisiae (pending data on whether it actually ferments dextrins or not). Many industrial yeasts are diastatic, due to the desire for very high attenuation levels. However extra care must be taken to ensure these yeasts do not cross-contaminate non-diastatic yeasts. Contact us with any questions or concerns. Alcohol tolerance: >12% .
Fruity Witbier		70-75	Med-Low	17-24	A Witbier strain which produces lots of complex fruity esters while still prominently displaying classic Witbier character. Medium-low flocculation helps ensure classic Witbier haze. Alcohol tolerance: 12% .
Old World Saison Blend		85+	Med	18-25	A characterful blend of two classic Saison strains. Produces complex fruit and black pepper notes along with a reliable, fast and high degree of attenuation. We strongly encourage a free rise fermentation, starting at 22C and rising to ~27C for optimal results. NOTE: One of the strains in this blend contains the STA1 gene, meaning it might be a diastatic strain of Saccharomyces cerevisiae (pending data on whether it actually ferments dextrins or not). Many Saison yeasts are diastatic, due to the desire for very high attenuation levels. However extra care must be taken to ensure these yeasts do not cross-contaminate non-diastatic yeasts. Contact Escparment Labs with any questions or concerns. Alcohol tolerance: High .
St-Remy Abbey Ale		72-80	Med	18-24	This yeast strain isolated from a Belgian abbey is an excellent choice for Belgian-style beers, including abbey ales. This strain produces mixed fruity esters, while also highlighting malt aroma. This strain can be used at higher fermentation temperatures without becoming overly phenolic/spicy. Alcohol tolerance: >10% .
St. Lucifer Belgian Ale		75-85	Med	20-24.4	A high-character Belgian ale strain, able to produce high gravity beers with strong fruity and medium phenolic character. Excellent for strong golden ales and Tripels, but versatile for all Belgian ale applications. NOTE: This strain contains the STA1 gene, meaning it might be a diastatic strain of Saccharomyces cerevisiae (pending data on whether it actually ferments dextrins or not). Many industrial yeasts are diastatic, due to the desire for very high attenuation levels. However extra care must be taken to ensure these yeasts do not cross-contaminate non-diastatic yeasts. Contact us with any questions or concerns. Alcohol tolerance: >12% .
Wild Thing	Ontario	75-82	Med	25+	This wild Ontario ale yeast was isolated from an apple in a local orchard. Wild Thing produces distinct clove, spice, and subtle banana and apple fruit aroma. The taste is dry, spicy and clean. This yeast is most comparable to medium-attenuation Belgian-style ale yeasts. May require temperature ramping to 25C to ensure high attenuation. Alcohol tolerance: 9% .

Fermentis

Name	Lab	Source	Attenuation	Flocculation	Temp°F	Notes
SafAle™ T-58 Dry	Fermentis		70	Med	12-25°C (53.6-77°F) ideally 15-20°C (59-68°F)	A specialty ale yeast selected for its estery, somewhat peppery and spicy flavor. Yeast with a good sedimentation: forms no clumps but a powdery haze when re-suspended in the beer.
SafAle™ BE-256 Dry	Fermentis		82	High	12-25°C (53.6-77°F) ideally 15-20°C (59-68°F)	Active dry yeast recommended to brew a diversity of beers amongst which abbey style beers known for their high alcohol content. It ferments very fast and reveals subtle and well-balanced aromas. To maintain the aromatic profile at the end of the fermentation, we do recommend to crop the yeast as soon as possible after fermentation.
SafAle™ BE-134	Fermentis		90	Low	25-29°C (77-84°F)	This typical yeast strain is recommended for Belgian Saison-style beers and is characterized by a particularly high attenuation. It gives fruity aromas with a spicy character such as clove notes. This strain will produce highly refreshing and drinkable beers. Confirmed by the company to be a diastatic strain of Saccharomyces cerevisiae .
SafeAle™ WB-06	Fermentis		86	Low	18-24°C (64-75 °F)	This typical yeast strain is recommended for wheat beer fermentations and produces subtle estery and phenol flavor notes (POF+) such as clove notes typical of wheat beers. Confirmed by the company to be a diastatic strain of Saccharomyces cerevisiae

GigaYeast

Name	Source	Attenuation	Flocculation	Temp°F	Notes
GY003 Achouffe Belgian Ale		81-84 (medium gravity) 57-60 (7.7%+ abv)	Medium/Low	68-77	Abbey style yeast from the Belgian Ardennes. Produces aromatic, spicy clove-like notes and less fruity aromas than GY014. Moderately flocculant yeast that creates a slightly clearer beer than most Belgians.
GY007 Belgian Mix		79-81 (medium gravity) 67-70 (8.6%+ abv)	Low	68-77	A blend of Trappist Ale Yeast combine to create robust attenuation and a complex flavor profile. Spicy and fruity, this blend is slightly more flocculent than many Belgians. Good choice for High Gravity beers.
GY014 Scourmont Abbey Ale		79-81	Low	64-80	Classic Belgian yeast from one of the best known Trappist breweries. A fragrant yeast that produces delicious fruity aroma. Good choice for high gravity beers. Generally, the warmer this yeast is fermented the higher the level of fruit aromas produced.
GY015 Trappist Tripel		70-76	Low	66-74	Trappist Ale yeast from the mother of all Tripels. A balance of fruit and spice with a good malty finish provides a perfect complement for Belgian Ales, Dubbels and Tripels. Attenuation is on the slow side leaving more residual sweetness than our other Belgians. Less esters and phenolics than GY003 and GY014.
GY018 Saison 1	French Brewery	81-83 (medium gravity) 49-53 (6.2%+ abv)	Low	64-80	Traditional Saison yeast from a French craft brewery. Strong attenuator that produces a dry beer with a beautiful fragrance and the traditional Saison taste of fruit and pepper. Might be a diastatic strain of Saccharomyces cerevisiae if this strain is the same as WY3711 .
GY027 Saison Yeast 2	Traditional Saison	79-83 (medium gravity) 44-47 (5.5%+ abv)	Low	64-80	Creates the fruity/spicy aroma traditional to the style.  Warmer fermentation temps result in more intense flavor.  Produces a tartness not found in most of our yeast and a slightly sweeter beer than GY018
GY028 Belgian Wit		74-79	Very Low	64-80	Traditional Belgian Wit yeast from one of the classic producers of the style. Creates a delicious spicy nose and a somewhat tart beer. Attenuates dry and leaves a slightly cloudy beer - very low flocculation.
GY047 Saison Blend		80-83 (medium gravity) 49-53 (6.2%+ abv)	Low	64-80	A blend of Saison yeast. This Blend is a super robust attenuator that produces a complex flavor profile of fruit and spice.
GY048 Golden Pear Belgian Ale	Duvel Moortgat Brewery	78-85	Low	65-80	Traditional yeast from the originator of the Belgian Golden Strong Ale style. Robust attenuation makes this yeast an excellent choice for low or high gravity Belgian and farmhouse style ales. Leaves a dry, slightly tart finish with an estery profile reminiscent of apple and pear with a subdued level of spicy phenolics. This yeast produces a moderate amount of sulfide that will dissipate quickly with conditioning.
GY077 Quebec Abbey Ale	Canadian Brewery	75-83	Medium	68-80	From one of the first breweries in North America to create a successful line of traditional Abbey style ales. This Belgian ale yeast creates a malt forward beer with subtle fruity esters and a very small amount of clove notes. Robust attenuation makes this yeast an excellent choice for low or high gravity beers where a slightly sweet malty finish is desired. Perfect for the Belgian Dubbel and Tripel styles.

Imperial Organic Yeast

Name	Source	Attenuation	Flocculation	Temp°F	Notes
A20 Citrus	Unicorn Dust	74-78	Low	67-80	When you want to use Brett, but you don’t. Citrus cranks out orange and lemon aromas along with some tropical fruit. Use this strain at high temps for big ester production. As funky as saccharomyces gets. Same as WLP644 Sacch Trois .
B48 Triple Double	Westmalle	74-78	Medium	65-77	The perfect strain for your classic abbey ales. Triple Double produces moderate esters with low to no phenolic characteristics. This strain is tried and true and works perfectly in a production environment. Keep an eye on Triple Double, it likes to sit on top of the wort throughout fermentation which may result in a slow fermentation. Similar to Wyeast 3787 and WLP530 .
B64 Napoleon		77-83	Low	65-78	This yeast is an insane wort attenuator. Napoleon will destroy the sugars in your saison and farmhouse beers – even the ones in which most brewer’s strains have no interest. When all is said and done, Napoleon produces very dry, crisp beers with nice citrus aromas. Yeast settling times can be long, usually requiring filtration for bright beers. Similar to Wyeast 3711 . Determined to be a diastatic strain of Saccharomyces cerevisiae .
B45 Gnome	Achouffe	72-76	Medium-High	65-75	The Gnome is the yeast for brewing Belgian inspired beers in a hurry. This strain is extremely flocculent and drops out of the beer quickly after fermentation. Gnome produces a nice phenolic character that goes well with hops, as well as with caramel and toffee flavors. Great for Belgian ales that need to be crystal clear without filtration. Similar to Wyeast 3522 .
B51 Workhorse	Kasteel	72-77	Medium	65-75	Saison…no problem. Belgian stout, double… yep. Workhorse is the strain to use for a wide variety of brews. Super clean, this fast-attenuating strain has good flocculation characteristics. High alcohol tolerance makes this a great option for big Belgian beers. Similar to Wyeast 1581 .
B56 Rustic	Brasserie de Blaugies	72-76	Medium	68-80	This unique yeast can be used in your saison, farmhouse ale, or other Belgian styles where high ester levels are important. Rustic typically produces a lot of bubblegum and juicy aromas that compliment complex maltiness. Similar to Wyeast 3726 .
B63 Monastic	Chimay	74-78	Medium-Low	68-78	This strain is a beautiful yeast for fermenting abbey ales, especially quads; high alcohol and dark Belgian beers. Monastic will produce beers with a high level of phenolic character and esters. It can be slow to begin fermentation but will easily dry out high gravity worts. This strain is a low flocking strain, so expect it to stay suspended for a long time. Similar to Wyeast 1214 and WLP500 .
B53 Fish Finder	Orval	74-78	Medium	65-73	The classic choice for a Belgian IPA. Fish Finder has a very mild phenolic character balanced with moderate fruitiness. Often used for primary and then finished with a secondary Brettanomyces yeast. Similar to WLP510 .
B44 Whiteout	Celis White/Hoegaarden	72-76	Medium-Low	62-72	This is the strain for Belgian Wit style beers. Whiteout produces an excellent balance of spicy phenolic character and esters. Along with the necessary aromatics, this strain produces a significant amount of acidity which is perfect for wits and other light colored Belgian ales. Whiteout can be flocculent during fermentation, then become non-flocculent at the end. This may lead to slower than normal fermentation. Similar to Wyeast 3944 and WLP400 .

Inland Island Yeast Laboratories

Name	Source	Attenuation	Flocculation	Temp°F	Notes
INIS-201 Belgian Monk Ale I	Monastery brewery in Southern Belgium	72-76	Medium	68-78	High alcohol tolerance and plum like notes create great dark Belgian beers.
INIS-202 Belgian Monk Ale II		73-77	Medium	65-75	High alcohol tolerance. Beer ferments clean with a full body and full malt flavor. Notes of dried fruit.
INIS-203 Belgian Monk Ale III	Monastery brewery	74-78	Medium	64-78	High alcohol tolerance. Isolated from a world class monastery brewery known for brewing high gravity ales with complex esters and phenols.
INIS-204 Belgian Monk Ale IV		73-77	Medium	65-75	High alcohol tolerance. Used to brew a beer with a dry and acidic finish but otherwise clean.
INIS-222 Belgian Gnome Ale		72-76	High	65-76	High alcohol tolerance. Distinctive, estery and phenolic profile.
INIS-225 Belgian American	Famous Belgian style brewery near Montreal	75-79	Medium	65-80	This yeast produces a beer that is dry with a low ester profile. Phenolics increase as this yeast is fermented at higher temperatures.
INIS-231 Belgian Gold		74-78	Low	64-80	Very high alcohol tolerance. Yeast used to brew a classic strong ale in the Belgian tradition. High alcohol tolerance with mild phenols and fruity esters.
INIS-241 Belgian Wit I		72-76	Medium	64-74	High alcohol tolerance. Used to brew wit style beer. Notes of pear, apple, stone fruit, and a slight acidity/tartness in the finish. Very top heavy.
INIS-242 Belgian Wit Devil		72-76	Medium	62-75	High alcohol tolerance. Similar to Belgian Wit I but with more phenols and clove. Very top heavy requiring a lot of extra space in the fermenter to prevent pushing all of the yeast out of the blow off tube.
INIS-251 French Ale		68-75	Med-High	63-73	This strain produces a clean beer that complements malt with lower ester production than traditional Belgian strains. Excellent yeast choice for a Biere de Garde and specialty beer. Might be a diastatic strain of Saccharomyces cerevisiae .
INIS-291 Farmhouse: Saison		74-79	Medium	70-95	High alcohol tolerance. A dynamic yeast that produces a wide range of phenols and esters. Notes of strawberry, hay, and spice. Leaves the finish slightly tart and with an excellent mouth feel.
INIS-292 Saison: Belgian I		76-80	Low	70-95	High alcohol tolerance. Traditional saison strain isolated from a premier Belgian Brewery. Fruity, spicy, slightly tart, and leaves the beer dry. Known for stalling towards the end of the fermentation around 5-7 plato, but with additional heat and time will finish.
INIS-293 Saison: Belgian II		78-85	Medium	68-78	Medium alcohol tolerance. Strain is more fruity than Belgian I but from a similar source. Rumored to be a part of a mixed fermentation. This isolated strain is more reliable than Saison: Belgian I but with less depth.
INIS-294 Saison: French		77-83	Low	77-83	High alcohol tolerance. A saison yeast that produces more phenols than the Belgian Saison strains. Notes of pepper and citrus along with other spices. Leaves behind a pleasant mouthfeel in the beer despite being highly attenuative. It is less likely to stall than the Belgian Saisons.
INIS-295 Saison: Phantom		74-79	Low	70-84	This strain produces a saison with subtle spiciness and moderate ester production. The beer finishes dry and tart with no sluggishness like other Belgian Saison yeast.
INIS-296 Saison: Walloon		80-88	Medium	72-80+	This strain produces mild acidity, subtle spicy phenols and some light “funk”. Wide range of phenol and ester production based on fermentation temperature.
INIS-298 Saison: Baron	France	70-80	Medium	70-80	A true Bier-de-Garde yeast from France. Yeast produces a briny flavor and notes of white pepper and straw.
INIS-317 English Ale VII		65-69	Medium	80+	This strain produces a malty beer that is slightly fruity for lower gravity beers. Very high alcohol tolerance makes this a good yeast choice for beers above 10% ABV. INIS-317 English Ale VII has been identified using polymerase chain reaction (PCR) to contain the glucoamylase gene (STA1), which can be an indicator of a diastatic strain of Saccharomyces cerevisiae. As such, INIS-317 has the ability to utilize some dextrins which are unfermentable to most species of S. cerevisiae, and thus achieve a very high level of attenuation. However, INIS-317 is not considered a contaminant and will not over attenuate finished beer when a high level of attenuation is expected .
INIS-491 Saison: French		77-83	Low	65-77	A saison strain that produces more phenols than the Belgian Saison strains. Notes of pepper and citrus along with other spices. This yeast leaves behind a pleasant mouthfeel in the beer despite being highly attenuative. It is less likely to stall than the Belgian Saison strains. This strain has been identified using polymerase chain reaction (PCR) to contain the glucoamylase gene (STA1), which can be an indicator of a diastatic strain of Saccharomyces cerevisiae. As such, INIS-491 has the ability to utilize some dextrins which are unfermentable to most species of S. cerevisiae, and thus achieve a very high level of attenuation. However, INIS-491 is not considered a contaminant and will not over attenuate finished beer when a high level of attenuation is expected .

Jasper Yeast

Name	Source	Attenuation	Flocculation	Temp°F	Notes
JY008 - Saint Nicholas, Belgian Ale I	Poperinge, Belgium	70-78	Med-High	68-78	he yeast is very fruity and does well on a wide range of temperatures. At the lower temperatures maltiness comes more forward, and at the higher range yeast esters are more pronounced.
JY011 - Belgian Ale II	Antwerp, Belgium	73-78	Med-High	62-74	Rumored to originate from a famous brewery in Antwerp. Comparatively clean and versatile. Produces less aromatics than other Belgian yeasts, and is therefore more suited for malt-driven beers and Belgian-style pale ales, but still carries the Belgian aromatic flair.
JY027 - Belgian Ale V, Scourmont	Belgium	76-81	Med-High	62-74	Trappist yeast from one of the six Trappist breweries from Belgium. Strong fruity esters at elevated fermentation temperatures, but more subdued and spicy at lower fermentation temperatures.
JY031 - Nova Ale Yeast	Ashburn, Virginia	71-80	Very low	68-85	A true local strain! Isolated in Ashburn, Virginia in 2008. The first native Virginia yeast used in commercial beer since prohibition (Farmwell Wheat and Native Son, both Lost Rhino Brewing Company). Higher fermentation temperatures are preferred with this strain. Producer of high levels of fruitiness above 26 ºC (80 ºF), earthy notes are present at lower fermentation temperatures (20 ºC, 68 ºF). Since it is a wild Saccharomyces cerevisiae strain one can expect drift when repitched for many generations.
JY056 - Poperinge Saison	Famous Brasserie in Southern Belgian/Northern France region.	79-85	Very low	65-77	Aggressive, attenuative and outspokenly estery and peppery. Great for Saison and Farmhouse style beers at higher temperatures, in the lower range good for more traditional Belgian styles. Good to finish off a beer that has problems fermenting with another yeast.
JY064 - Belgian Ale VII	Belgium	70-80	Low	59-75	Belgian Abbey yeast producing intense esters at higher temperatures, and strong spice notes at lower temperatures.
JY087 - Sacc Brux	Belgium	70-80	Very Low	70-80	Similar to Sacch Trois; forms a pellicle. Determined to be a diastatic strain of Saccharomyces cerevisiae .
JY104 - Benedict Abbey	Small brewery in Flemish Brabant, Belgium.	75-80	Low	68-77	JY104 was handed to Jasper Akerboom when he toured some small microbreweries in the Netherlands and Belgium by a friendly microbrewer. This strain originally belonged to a small brewery in Flemish Brabant in Belgium. The brewery was acquired by a large macrobrewery, and management decided to do away with this precious yeast. Fortunately passionate homebrewers and beer enthusiasts were able to keep some of the yeast going and you can use it now as well! This strain ferments fast, and aggressive. It can be under pitched easily, and attenuates deep. Great esters and phenols, can be slightly peppery. Flocculates slow, but can withstand spunding without a problem. This yeast is great for lighter colored Belgians, but is great for darker Belgians as well. This strain has not been fully characterized, so we do not know what gravity this yeast will ferment. We do know that it attenuates very well, and the initial tests have indicated that can ferment easily to 10% ABV.
JY110 - NOVA Ale Yeast 2	Northern Virginia	75-80	Low	75-100	This yeast differs from JY031 Nova Ale Yeast 1 by being slight more toned down in the aromatics and flavor department. Isolated in Northern Virginia, this strain is truly local. Power to VA! Since this is a new variety of Saccharomyces cerevisiae, this strain has not been fully characterized yet. Feel free to share your information with us if you use this strain! This strain will be perceived slightly Belgianesque, but at lower fermentation temperatures will be lower in aromatics. Can slow down when temperature is low. Likes it warm.
JY146 - Protocetid Ale	Calvert Marine Museum in Solomons, MD.	>80	Very low	max 90	This yeast is the famous strain isolated from the Calvert Marine Museum in Solomons, MD. This strain was isolated from Protocetid bone, discovered by Jason Osborne, the president and co-founder of Paleo Quest, a non-profit citizen-science organization for the advancement of the sciences of paleontology and geology through material contributions to museum collections, field exploration, scientific publication and education. This yeast is used for the famous Lost Rhino Brewing Company Bonedusters Ale. This yeast is hard to work with, it has the tendency to stop fermenting for a week after 30% attenuation, after which it picks back up and finishes out. Not for the faint of heart! Expect a Belgian character, with some tartness. Keep the desired ABV low during your recipe development, this strain is not suited for high-gravity worts. Finishes crisp and fruity, with a pleasant fizz.
JY164 - Belgian Ale XIV	East Flanders, Belgium	75-80	Low	65-80	Well suited for Golden Strong and other Belgian styles that do well with a spicy yeast strain. Can resist high ethanol concentrations.
JY206 - Belgian Ale XV	Ardennes, Belgium	73-77	High	65-77	Suitable for a wide variety of Belgian styles, depending on fermentation characteristics and grain bill. Tends to be spicy and fruity, with spiciness being on the forefront at lower fermentation temperatures, and estery at the higher range.
JY207 - Belgian Wit I	Hoegaarden	70-77	Low	63-76	Spicy and phenolic, with a nice estery finish. Great for witbier, Grand Cru-style wit and specialty beers. Belgian Styles, mainly Belgian Wit and Grand-Cru, but does well in Blonde, Belgian Tripel and Specialty.
JY240 - Belgian Ale VIII, Sixtus	Belgium	78-86	Low	70-80	Arguably the most used Trappist yeast outside of the original brewery. Well suited for the dryer Belgian styles such as Belgian Pale, Blonde, Tripel and Golden Strong.

Lallemand Brewing

Name	Source	Attenuation	Flocculation	Temp°F	Notes
SOURVISIAE®	Genetically engineered	Med-High	Med-High	59-72	Genetically engineered strain of S. cerevisiae that produces very high levels of lactic acid with a slightly fruity flavor and aroma and is free from off-flavors that can be produced by lactic acid bacteria such as THP. This yeast produces a very acidic beer, with final beer pHs in the range of 3.0 and lactic acid in the range of 8 – 15g/L. Vigorous fermentation can be completed within 5 days. It is not recommended to re-pitch by the manufacturer, although some brewers report success propagating it into a larger biomass with a starter . See also this MTF thread and this MBAA Podcast. Evan Coppage reported getting 65-70% viability on subsequent re-pitches, with a slower start but comparable results to initial pitch (see this MTF thread). See "Diving Deep In To Sourvisiae" by Dr. Bryan Heit for fermentation and acidification dynamics, pitch rates, repitchability and other factors potentially of interest in the brewery.
Lallemand Belle Saison - DRY	Lallemand	High		59-95	Belle Saison is also a prodigious sulfur producer, so extended conditioning may be necessary. Verified to be a diastatic strain of Saccharomyces cerevisiae, and killer neutral . Belle Saison yeast is killer neutral, which means that killer wine strains will not kill it . See this MTF thread for more information on this strain. This might be the same strain as WY3711 . Formerly branded as "Danstar".
Lallemand Abbaye Belgian Ale Yeast - DRY	Lallemand	Med-High	Low	63-80	Abbaye is an ale yeast of Belgian origin selected for its ability to produce great Belgian style beers including high gravity beers such as Dubbel, Trippel and Quads. The propagation and drying processes have been specifically designed to deliver high quality beer yeast that can be used simply and reliably to help produce ales of the finest quality. Formerly branded as "Danstar". This strain has been reported to be a genetic hybrid between Saccharomyces cerevisiae and Saccharomyces kudriavzevii .

Mainiacal Yeast (CLOSED)

Name	Source	Attenuation	Flocculation	Temp°F	Notes
BB 3	Spontaneous capture	70-82		68-78	This is an interesting strain as it has hints of stone fruit as well as a Saison like quality to it lending citrus notes. Commercial pitches only .
MYJuicy	Maine Maple Tree	70-85		65-80	Wild Sacc strain caught and isolated from a maple tree in Maine. Produces lots of tropical fruit esters. Commercial pitches only .
Infectious Behavior		80-100		65-80	Currently this species is a hot topic amongst infections in breweries. As it has the ability to metabolize starches and complex sugars, which most primary yeast fermentation leaves behind. We isolated this out of an infected beer and found it to have very Saison like qualites. Commercial pitches only .
Sacc Full of Fruit	Wild Capture	70-80		65-78	Stone fruit galore! This Sacc strain creates massive stone fruit notes such as peach, plum and cherry. It works very well for West Coast IPAs, NEIPAs, and a bunch of other styles! We especially like this when in a beer double dry hopped with Belma and Mosaic. Commercial pitches only .
Citrus King	Wild Capture	70-82		62-80	This particular Sacc c strain produces huge notes of citrus peels and a hint of tropical fruit. It pairs extremely well with the citrus forward new age hops as well as many of the older varieties. We find its perfect for citrusy NE IPAs. This strain also tends to keep the beer hazier given enough protein is also in the wort. Commercial pitches only .

Mangrove Jack's Dry Yeasts

Name	Source	Attenuation	Flocculation	Temp°F	Notes
M21 Belgian Wit		High	Low	64-77	A traditional top-fermenting yeast that has a good balance between fruity esters and warming spice phenolics. The yeast will leave some sweetness and will drop bright if left long enough. Suitable for Witbier, Grand Cru, Spiced Ales and other specialty beers.
M29 French Saison Ale (previously M27)		Very High	Med	79-90	Characterful beers with spicy, fruity and peppery notes ideal for Belgian Saison or farmhouse style beer. Suited for brewing all Belgian ales, including Quadruples of up to 14% abv. M29 description: French Saison yeast is an exceptional, highly attenuative top-fermenting ale yeast, creating distinctive beers with spicy, fruity and peppery notes. Ideal for fermentation of farmhouse style beer . Confirmed to be a diastatic strain of Saccharomyces cerevisiae .
M31 Belgian Tripel		Very High	Med	64-82	Provides a fantastic complex marriage of spice, fruity esters, phenolics and alcohol. It is also very attenuative with a high alcohol tolerance making it perfect for a range of Belgian styles. Suitable for Belgian Tripel and Trappist style beers.
M41 Belgian Ale		Very High	Med	64-82	Spicy and phenolic, this yeast emulates the intensity and complexity of some of the best monastic breweries in Belgium. High attenuation and alcohol tolerance allow you to brew a huge range of Belgian beers. Suitable for Belgian Strong Golden and Belgian Strong Dark Ales.
M47 Belgian Abbey Yeast		High	High	64-77	Moderately alcohol tolerant with fewer phenols than Belgian Ale, this yeast is exceptionally fruity with hugely complex esters and is highly flocculant.

Mogwai Labs (Australia)

Name	Source	Attenuation	Flocculation	Temp°C	Notes
MOG-301 Reverence I	Trappist brewery in north Belgium	70-76	Low	19-24	Not diastatic.
MOG-301 Ardennes		70-76	High	19-24	Not diastatic.

Omega Yeast Labs

Name	Source	Attenuation	Flocculation	Temp°F	Notes
Abbey Ale C - (OYL-018)		74-78	Medium-Low	68-78	From a famous Trappist brewery, this yeast produces the distinctive fruitiness and plum characteristics. Excellent yeast for high gravity beers, Belgian ales, Dubbels and Tripels. Compares to WLP500 and WY1214. Commercial pitches only.
Belgian Ale A (OYL-024)		72-85	High	65-78	Versatile strain for the production of classic Belgian style ales. This strain produces a beautiful balance of delicate fruit esters and subtle spicy notes, with neither one dominating. Unlike many other Belgian style strains, this strain is highly flocculent and results in bright beers. Compares to Compares to WLP550 and WY3522. Available to homebrewers.
Belgian Ale D (OYL-019)		74-78	Low	64-80	The best choice for brewing golden strong ales. This alcohol tolerant strain will produce a complex ester profile balanced nicely with subtle phenolics. Malt flavors and aromas will remain even with a well attenuated dry, tart finish. It may continue to produce CO2 for an extended period after packaging or collection. Compares to WLP570 and WY1388. Commercial pitches only.
Belgian Ale DK (OYL-049)		73-80	Medium	67-70	Clean Belgian type ale yeast. Good for Belgian style pale ales and amber ales. Biscuity, ale-like aroma with accentuated hop flavor and bitterness. Slight sulfur will be produced during fermentation, which can give the yeast a lager-like flavor profile. Compares to WLP515. Commercial pitches only.
Belgian Ale O (OYL-046)		74-80	Medium	66-72	A Trappist style ale yeast. Produces dry beer with slight acidic finish, but cleaner than OYL-018 and OYL-028. Good choice for high gravity beers, Belgian ales, Dubbels and Tripels. Compares to WLP510. Commercial pitches only.
Belgian Ale R (OYL-020)		73-82	Medium	65-75	Great choice for use in Belgian dark strong ales. This strain has a relatively “clean profile” which allows a rich malt and distinctive ethanol character to shine. Delicate dried fruit esters can be produced when used at higher fermentation temperatures or in a high gravity wort. Compares to WLP540 and WY1762. Commercial pitches only.
Belgian Ale W (OYL-028)		74-78	Medium	64-78	Classic strain for brewing Belgian Dubbel or Belgian Tripel. This strain produces a nice balance of complex fruity esters and phenolics, making it desirable for use in other Belgian style ales as well. A flocculent, true top cropping yeast (additional headspace is recommended), that will work over a broad temperature range. Makes a great Belgian style “house” strain. Compares to WLP530 and WY3787. Available to homebrewers.
Belgian Dark Ale A (OYL-040)		74-79	Medium	65-80	Belgian ale yeast that is a high acid producer with balanced ester and phenol production. High alcohol tolerance. Spicy, tart, and dry on the palate with a very complex finish. Compare to WY3822. Commercial pitches only.
Belgian Saison I (OYL-027)		76-80	Low	70-95	Most widely used farmhouse ale yeast. A traditional yeast that is spicy with complex aromatics, including bubble gum. It is very tart and dry on the palate with a mild fruitiness. Will yield a crisp, mildly acidic finish that will benefit from elevated fermentation temperatures. This strain is notorious for a rapid and vigorous start to fermentation, only to stick around 1.035 S.G. Fermentation will finish, given time and warm temperatures. Warm fermentation temperatures, at least 90°F (32°C), or the use of a secondary strain can accelerate attenuation. Compares to WLP565 and WY3724. Commercial pitches only.
Belgian Saison II (OYL-042)		74-79	Medium	70-84	This strain produces complex esters balanced with earthy/spicy notes. Slightly tart and dry with a peppery finish. A perfect strain for Farmhouse ales and Saisons. Compares to WY3726. Commercial pitches only.
Belgian Wheat (OYL-029)		72-76	Medium	64-74	Produces beers with moderate esters and minimal phenolics. Apple, bubblegum, and plum-like aromas blend nicely with malt and hops. This strain will finish dry with a hint of tartness. Compares to WY3942. Commercial pitches only.
Biere de Garde (OYL-039)		74-79	Low	70-84	Ferments well with low to moderate ester production and subtle spiciness. Malty and full on the palate with initial sweetness. Finishes dry and slightly tart. Compares to WY3725. Commercial pitches only.
French Saison (OYL-026)		77-83	Low	65-77	Versatile strain that produces Saison or farmhouse style beers as well as other Belgian style beers that are highly aromatic (estery), peppery, spicy and citrusy. This strain enhances the use of spices and aroma hops, and is extremely attenuative but leaves an unexpected silky and rich mouthfeel. This strain can also be used to re-start stuck fermentations or in high gravity beers. Compares to WY3711. Determined to be a diastatic strain of Saccharomyces cerevisiae . Commercial pitches only.
Grand Cru (OYL-023)		72-76	Low	63-76	Widely used strain in the production of Witbier, Grand Cru, sweet mead and cider. Produces spicy phenolics which are balanced nicely by a complex ester profile. The subtle fruit character and dry tart finish will complement wheat malt, orange peel and spice additions typical of Wits. Compares to WLP720 and WY3463. Commercial pitches only.
Saisonstein's Monster (OYL-500)		80-90	Low	65-78	The first in our line of hybrid strains. This strain is a genetic hybrid resulting from the mating of strains OYL-026 and OYL-027, created by and available exclusively from Omega Yeast. Less phenolic and more fruit character than 026. Exhibits some of the bubble gum character of 027. Omega Yeast Labs Exclusive. This might be a hybrid of S. boulardii and a diastatic strain of S. cerevisiae . Available to homebrewers.
Wit (OYL-030)		72-76	Medium	62-75	Produces a complex flavor profile dominated by spicy phenolics with low to moderate ester production. It is a great strain choice when you want a delicate clove profile not to be overshadowed by esters. It will ferment fairly dry with a slightly tart finish that compliments the use of oats, malted and unmalted wheat. This strain is a true top cropping yeast requiring full fermenter headspace of 33%. Compares to WLP400 and WY3944 vs Omega Yeast Labs Exclusive. Commercial pitches only.

Propagate Lab

Name	Source	Attenuation	Flocculation	Temp°F	Notes
BTN-46 Canadian Saison	A small craft brewery in Quebec				Fall 2020 release; may not be available year round .
BTN-67 Anse	Bottle of organic, sparkling Gamay wine from Anse, France				produces a fairly neutral profile with subtle white pepper, clove, and figs. It finishes very dry but has a fuller mouthfeel due to glycerol production .
MIP-211 Belgian Ale I		Mid - High 70's	Med	68-78	Produces subtle banana esters .
MIP-212 Belgian Ale II		Mid - High 70's	Med	68-78	Slightly phenolic and works best in higher alcohol beer .
MIP-213 Belgian Ale III		Mid - High 70's	Med	68-78	Produces stone fruit esters such as plumb; recommended for dubbels and quads .
MIP-220 Belgian Dwarf Ale		Mid - High 70's	High	68-78	Produces a wide range of esters and phenols depending on fermentation temperature. It's a versatile yeast and ferments fast .
MIP-231 Belgian Wit Ale I		Mid 70's	Med	65-74	Produces pear and red apple esters .
MIP-232 Belgian Wit Ale II		Mid 70's	Med	63-74	Produces clove/white pepper phenols .
MIP-300 Farmhouse		High 80's	Med	70-85	Notes of hay and strawberries. Likely to be a diastatic strain of Saccharomyces cerevisiae .
MIP-302 French Saison		High 80's	Med	70-85	Notes of spice and fruit. Determined to be a diastatic strain of Saccharomyces cerevisiae .
MIP-303 Saison I	Isolated from a well known Belgian saison brewery	High 80's to mid 90's	Low	70-85	Might require elevated fermentation temps to prevent it from stalling out at 5 plato. Likely to be a diastatic strain of Saccharomyces cerevisiae .
MIP-304 Saison II	Isolated from a well known Belgian saison brewery (editor's note: likely to be Dupont)	Mid 80's	Low	70-80	less estery and phenolic than MIP-303 and is less likely to stall out near the end of fermentation. Likely to be a diastatic strain of Saccharomyces cerevisiae .
MIP-310 Daffodil Saison	Somewhere in France	Low 70's	Med	63-74	Produces a minerality, tastes dry .
MIP-330 French Ale Yeast		Low 70's	High	63-74	Good for malty saison styles and 12%+ ABV .

RBY Laboratories

Name	Source	Attenuation	Flocculation	Temp°F	Notes
RBY41 French Saison		77-83	Low	65-75	Determined to be a diastatic strain of Saccharomyces cerevisiae . Might be the same strain as WY3711.
RBY58 - Fantome Saison Clone #1	Fantome	70-80	Low	75-85

RVA Yeast Labs

Name	Source	Attenuation	Flocculation	Temp°F	Notes
RVA 261 Saison I	Dupont	65-75	Med	75+	fruity, bubblegum esters with all the spice and pepper that makes Saison so appealing
RVA 262 Saison II		75-82	Med	67-77	French origin, this strain produces a bit less of the fruity, bubblegum esters with less spice and pepper then RVA 241. Determined to be a diastatic strain of Saccharomyces cerevisiae . Might be the same strain as WY3711
RVA 263 Ghost Ale	Fantome	74-84	Med	65-80	Ripened fruit esters and a crisp earthy finish can be achieved even at lower temperatures with this Belgian farmhouse strain
RVA 806 Lickinghole Creek Ale	Virginia’s LHCB farm	78-85	Med	68-74	Citrus esters, a nose of sweet honey and a dash of phenolic spice, this strain will complement a variety of dry Belgian style beers. We highly recommend this strain for Belgian triple and Saison.

Saccharolicious

Name	Source	Attenuation	Flocculation	Temp°F	Notes
Demonical					Popular yeast strain from a well-known Belgian brewery. Because of its ester-dominated fermentation profile, this yeast strain is often used in strong Belgian ales. Other beer styles where this yeast strain can be used are Belgian-style IPA, Belgian blond and Tripel.
Trappist O					Relatively clean Belgian yeast from a Trappist brewery in the Ardennes. A good choice for most Belgian ales, but especially strong pale Belgian ales. In combination with Brett I, this strains can be used for brewing Belgian specialty ales.
Wheat I					Belgian Wit yeast from a brewery in West Flanders.
Castle					Alcohol tolerant yeast strain suitable for strong and sweet ales. This yeast strain originates from a West Flemish brewery.
Gnome					Yeast strain from a brewery in the Belgian Ardennes. Very versatile strain that fits most Belgian ale styles because of its balanced fermentation profile.
Pixie					Slightly phenolic and spicy yeast strain from West Flanders. This is a versatile yeast strain that fits both malty and hoppy beers.

Sleight Beer Lab

Name	Source	Attenuation	Flocculation	Temp°F	Notes

SouthYeast Labs

Name	Source	Attenuation	Flocculation	Temp°F	Notes
P1 Musserweissen	Dwarf Peach (Clemson, SC)	78.7%	Low		Use for Wit, Heffe, Saison, Kölsch. "Medium" acidity. Banana, peach esters; citrus peel and clove phenolics. 4-6 weeks in primary. Hazy, notes of champagne .
N3 Native Cider	Nectarine (South Carolina)	83.2%	High		Use for light Belgian ales, cider, wine. "No acidity". Apple cider esters; light pepper spice phenolics. 3-4 weeks in primary .
B3 Farmhouse Ale	Blueberry (Clemson, SC)	79.3%	Low		Use for saison, farmhouse ales. "Medium acidity". Tart esters; straw spice phenolics. 4-6 weeks in primary. It produces notes of straw and spice - enough to pique the palate but not enough to offend. It even produces enough acid to leave a noticeable tartness in the beer. It will leave the beer hazy with yeast at the end of its 4-6 week fermentation .
HS2 New Abbey Ale	Honeysuckle (Walland, TN)	78%	Medium		Use for Belgian and Abbey type ales. "Low acidity". Red wine esters; cracked pepper corn phenolics. 3-4 weeks in primary. Full flavor and complex. .
N1 Native Strong Ale	Nectarines (Clemson, SC)		High		N1 was one of the first wild yeasts we ever captured and a good portion of why we fell in love with wild yeast. N1 is our workhorse yeast, finishing semi-dry and clean with a hint of champagne. It flocculates well after 3-4 weeks. Good for pale ales, strong ales, mead and cider.

The Yeast Bay

All single and mixed blends will contain ~80 billion cells per homebrew sized vial .

Name	Source	Attenuation	Flocculation	Temp°F	Notes
Saison Blend		80	Med	70-78	Blend of 2 yeast strains, Flavors of pepper, grapefruit, Orange zest
Wallonian Farmhouse		81-88	Med	68-78	Slight earthy funk and tart character to the beer; we recommend controlling the dryness by adjusting the mash temperature or adding malts or adjuncts to the mash tun that will lend some body and residual sweetness to the beer. Although it can be fermented at lower temps, for full flavor it is recommended to start fermentation in the 70°F's, and let it free-rise to the low to mid 80°F's . Determined to be a diastatic strain of Saccharomyces cerevisiae .
Wallonian Farmhouse II		80-82	Med-Low	68-80	This is a single strain of Saccharomyces cerevisiae isolated from the same source as our Wallonian Farmhouse strain, a well-known brewery hailing from the Walloon region of Belgium. Slightly less attenuative and exhibiting a more restrained phenolic and expressive ester profile than our original Wallonian Farmhouse, this yeast is a great choice for any classic saison style beer in which a balance of fruitiness and rustic farmhouse character is desired. Wallonian Farmhouse II works very well in conjunction with Brettanomyces owing to its robust and complex ester and phenol profile, so well that it has the honor of being the dominant saison strain in our new Saison/Brettanomyces Blend II culture .
Wallonian Farmhouse III		80-82	Med-Low	68-80	This is a single strain of Saccharomyces cerevisiae isolated from a well-known brewery hailing from the Walloon region of Belgium. This strain is as attenuative as our original Wallonian Farmhouse and exhibits a more balanced profile of ester and phenols. This yeast is similar to a classic saison strain offered by many other yeast manufacturers, without the slow/low attenuation and stalling issues often observed in those cultures. Wallonian Farmhouse III works very well in conjunction with Brettanomyces owing to its balanced and complex ester and phenol profile .
Saison Blend II		80-86	Med	68-80	This saison blend is the Saccharomyces portion of our Farmhouse Sour Ale, available to you as a result of popular demand from the commercial brewing crowd. This combination of Saccharomyces strains embodies the balanced fusion of the two foremost saison flavor/aroma characters, fruitiness and earthiness. Each Saccharomyces strain in this blend produces flavor compounds that serve as the yin to the other's yang, and the result is an exceptionally complex yet balanced flavor and aroma profile. One strain will serve to create an ester profile of grapefruit and orange zest, while the other will produce a mild earthiness and spiciness. Close your eyes while drinking a beer fermented with this blend, and you'll feel like you're laying on freshly turned earth in an old citrus grove. Contains a strain that is determined to be a diastatic strain of Saccharomyces cerevisiae .
Dry Belgian Ale		85-100	Med-High	68-74	Dry Belgian Ale is single strain of Saccharomyces cerevisiae isolated from a unique golden strong ale. The profile is a complex and balanced mix of apple, pear and light citrus fruit with some mild spicy and peppery notes. The apparent attenuation of this strain ranges anywhere from 85-100%, depending upon the mash profile and the grist composition. For a yeast that's as dry as it is, it creates beers with a surprising amount of balance even without the use of specialty grains or adjuncts. While we haven't completed our own tests in house, this yeast is used at the brewery from which it was isolated to make big beers that are in the neighborhood of 12-16% ABV and sufficiently dry. Use Dry Belgian Ale as a primary fermenter in any big Belgian beer, or to unstick that pesky stuck fermentation. Determined to be a diastatic strain of Saccharomyces cerevisiae .
Northeastern Abbey		77-81	Med-Low	68-73	This yeast was isolated from a beer crafted by a well-known producer of Belgian-style ales in the Northeastern United States. This yeast produces a very mild spiciness and earthy flavor and aroma which is complemented by a subtle but magnificent array of fruity esters, including pear and light citrus fruit. The brewery from which this strain was isolated uses it in a very versatile manner across an array of Belgian styles. We prefer using this yeast for any and all light Belgian beers, including Wit, Belgian Pale and Belgian Blond, in addition to any experimental fruit beers in which a more unique and robust flavor and aroma profile is desired. Expect this yeast to produce a large, thick krausen.
Funktown Pale Ale		78-80	Medium-Low	68-74	Funktown Pale Ale is a blend of our Vermont Ale strain and a unique strain of Brettanomyces that is well suited for primary fermentation Saccharomyces "Bruxellensis" Trois. The combination of the citrus/peach esters from the Vermont Ale strain and the very light funk and pineapple/mango esters from the Brettanomyces produces a unique flavor and aroma profile that is fruit-forward. Expect this blend to finish drier than the Vermont Ale. We recommend following a similar fermentation scheme as is used for the Vermont Ale, fermenting at 67-69 ºF for 3-4 days, and then raising the temperature to 72 ºF until a stable gravity is reached. Contains a strain that is determined to be a diastatic strain of Saccharomyces cerevisiae .
Flanders Specialty Ale		80-90	Medium	68-80	This is a single strain of Saccharomyces cerevisiae isolated from a fascinating Belgian producer of a wide array of traditional Belgian beer styles. This is a versatile yeast that will ferment fairly dry and produce a balanced flavor and aroma profile laced with a myriad of esters and phenols. While fermenting to dryness similar to our Dry Belgian Ale, there remains a pleasant fullness in the mouthfeel and a malt backbone that shines. If you would like the final gravity to remain a bit higher, we recommend mashing around 156 F .
Pakruojis Lithuanian Farmhouse	Not advertised	90-100	Low	75-96	Pakruojis Lithuanian Farmhouse is a single strain of STA1+ Saccharomyces cerevisiae, isolated from a Lithuanian brewery. This yeast produces beer with a dry, crisp and silky mouthfeel, an ester profile of citrus, and a balanced earthiness with undertones of white peppercorn. This strain exhibits high diastatic activity .

WHC Lab

Name	Source	Attenuation	Flocculation	Temp°F	Notes
Farmhouse Vibes - Diastatic Saison Yeast - Dehydrated		80+	Low to Medium	19°C to 26°C	French saison yeast. Determined to be a diastatic strain of Saccharomyces cerevisiae.

White Labs

• 1.5 to 3.0 billion per milliliter; homebrew PurePitch® packages contain 60-120 billion cells. See White Labs FAQ for an explanation on varying cell counts in PurePitch® packages, and the public Yeastman database.
• See White Labs list of Belgian yeast strains and characteristics, including phenols/spiciness.
• See The WL Vault, which contains many non-conventional yeasts and bacteria.

Name	Source	Attenuation	Flocculation	Temp°F	Notes
WLP072 - French Ale		69-75	Med-High	63-73	Clean strain that complements malt flavor. Low to moderate esters, when fermentation temperature is below 70°F. Moderate plus ester character over 70°F. Low diacetyl production. Good yeast strain for Biere de Garde, blond, amber, brown ales, and specialty beers. Seasonal Availability: May - Jun.
WLP400 - Belgian Wit Ale	Hoegaarden/Celis	74-78	Low-Med	67-74	Slightly phenolic and tart, this is the original yeast used to produce Wit in Belgium.
WLP410 - Belgian Wit II Ale	Moortgat Brouwerij (via Ommegang?)	70-75	Low-Med	67-74	Less Belgian-like phenolics than WLP400 and more spicy. Will leave a bit more sweetness, and flocculation is higher than WLP400. Use to produce Belgian Wit, spiced Ales, wheat Ales, and specialty Beers.
WLP500 - Monastery Ale	Chimay	75-80	Low-Med	65-72	From a Belgian monastery where monks traditionally made beer, this yeast produces the distinctive fruitiness and plum characteristics. Excellent yeast for high gravity beers, Belgian ales, Dubbels and Tripels.
WLP510 - Bastogne Belgian Ale	Orval	74-80	Med	66-72	A high gravity, Trappist style ale yeast. Produces dry beer with slight acidic finish. More ‘clean’ fermentation character than WLP500 or WLP530. Not as spicy as WLP530 or WLP550. Excellent yeast for high gravity beers, Belgian ales, Dubbels and Tripels.
WLP515 - Antwerp Ale	De Koninck	73-80	Med	67-70	Clean, almost lager like Belgian type ale yeast. Good for Belgian type pales ales and amber ales, or with blends to combine with other Belgian type yeast strains. Biscuity, ale like aroma present. Hop flavors and bitterness are accentuated. Slight sulfur will be produced during fermentation, which can give the yeast a lager like flavor profile. Seasonal Availability: Nov - Dec.
WLP530 - Abbey Ale	Westmalle	75-80	Med-High	66-72	Used to produce Trappist style beers. Similar to WLP500, but is less fruity and more alcohol tolerant (up to 15% ABV). Excellent yeast for high gravity beers, Belgian ales, Dubbels and Tripels.
WLP540 - Abbey IV Ale	Rochefort	74-82	Med	66-72	An authentic Trappist style yeast. Use for Belgian style ales, Dubbels, Tripels, and specialty beers. Fruit character is medium, in between WLP500 (high) and WLP530 (low). This strain benefits from extra oxygenation. Seasonal Availability: Jul - Aug.
WLP545 - Belgian Strong Ale		78-85	Med	66-72	From the Ardennes region of Belgium, this classic yeast strain produces moderate levels of ester and spicy phenolic character. Typically results in a dry, but balanced finish. This yeast is well suited for Belgian dark strongs, Abbey Ales, and Christmas beers.
WLP550 - Belgian Ale	Achouffe	78-85	Med	68-78	Saisons, Belgian Ales, Belgian Reds, Belgian Browns, and White beers are just a few of the classic Belgian beer styles that can be created with this yeast strain. Phenolic and spicy flavors dominate the profile, with less fruitiness then WLP500.
WLP565 - Belgian Saison	Brasserie Dupont (Saison Dupont)	65-75	Med	68-75	May stall, use at higher temps to prevent. Considered the "Dupont" strain.
WLP566 - Saison II	Vieille Provision Saison Dupont and Brasserie de Blaugies	78-85	Med	68-78	Saison strain with more fruity ester production, Fast Fermenter.
WLP568 - Belgian Ale Yeast Blend		70-80	Med	70-80	Belgian style ale and Saison strains. The strains work in harmony to create complex, fruity aromas and flavors. Yeast strain encourages complete fermentation in a timely manner. Phenolic, spicy, earthy, and clove like flavors are also created.
WLP570 - Belgian Golden Ale	Duvel (Moortgart) via McEwans	73-78	Low	68-75	From East Flanders, versatile yeast that can produce light Belgian ales to high gravity Belgian beers (12% ABV). A combination of fruitiness and phenolic characteristics dominate the flavor profile. Some sulfur is produced during fermentation, which will dissipate following the end of fermentation. Does not ferment maltotriose . Determined to be a diastatic strain of Saccharomyces cerevisiae .
WLP575 - Belgian Style Ale Yeast Blend	WLP500, WLP530, WLP550	74-80	Med	68-75	A blend of Trappist type yeast (2) and one Belgian ale type yeast. This creates a versatile blend that can be used for Trappist type beer, or a myriad of beers that can be described as 'Belgian type'.
WLP585 Belgian Saison III		70-74	Med	68-75	Produces beer with a high fruit ester characteristic, as well as some slight tartness. Finishes slightly malty, which balances out the esters. Low levels of clove phenolics. Great yeast choice for a summer Saison that is light and easy-drinking. Seasonal Availability: Jul - Aug. Reported by Richard Preiss of Escarpment Laboratories that WLP585 has the STA1 gene that codes for a diastatic strain of Saccharomyces cerevisiae, but reported that it takes weeks before it hyper-attenuates
WLP590 French Saison Ale		73-80	Med	69-75	Unique yeast strain producing farmhouse-style beers with a phenolic “bite” and moderate ester compounds. Producing a cleaner aroma profile than other farmhouse styles, this yeast is versatile and highly attenuating. Seasonal Availability: May - Jun. Determined to be a diastatic strain of Saccharomyces cerevisiae .
WLP644 Saccharomyces "Bruxellensis" Trois		85%+	Low	70-85	Medium-High alcohol tolerance. This Belgian strain produces a slightly tart beer with delicate characteristics of mango and pineapple. Can also be used to produce effervescence when bottle-conditioning. Formally named Brettanomyces bruxellensis Trois, it was re-classified to be Saccharomyces, and probably S. cerevisiae . White Labs classifies this as a "wild Saccharomyces" . Trois cannot ferment lactose . It does not produce significant amounts of acetic or lactic acid, even under aerobic conditions . Therefore if acid (lactic or acetic) is found in a Trois beer, contamination would be the cause. It also does not produce phenols (POF-), but does produce higher amounts of esters than most strains of S. cerevisiae Approx. 500 million cells per mL; homebrew vials are approx. 17.5 billion cells at 35 mL . PurePitch packages now contain the same pitching rate as other S. cerevisiae White Labs strains (1.5 billion to 3.0 billion cells per mL). One example from their "Yeastman" database for lot # 1035203 (02/19/2017) shows 2.3 billion cells per mL . Determined to be a diastatic strain of Saccharomyces cerevisiae .
WLP700 Flor Sherry Yeast		80-100 (may not be accurate)		70-100	15%+ ABV alcohol tolerance. Report by Johnny Horn for 100% WLP700 in the following characteristics: aroma: slightly savory, slight worcestershire sauce, earthy, cidery. Flavour: sweet nutty caramel, light acidity, honey, apple, brown sugar, strawberry/cherry, dry woody, slightly thin mouthfeel. Has its own odd (but pleasant) character and complexity. Final pH was 3.5, which might indicate a blend with lactic acid bacteria (1g/l aged Fuggles at 60 mins, and 1g/l aged Fuggles at 10 mins). Pitch was 1.0 (M cells / ml / ° P) at 19C and fermentation chamber was set to 21-22C for duration. Final gravity was stable at 1.024 from 1.065 at about 4 weeks, indicating that the advertised attenuation may not be accurate . Can be a slow fermenter on its own. See also the WL FAQ.

Wild Pitch Yeast

Name	Source	Attenuation	Flocculation	Temp°F	Notes
WPY125	Oak tree in Red River Gorge, KY				Sweet and floral aromas are produced by this strain, and it yields a typical Belgian phenolic flavor .

Wyeast

Name	Source	Attenuation	Flocculation	Temp°F	Notes
1214 - Belgian Abbey™		74-78	Med-Low	68-78	A widely used and alcohol tolerant Abbey yeast that is suitable for a variety of Belgian style ales. This strain produces a nice ester profile as well as slightly spicy alcohol notes. It can be slow to start; however, it attenuates well.
1388 - Belgian Strong Ale™	(Suspected) Duvel/McEwans	74-78	Low	64-80	The classic choice for brewing golden strong ales. This alcohol tolerant strain will produce a complex ester profile balanced nicely with subtle phenolics. Malt flavors and aromas will remain even with a well attenuated dry, tart finish. This strain is prone to stalling at approximately 1.035; racking or slight aeration will encourage it to finish fermentation. Determined to be a diastatic strain of Saccharomyces cerevisiae .
1762 - Belgian Abbey II™		73-77	Med	65-75	An excellent yeast strain for use in Belgian dark strong ales. This strain has a relatively “clean profile” which allows a rich malt and distinctive ethanol character to shine. Delicate dried fruit esters can be produced when used at higher fermentation temperatures or in a high gravity wort.
3463 - Forbidden Fruit™	(Suspected) Hoegaarden Verboden Vrucht	72-76	Low	63-76	A widely used strain in the production of Witbier and Grand Cru. This yeast will produce spicy phenolics which are balanced nicely by a complex ester profile. The subtle fruit character and dry tart finish will complement wheat malt, orange peel and spice additions typical of Wits. Available from April through June 2017.
3522 - Belgian Ardennes™		72-76	High	65-76	One of the great and versatile strains for the production of classic Belgian style ales. This strain produces a beautiful balance of delicate fruit esters and subtle spicy notes, with neither one dominating. Unlike many other Belgian style strains, this strain is highly flocculent and results in bright beers.
3538 - PC Leuven Pale Ale		75-78	High	65-80	This vigorous top fermenting Belgian style strain produces a distinct spicy character along with mild esters. Phenolics developed during fermentation may dissipate with conditioning. 3538 is an excellent choice for a wide variety of Belgian beer styles. Private Collection for Spring 2015 (available April-June 2015).
3711 - French Saison		77-83	Low	65-77	Peppery, spicy and citrusy. This strain enhances the use of spices and aroma hops, and is extremely attenuative but leaves an unexpected silky and rich mouthfeel. See this MTF thread for fermentation tips. Determined to be a diastatic strain of Saccharomyces cerevisiae . This strain has been rumored to originate from the Brasserie Thiriez brewery , however, Daniel Thiriez claims that his brewery's strain of yeast is not the same as WY3711 .
3724 - Belgian Saison™	Dupont	76-80	Low	70-95	It is very tart and dry on the palate with a mild fruitiness. Expect a crisp, mildly acidic finish that will benefit from elevated fermentation temperatures. Notorious for a rapid start, only to stick. Fermentation will finish, at least 90°F. The same or very similar to the "Dupont" strain. This strain was sequenced by Lance Shaner of Omega Yeast Labs as possibly being the species S. boulardii; it is not known if other labs who offer the "Dupont" strain offer the same isolate because bottles of Dupont saison have reportedly been found to have multiple and varying strains over time . Determined to be a diastatic strain of Saccharomyces cerevisiae .
3725 - Biere De Garde	Soy-Erezée, Belgium / Fantôme	74-79	Low	70-84	Low to moderate ester production with subtle spiciness. Malty and full on the palate with initial sweetness. Finishes dry and slightly tart. Ferments well with no sluggishness. Determined to be a diastatic strain of Saccharomyces cerevisiae . Available from April through June 2017.
3726 - Farmhouse Ale	Blaugies, Belgium	74-79	Med	70-84	This strain produces complex esters balanced with earthy/spicy notes. Slightly tart and dry with a peppery finish. A perfect strain for farmhouse ales and saisons. Determined to be a diastatic strain of Saccharomyces cerevisiae . Available from July through September 2015.
3739 - Flanders Golden Ale™		74-79	Med-Low	64-80	3739-PC is a well-balanced strain, producing moderate levels of both fruity esters and spicy phenols while finishing dry with a hint of malt. Robust alcohol and temperature tolerance plus strong attenuation make it a good candidate for high-gravity fermentations. Determined to be a diastatic strain of Saccharomyces cerevisiae . Available from April through June 2016.
3787 - Trappist High Gravity™	(Suspected) Westmalle	74-78	Med	64-78	A classic strain for brewing Belgian Dubbel or Belgian Tripel. This Abbey strain produces a nice balance of complex fruity esters and phenolics, making it desirable for use in other Belgian style ales as well. A flocculent, true top cropping yeast (additional headspace is recommended), that will work over a broad temperature range. This strain makes a great Belgian style “house” strain.
3822 - Belgian Dark Strong Ale™		74-79	Med	65-80	Oud Bruin/Flanders Brown, Fruit beers, Belgian Golden and Dark Strong Ales, Kriek and Framboise, Belgian Specialty Ale Profile: 3822-PC is a unique Saccharomyces strain which produces spicy, phenolic and distinctly tart aromas and flavors, which can be increased through warmer fermentation temperatures. Very tart and dry on the palate, complemented well by blending with fruit. Available from April through June 2016.
3864 - Canadian/Belgian Ale™		74-79	Med	65-80	This alcohol tolerant strain produces complex and well-balanced Belgian Abbey style ales. Banana and fruit esters are complemented nicely with mild levels of phenolics and hints of acidity. Ester levels may be elevated by increasing gravity and fermentation temperatures. May produce some sulfur at cool fermentation temperatures. Determined to be a diastatic strain of Saccharomyces cerevisiae . Available from April through June 2016.
3942 - Belgian Wheat™	(Suspected) De Dolle	72-76	Med	64-74	Isolated from a small Belgian brewery, this strain produces beers with moderate esters and minimal phenolics. Apple, bubblegum and plum-like aromas blend nicely with malt and hops. This strain will finish dry with a hint of tartness.
3944 - Belgian Witbier™		72-76	Med	62-75	This versatile Witbier yeast strain can be used in a variety of Belgian style ales. This strain produces a complex flavor profile dominated by spicy phenolics with low to moderate ester production. It is a great strain choice when you want a delicate clove profile not to be overshadowed by esters. It will ferment fairly dry with a slightly tart finish that compliments the use of oats, malted and unmalted wheat. This strain is a true top cropping yeast requiring full fermenter headspace of 33%.

Starters

1. "Optimizing Yeast Starters" by Dr. Bryan Heit.
2. AHA guide to making yeast starters.
3. Mark Van Ditta's "shaken, not stirred" starter method.

See also:

• Fermentis 2018 data on re-hydration vs pitching direct for active dry yeast. See also recommendations from Lallemand.
• For information on mixed culture starters, see Mixed Culture Starters.

Storage

For long term storage (3 months to potentially 2+ years), slants are a good option. For instructions on how to make slants at home capable of storing any microbe for potentially 2+ years, see Bryan's video on Sui Generis Brewing (requires a pressure cooker).

• MTF thread on freezing yeast for storage, with link to HBT article.
• "Maintaining A Healthy Yeast Bank Long Term", article on HBT.
• Bryan of Sui Generis blog guide to freezing & refrigerating yeast for homebrewers:

See Also

Additional Articles on MTF Wiki

• Wort Souring
• Lactobacillus
• Pediococcus
• Brettanomyces
• Debaryomyces
• Spontaneous Fermentation
• Kveik

MTF Threads

• Study that shows heat shock increases glycerol production.

External Resources

• Maltose Falcons Guide To Saisons - Saison yeast profiles
• Coming Clean: A New Method of Washing Yeast with Chlorine Dioxide.
• Esters - Table of esters and their smells.
• The Saccharomyces family, by Lars Garshol.
• VLB Berlin pure yeast cultures.
• Yeast Strain Comparison Chart (White Labs, Wyeast) - information by Kristen England on Mr. Malty website.
• In depth article by Tracy Aquilla on yeast respiration, "How Yeast Use Oxygen".
• A blog article about brewing with Saccharomyces paradoxus by Matt Humbard on A Ph.D. in Beer blog.
• "Here It Is, the Genetic Family Tree of Beer", article on the Verstrepen/White Labs paper on the family tree of yeast.
• YouTube taste comparison of three Yeast Bay Saison cultures, and tips from Drew Beechum on fermenting with saison yeast.
• Wine Strain Chart from Winemakers.com.
• Scott Labs wine yeast inventory, with descriptors of each yeast for thiols, mouthfeel, etc.
• Charlie Bamforth overview of biochemistry of yeast flavors on BeerSmith Podcast; 01/26/2018.