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'''''Lactobacillus''''' (often referred to by brewers as "Lacto") is a genus of Gram-positive, rod-shaped lactic acid bacteria (LAB) which produces acidity and sour flavors in the form of lactic acid and [[Lactobacillus#Sugar_Utilization_and_Secondary_Metabolites|secondary metabolites]] found in lambics, Berliner Weiss, sour brown ales, and gueuze. All ''Lactobacillus'' species are facultative anaerobes, which means they grow anaerobically but can also grow in the presence of oxygen and use oxygen to some degree <ref name="todar_lactics4"></ref>. They [https://www.researchgate.net/post/How_to_prepare_spore_forming_media_for_lactobacillus do not form spores]. There are more than 100 species, many of which are found in the human gastrointestinal track <ref name="todar_lactics4">[http://textbookofbacteriology.net/lactics_4.html ''Lactic Acid Bacteria''. Todar's Online Texbook of Bacteriology. Kenneth Todar, PhD. Pg. 4. Retrieved 07/28/2015.]</ref><ref name="Todar_nutgro4">[http://textbookofbacteriology.net/nutgro_4.html ''Nutrition and Growth of Bacteria''. Todar's Online Texbook of Bacteriology. Kenneth Todar, PhD. Retrieved 07/28/2015.]</ref>. In addition to beer, some species of ''Lactobacillus'' are also used to ferment yogurt, cheese, sauerkraut, pickles, wine, cider, kimchi, cocoa, and kefir <ref>[https://en.wikipedia.org/wiki/Lactobacillus ''Lactobacillus''. Wikipedia. Retrieved 07/28/2015.]</ref>. It might be possible for ''[[Lactobacillus]]'' can to form a [[Pellicle|pellicle]] (need according to Dr. Matt Humbard; see referenceand [https://www.facebook.com/groups/MilkTheFunk/posts/8967638479930953/?comment_id=8967994039895397 this opinion piece by Dr. Bryan Heit on MTF on why it is difficult to find any scientific sources for pellicles]); however, this has not been scientifically proven as far as we know <ref name="matt">[http://phdinbeer.com/2015/01/30/beer-microbiology-what-is-a-pellicle/ Beer Microbiology – What is a pellicle? A PhD in Beer blog. Dr. Matt Humbard. 01/30/2015. Retrieved 04/26/2015.]</ref>. See ''[[Pediococcus]]'', ''[[Brettanomyces]]'', ''[[Saccharomyces]]'', [[Mixed Cultures]], [[Kveik#Commercial_Availability|Kveik]], and [[Nonconventional Yeasts and Bacteria]] charts for other commercially available cultures. See the [[Wort Souring]] and [[Mixed Fermentation]] pages for brewing techniques with ''Lactobacillus''. See the [[Alternative Bacteria Sources]] section for culturing ''Lactobacillus'' from grains, yogurt, probiotics, and other sources.
==Introduction of Characteristics and Taxonomy==
! Lab Name !! Product Name !! Taxonomy !! CO2 Producer (Hetero/Homo) !! Starter Note !! Fermentation/Other Notes
|-
| [[Bootleg Biology]]/[[Spot Yeast]] || Sour Weapon L || ''Lactiplantibacillus plantarum'' (blended strains) || Facultatively heterofermentative || || Drops the pH of wort quickly. At 98F, trial batches dropped the pH of wort to 3.0 after just 24 hours. When pitched at 84F, pH should reach 3.5 in 24 hours. Ideal to use for acidifying wort for quick/kettle sours, and is also very effective when co-pitched with a yeast strain. As with any Lactobacillus culture, we do not recommend using in worts with <s>10 or more IBUs</s> any hops (this is the up to date recommendation from Jeff Mello of Bootleg Biology; any amount of hops will inhibit ''L. plantarum'' in general) <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/2800217156673147/?comment_id=2800400083321521&reply_comment_id=2804474432914086&comment_tracking=%7B%22tn%22%3A%22R%22%7D Jeff Mello. Milk The Funk Facebook thread on the lack of IBU tolerance of ''L. plantarum'' and Sour Weapon L. 07/23/2019.]</ref> as that will prevent significant souring. Isolated from traditional Norwegian Kveik <ref>[http://bootlegbiology.com/2017/06/27/new-culture-pre-sale-july-5-featuring-mtf-mega-blend-sour-weapon-l/ "New Culture Pre-Sale July 5: Featuring MTF Mega Blend & Sour Weapon L!" Bootleg Biology website. 06/27/2017. Retrieved 06/05/2017.]</ref>.
|-
| [[Brewing Science Institute]] || L. brevis || ''Levilactobacillus brevis'' || Heterofermentative || || Shipped during log phase, so recommended to use within 2 to 3 days of receiving. Unlike yeast, BSI sells bacteria by volume, and will sell a specific volume for the number of BBL's the brewer is souring. Store at room temperature, not cold. Optimal temperature for fermentation is 102-105°F. Bacteria is half the price of yeast. Commercial pitches only; not listed on their catalog, but is carried in stock. BSI does not have IBU tolerance data, but there has been at least one report of it being tolerant of up to 20 IBU <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/2147198278641708/?comment_id=2147921045236098&reply_comment_id=2148812765146926&comment_tracking=%7B%22tn%22%3A%22R%22%7D John Rowley, Andrew Deming, and Dan Ramos. Milk The Funk Facebook group thread on BSI brevis. 06/26/2018.]</ref>.
| [[Brewing Science Institute]] || L. delbrueckii || ''Lactobacillus delbrueckii'' || Homofermentative || || A Lactobacillus bacteria that produces a clean lactic sourness.
|-
| Chr. Hansen || Harvest LB-1 || ''Lactiplantibacillus plantarum'' || Faculatative Heterofermentative || The culture is ready for inoculation directly in all beverage bases without previous reactivation (freeze dried) || Harvest LB-1 is a freeze dried concentrated pure culture of ''Lactobacillus L. plantarum''. The culture has been selected to ensure a fast and safe acidification of cereal bases, vegetable juices and other sugar beverage bases. Can acidify wort to pH 3.2 and should allow brewers to decrease pH from 5.5 to 3.5 in ~ 16 hours. Temp range of 70 – 100 ⁰F. Tolerates 8 IBU. Commercial only sizes available through [https://www.gusmerenterprises.com/catalog/brewing/brewing-processing-aids/sour-beer/harvest-lb-1/ Gusmer Brewing]. <ref>[https://www.gusmerbeer.com/wp-content/uploads/sites/8/2019/04/PI_GLOB_HarvestLB-1_718316_EN.pdf "Harvest LB-1". Chr. Hansen. Retrieved 12/19/2019.]</ref><ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/3140287979332728/?comment_id=3140612629300263&reply_comment_id=3140685999292926 Chris Webster. Sales at Gusmer. Milk The Funk Facebook thread on Chr Hanson L. plantarum. 12/19/2019.]</ref>
|-
| [[Community Cultures Yeast Lab]] || Lactobacillus brevis || ''Levilactobacillus brevis'' || Heterofermentative || || For traditional and kettle souring methods, produces high lactic acid. Suggested for use in wort under 5-10 IBUs. Fermentation Temperature: 75-105F.
| [[Fermmentos Labs]] (Brazil - CLOSED) || FB12 Lactos || ''Lactobacillus delbruekii'' and ''Lacticaseibacillus rhamnosus'' || Homofermentative || || Designed for kettle souring. Optimal temperatures of 25-30°C <ref name="fermmentos_catalog_2017" />.
|-
| [[GigaYeast]] (CLOSED) || GB110 || ''Lactobacillus delbrueckii''? <ref>[https://www.facebook.com/GigaYeast/posts/565914926872849?comment_id=567669393364069&offset=0&total_comments=1¬if_t=feed_comment From Gigayeast, Inc. on Facebook, 12/3/2014: "Appears to be L. delbrueckii."]</ref> || Heterofermentative || For a 5 gallon batch of beer use 2 liters at 1.040 with high quality yeast nutrient. Keep as close to 86°F (30°C) as possible for 3-4 days with frequent rousing (no stir plate) <ref>Personal Communication with Jim Thompson.</ref>. || Lactic Acid Bacteria are inhibited by hops, high gravity and low temperatures. You can adjust sourness by increasing or decreasing these variables. More than 7 IBU, gravity above 1050 or temps below 65 F will increase the time to sour or lead to reduced overall souring. Contains ~200 billion cells per homebrew pitch <ref name="sbb2.0"></ref>.
We recommend brewing with GB110 in one of three ways. I) “Hot Start”: Pitch GB110 to wort at 98 F with little or no hops for 48-72 hrs. Wort may be soured before kettle boil or after. If soured before kettle boil, boil with hop additions as usual. If soured after kettle boil cool wort and pitch yeast. II) “Co-Pitch”: Pitch GB110 into a primary with yeast of your choice at 68-72 F. Wort that is less than 1050 and 7 IBU will typically be very sour in 2-3 weeks. III) “Secondary”: Pitch GB110 after primary fermentation for an aged sour. Souring by this method typically requires several months. Adding simple sugars or fruit etc. will enhance souring in the secondary <ref>[http://www.gigayeast.com/fast-souring-lacto GigaYeast Webpage. Retrieved 7/22/2015.]</ref>. Sometimes referred to as GigaYeast's "Fast Acting Lacto". This strain is hop sensitive <ref name="steve_smith">[https://www.facebook.com/groups/MilkTheFunk/permalink/1068326413195572/?comment_id=1069411906420356&offset=0&total_comments=12&comment_tracking=%7B%22tn%22%3A%22R%22%7D Conversation with Steve Smith of GigaYeast on MTF. 05/08/2015.]</ref>.
| [[Inland Island Brewing & Consulting|Inland Island Yeast Laboratories]] || INISBC-932 || ''Limosilactobacillus fermentum'' || Heterofermentative || ||
|-
| [[Jasper Yeast]] || Lactobacillus plantarum JY-LPLANT || ''Lactiplantibacillus plantarum'' || Facultatively heterofermentative || || Ideal for kettle souring. Optimum temperature is 100°F-110°F. L. plantarum is hop sensitive, we advise not to use any hops until souring is satisfactory. <ref name="Jasper_Lacto">[https://jasperyeast.com/bacteria "Available Bacteria". Jasper Yeast Website.]</ref>
|-
| [[Jasper Yeast]] || Lactobacillus brevis JY-LBREV || ''Levilactobacillus brevis'' || heterofermentative || || Ideal for kettle souring. works well at 95°F-105°F. <ref name="Jasper_Lacto"/>
|-
| [[Jasper Yeast]] || Lactobacillus blend || ''Lactiplantibacillus plantarum'' and ''Levilactobacillus brevis'' || Facultatively heterofermentative/heterofermentative || || Ideal for kettle souring. Optimum temperature is 95°F-110°F. L. plantarum is hop sensitive, we advise not to use any hops until souring is satisfactory. <ref name="Jasper_Lacto"/>
|-
| [[Jasper Yeast]] || JY-LACID || ''Lactiplantibacillus acidophilus''|| Homofermentative || || Optimum temperature is 95°F-105°F. <ref name="Jasper_Lacto"/>
|-
| Lallemand || WildBrew Sour Pitch || ''Lactiplantibacillus plantarum'' <ref>[https://www.facebook.com/Lallemandyeasts/photos/a.941604692537326.1073741829.939455986085530/1656901501007638/?type=3&comment_id=1657229347641520&reply_comment_id=1657231934307928&comment_tracking=%7B%22tn%22%3A%22R5%22%7D Post on the Lallemand Facebook page. 09/22/2017. Retrieved 09/22/2017.]</ref> || Facultatively heterofermentative || || See [https://www.facebook.com/groups/MilkTheFunk/permalink/1790290834332456/ this information from Scott Lucas on MTF]. This culture comes in a dry (desiccated) format. Although the [http://www.lallemandbrewing.com/product-details/wildbrew-sour-pitch manufacturer's website] claims this strain is tolerant of 4 IBU, we recommend that brewers treat this strain like any other strain of ''L. plantarum'' and do not expose it to any hops until the desired acidity has been produced (for example, see [[Wort Souring]]). Recommended temperature: 95-100°F (35-38°C) <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1882643148430557/?comment_id=1883360638358808&reply_comment_id=2017197581641779&comment_tracking=%7B%22tn%22%3A%22R9%22%7D Caroline Smith (rep from Lallemand). Milk The Funk Facebook group regarding Lallemand WildBrew Sour Pitch. 03/09/2018.]</ref><ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1988756664485871/?comment_id=1990170714344466&reply_comment_id=2017220451639492&comment_tracking=%7B%22tn%22%3A%22R9%22%7D Caroline Smith (rep from Lallemond). Milk The Funk Facebook group regarding Lallemand WildBrew Sour Pitch and IBU tolerance. 03/09/2018.]</ref>.
| [[RVA Yeast Labs]] || RVA 600 || ''Lacticaseibacillus rhamnosus'' || Homofermentative || No starter necessary per RVA || Homofermentative Lacto strain found in probiotics; sensitive to hops; does well at room temperature.
|-
| [[SouthYeast Labs]] (CLOSED) || Lactobacillus 1 || Unknown || Heterofermentative || || Source: Spontaneously infected beer (South Carolina). Best suits Light sours, gose, farmhouse saison (medium/high acidity).
|-
| [[SouthYeast Labs]] (CLOSED) || Lactobacillus 2 || Unknown || Homofermentatative || || Source: Prickly pear fruit (South Carolina). Best suits strong sours, and lambic (high acidity).
|-
| [[The Yeast Bay]] || Lactobacillus Blend || ''Lactiplantibacillus plantarum'', and 2 strains of ''Levilactobacillus brevis'' || Heterofermentative || || The Lactobacillus Blend includes three strains: ''Lactobacillus plantarum'', ''Lactobacillus brevis'' and a second strain of ''Lactobacillus brevis'' isolated from an accidentally soured blonde ale from a Mexican craft brewery. Quickly produces acidity across a wide range of temperatures. It can be used on its own for kettle souring prior to pitching yeast to create acidity quickly, or co-pitched with yeast to create sourness over time. It will produce a pronounced and rounded acidity. The Yeast Bay recommends holding the IBU on the low end (< 2-3) if you'd like to use this blend to create acidity in a shorter time frame. Higher IBUs may result in souring, but the strain of ''L. brevis'' isolated from the Mexican craft brewery is hop tolerant up to about 15-20 IBU. Temperature: 70-90°F. Cell count: 50-80 million cells/mL (1.75-2.8 billion cells for 35 mL homebrew vials) <ref name="WL_cellcounts"></ref><ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1280135442014667/?comment_id=1280341068660771&reply_comment_id=1280498695311675&comment_tracking=%7B%22tn%22%3A%22R1%22%7D Conversation with Nick Impellitteri on MTF regarding TYB Lactobacillus Blend cell counts. 04/08/2016.]</ref>. Recommended temperature range for fastest acid production for kettle souring is 85-90°F, although if kept in the 70's it should produce good acidification in 48-72 hours. A major drop off of in acid production is seen above 90°F <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1616265398401668/?comment_id=1617001948328013&comment_tracking=%7B%22tn%22%3A%22R%22%7D Impellitteri, Nick. Milk The Funk Facebook group. 03/17/2017.]</ref>.
| [[The Yeast Bay]] || TYB282 || ''Lactiplantibacillus brevis'' || Heterofermentative || || TYB282 is a single strain of Lactobacillus brevis isolated out of an unintentionally soured golden ale produced by a Mexican craft brewery.
This strain produces a clean lactic acidity (down to ~pH 3.16-3.18) in unhopped wort within 36 hours at a temperature of ~72-77 F. The higher the temperature (up to 90 F is what we've tested), the faster the acid production. Recommended for kettle souring, as it grows rather quickly and produces acidity fast with no detectable off flavors. The Yeast Bay has tested this strain at ~20 IBU and it was able to reduce the pH of beers down to 3.30 pH when co-pitched with a farmhouse yeast. It might create acidity at higher IBU's (Nick suggests maybe up to 30 IBU); however, this has not been tested yet <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/2907190232642505/?comment_id=2907235245971337 Nick Impellitteri. Milk The Funk Fcaebook group post on TYB282 hop tolerance. 09/12/2019.]</ref>. Temperature: 70-90 ºF.
|-
| [[WHC Lab]] || Lactobacillus helveticus - Tangy Dehydrated Bacteria || ''Lactobacillus helveticus'' || Homofermentative || || Described as producing "citrus" flavor. Use no hops. Ferment between 36°C to 42°C for quick souring.
|-
| [[WHC Lab]] || Lactobacillus plantarum - Dehydrated Bacteria || ''Lactiplantibacillus plantarum'' || Facultatively heterofermentative || || Described as producing "citrus" flavor. Use no hops. Ferment between 34°C to 36°C for quick souring.
|-
| [[White Labs]] || WLP677 || ''Lactobacillus delbrueckii'' (might be misidentified <ref>[http://masterbrewerspodcast.com/085-lactic-acid-bacteria-case-study Tim Lozen. Master Brewers Association podcast interview on lactic acid bacteria case study. 04/23/2018.]</ref>) || Heterofermentative <ref name="mtf_wiki_shaner">[http://www.milkthefunk.com/wiki/100%25_Lactobacillus_Fermentation Milk The Funk Wiki. 100% Lactobacillus Fermentation Test by Lance Shaner.]</ref><ref name="tmf_cultures">[http://www.themadfermentationist.com/p/commercial-cultures.html ''Commercial Brettanomyces, Lactobacillus, and Pediococcus Descriptions''. The Mad Fermentationist Blog. Michael Tonsmeire. Retrieved 3/4/2015.]</ref> || no stir plate, room temp ||Incubate at > 90°F and < 117°F for 5-7 days for greater lactic acid production. Cell count: 50-80 million cells/mL (1.75-2.8 billion cells in a 35 mL homebrew vial) <ref name="WL_cellcounts">Private correspondence with White Labs Customer Service and Dan Pixley. 10/29/2015.</ref>. Not a good strain for kettle souring, but can produce a "soft" acidity over a longer period of time <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1212455192116026/?comment_id=1212475888780623&reply_comment_id=1212476575447221&comment_tracking=%7B%22tn%22%3A%22R3%22%7D Conversation with Andrew Addkison on MTF. 01/12/2016.]</ref>. White Labs claims that it is tolerant to up to 20 IBU, although growth starts to become inhibited at 15 IBU <ref name="WL_datasheet" /><ref>[http://www.themadfermentationist.com/p/commercial-cultures.html "Commercial Brettanomyces, Lactobacillus, and Pediococcus Descriptions; Commercial Yeast Laboratories." The Mad Fermentationist blog. Michael Tonsmeire. Retrieved 12/12/2016.]</ref>. Generally heat tolerant, but sours faster between 100-110°F <ref name="WL_datasheet">[http://www.whitelabs.com/sites/default/files/R%26D%20Wild%20Yeast%20and%20Bacteria%20Experiments_2.pdf "R&D Wild Yeast and Bacteria Experiments". White Labs data sheet. Retrieved 05/16/2017.]</ref>
</blockquote>
Hop tolerance is not only species dependent, but is also strain dependent. For example, a dissertation by F.J. Methner measured the pH drop of wort that started at a pH of 5.55 from day 3 to day 14 for several strains of ''L. brevis'' at different IBU levels (7,9,11,13 and 18 IBU's). One strain of ''L. brevis'' eventually got down to a pH of 3.8 at day 14 with 7 IBU's, while another strain got down to 3.3 pH at day 14 (with other strains in-between those numbers). At 18 IBU, the relatively hop intolerant ''L. brevis'' strain got down to only 4.2 pH, while another strain got down to 3.7. In general, the higher the IBU, the slower the pH drop. Interestingly, another species called ''L. coryniformis'' was shown to be more hop tolerant than ''L. brevis''. ''L. coryniformis'' dropped the 18 IBU wort down to 3.6 pH over 14 days <ref name="Methner">[https://www.facebook.com/groups/MilkTheFunk/permalink/1537381402956735/ Methner, F.D. Uber Die Aromabildung beim berliner weissebier unter besonderer berucksichtigung von sauren and estern (data reported and translated by Benedikt Koch on Milk THe The Funk Facebook group). 1987.]</ref>. In a separate study, one strain of ''Lacticaseibacillus paracasei'' subsp. ''paracasei'' was able to remain viable in 40 IBU beer <ref>[https://www.sciencedirect.com/science/article/abs/pii/S0963996924011104 Lucas Borges Martins da Silva, Katy Vieira Arruda, Juliana Yumi Suzuki, Marcos Edgar Herkenhoff. Survival of the probiotic strain Lacticaseibacillus paracasei subsp. paracasei F19 in high-hopped beers. Food Research International, 2024, 115040, ISSN 0963-9969, https://doi.org/10.1016/j.foodres.2024.115040.]</ref>
Methner's data is shown below; graphs created by Benedikt Koch <ref name="Methner" />. Y axis = pH, X axis = days.
== Commercially available Lactobacillus strains and their pH change over time ==
All data provided by [http://phdinbeer.com/2015/08/05/beer-microbiology-lactobacillus-ph-expeirment/ Matt Humbard]. Similar results were reported by Lance Shaner's [[Lactobacillus_Fermentation|100% Lactobacillus Fermentation]] experiment. See also the associated [https://byo.com/article/brewing-with-lactobacillus/ write up in BYO Magazine].
=== pH change at 86°F ===
====100% ''Lactobacillus'' Fermentation====
Lance Shaner's experiment on testing [[Lactobacillus_Fermentation|100% Lactobacillus Fermentation]] showed that '''pure cultures''' of WLP677, WLP672, Wyeast 5335, Wyeast 5223-PC, and the ''L. plantarum'' from Omega Yeast OYL-605, could not fully attenuate a 1.037 SG wort. The most attenuative ''Lactobacillus'' culture, WLP677, was only able to attenuate down to 1.03255 SG. It is likely that all species and strains of ''Lactobacillus'' available to brewers cannot fully attenuate wort. In addition, this study showed at most a 0.29% ABV in 100% ''Lactobacillus'' fermentations (attributed to WLP677). See [[Lactobacillus_Fermentation|100% Lactobacillus Fermentation]] for more information. If a higher attenuation is achieved, cross contamination of yeast is most likely the cause. Thomas Hübbe's masters thesis also supports that ''Lactobacillus'' attenuates less than 10% of the sugars in wort <ref name="Hubbe"></ref>.
The amount of CO2 produced is very small in heterofermentative species. Lance Shaner of Omega Yeast Labs noted that although ''L. brevis'' is classified as obligatory heterofermentative, the human eye cannot detect any CO2 production in the Omega Yeast Lactobacillus blend (OYL-605). Lance still needs to test this blend to see if it produces any CO2 at all. There have been reliable reports of pure ''Lactobacillus brevis'' cultures producing a layer of bubbles on the surface of wort if roused <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1354678291227048/?comment_id=1354678411227036&reply_comment_id=1355288821165995¬if_t=group_comment_reply¬if_id=1468974761019794# Conversation with Richard Preiss on MTF regarding pure Lactobacillus fermentation. 07/19/2016.]</ref>. It is clear though that any type of ''Lactobacillus'', regardless of whether it is heterofermentative or homofermentative, cannot produce a krausen. Krausens are sometimes seen even with the use of commercially available ''Lactobacillus'' cultures and good sanitation techniques. If a krausen develops in wort when it is the only culture that is pitched, this is indicative of cross-contamination of ''Saccharomyces'' or ''Brettanomyces'' in either the wort or the ''Lactobacillus'' culture itself <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1083842231643990/?comment_id=1084646124896934&offset=0&total_comments=26&comment_tracking=%7B%22tn%22%3A%22R8%22%7D Discussion with Lance Shaner on MTF. 6/7/2015.]</ref>. In addition to this, heterolactic fermentation by ''Lactobacillus'' can only produce 10-20% of the ethanol that Saccharomyces can produce <ref name="PhysioLacto">[http://phdinbeer.com/2015/04/13/physiology-of-flavors-in-beer-lactobacillus-species/ Humbard, Matt. Physiology of Flavors in Beer – Lactobacillus Species. Retrieved 6/14/2015.]</ref>, therefore a high level of attenuation cannot be achieved by ''Lactobacillus'' and is again a sign of cross contamination by yeast. Take a gravity reading and if the wort gravity has dropped more than 1°P (.004 specific gravity points) then this is due to a yeast fermentation.
An in-house experiment by Bell's Brewery which was presented at the MBAA Conference 2017 by Timothy Lozen reported slightly higher amoutns of ABV from a few species of ''Lactobacillus''. Out of 7 different species of ''Lactobacillus'' that were tested, ''L. bucherni'' (White Labs) produced the most alcohol at 0.64% ABV. ''L. rossiae'' (White Labs) and ''L. brevis'' (Bell's Brewery) produced around 0.4% ABV. ''L. delbruekii'' subsp. ''bulgaricus'' (ATCC #11842) produced around 0.5% ABV. The other strains, which were ''L. delbruekii'' subsp. ''lactis'' (ATCC #12315), ''L. casei'' (White Labs), and ''L. plantarum'' (Goodbelly) produced 0.1% or lower ABV <ref name="lozen_2017" />.
* See also [[Lactobacillus_Fermentation|100% Lactobacillus Fermentation]].
===Primary/Secondary Metabolites===