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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==
| [[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.
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| [[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.
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| [[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>
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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.