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Wort Souring

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==Contamination Concerns==
Contamination issues seem to be the biggest challenge with pre-souring wort with ''Lactobacillus''. This is because ''Lactobacillus'' does not fully ferment wort by itself (see [[100%25_Lactobacillus_Fermentation|100% ''Lactobacillus'' fermentation]]). When yeast fully ferments wort into beer, alcohol, hops, and a low pH all work together to help prevent other microorganisms from contaminating the beer (although contamination can certainly happen with beer spoilage microbes such as ''Brettanomyces'', ''Pediococcus'', etc.) <ref>[http://suigenerisbrewing.blogspot.com/2014/02/fact-or-fiction-can-pathogens-survive.html "Fact or Fiction? Can Pathogens Survive in Beer?" Sui Generis Blog. 02/18/2014. Retrieved 11/10/2016.]</ref>. When fermenting with ''Lactobacillus'' by itself, either no alcohol is produced or not enough alcohol is produced to have an antimicrobial effect. Usually hops are not used when souring wort with ''Lactobacillus'' because even small amounts of hops completely inhibit most commercial strains, so other microbes that are sensitive to hops are also not inhibited. The high available sugars , warm temperatures typically used in souring wort, and a lack of alcohol/hops therefore increases increase the chances for contamination during souring wort with ''Lactobacillus''.
Contaminations can have a variety of effects on soured wort depending on the type of microbe(s) that caused the contamination. One typical off-flavor in kettle sour beers is [[Butyric_Acid|butyric acid]], which is in and smells like human vomit. Although the exact source of butyric acid in kettle soured beers has not been identified scientifically that we know of, butyric acid is produced by anaerobic contaminates and '''not''' when ''Lactobacillus'' is exposed to oxygen (see [[Lactobacillus#Effects_of_Oxygen|Effects of Oxygen on ''Lactobacillus'']] and [[Butyric_Acid|butyric acid]]). [[Isovaleric_Acid|Isovaleric acid]] is another off-flavor that can be produced by both anaerobic and aerobic contaminates.

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