Changes

Sour fermentations require at least one Lactic Acid Bacteria (LAB), such as [[Lactobacillus]] or [[Pediococcus]], and at least one yeast such as [[Saccharomyces]] or [[Brettanomyces]]. Many yeast companies offer [[Mixed Cultures]] that provide all of the organisms microorganisms necessary to make a sour beer. The results of these commercial mixed cultures can be as varied as the cultures themselves. For example some of these commercial mixed cultures produce lightly tart beer that may exhibit less funky flavors than other cultures. This is dependent on what types of microbes are in the mixed culture, what their ratios are, how old the cultures are, and of course what methods the brewer uses to encourage or discourage certain flavors. The brewer must realize understand that all of these microbes are complex organisms (some more complex than others), and not . Not only due do different species behave differently and produce different resultsunder different conditions, but different strains of the same species also can also behave differently and produce greatly different resultsunder different conditions. Just as strains of Saccharomyces cerevisiae all produce different results in clean beers (e.g., California Ale yeast versus Belgian Ale yeast), strains of Lactobacillus spp. and especially Brettanomyces spp. can also create completely different resultsvary widely.

Beer styles that use can be brewed using this method include [[Berliner Weissbier]], [[Flanders Red Ale]], [[Oud Bruin]], and the subcategories of [[American Wild Ale]], which includes [[Mixed-Fermentation Sour Beer]] and [[Soured Fruit Beer]] <ref>[http://www.bjcp.org/docs/2014%20BJCP%20Style%20Guidelines%20%28DRAFT%29.pdf BJCP 2014 Style Guidelines Draft.]</ref>. European sour styles such as [[Lambic]], [[Gueuze]], and [[Fruit Lambic]], technically can only be produced by [[Spontaneous Fermentation]]. [[Flanders Red Ale]] and [[Oud Bruin]] styles can be brewed using pure cultures, but can also be brewed using spontaneous fermentation or a mix of using pure cultures and spontaneous fermentation.