Changes

==Finishing Mixed Fermentations==

Reusing a sour yeast cake can often provide great results. Brewers have reported success re-pitching on very old yeast cakes (2+ years) without getting off flavors from yeast autolysis. After several months, ''[[Saccharomyces]]'' tends to die off due to the low pH in a sour beer. The bacteria and ''[[Brettanomyces]]'' tend to survive the lower pH, and their cell counts can be high in even an old yeast cake (interestingly, ''Brettanomyces'' remains more viable over time if it was co-fermented with ''S. cerevisiae'' than if it was fermented by itself; i.e. [[100%25_Brettanomyces_Fermentation|100% ''Brettanomyces'' beers]] <ref name="Hubbe"></ref>). By pitching new wort on an old sour yeast cake, these microbes (particularly the [[Lactobacillus]]) have access to the simple sugars in the wort <ref>[http://www.themadfermentationist.com/2009/11/brewing-sour-beer-at-home.html Tonsmeire, Michael. The Mad Fermentationist. Brewing Sour Beer at Home. Last paragraph in the "Inoculation" section. Retrieved 2/19/2015.]</ref>. Using a young yeast cake is also a viable option, and may carry over more surviving ''Saccharomyces'' cells as well as more viable cells of the other various microbes. In general, washing the yeast cake is not necessary. The beer itself can also be used as an inoculate and might be more desirable so as to avoid trub. If the beer has sat in a barrel ''Acetobacter'' and other unwanted microbes might be more present on the surface of the pellicle, and would remain after racking the beer out of the barrel, so some professional brewers advise using beer as an inoculate for this reason <ref>[https://youtu.be/IGzoh4brILA?t=52m30s Yakobson, Chad. Interview on Craft Commander. 12/20/2016. Retrieved 12/22/2016.] (~52 mins in)</ref>.

As with all methods, the species and strains of the microbes being used should always be taken into consideration. Experimentation and repeated processes should be carefully employed by the brewer in order to find the best results for their cultures. For example, using different strains of ''Saccharomyces cerevisiae'' as the primary fermenter could produce widely different results, and the use of 10-30 IBU's in the wort can be used to inhibit the lactic acid bacteria if they become too strong and produce too much acidity. If the original beer was very acidic, it might also be helpful to make an unhopped starter with a portion of the yeast cake to increase the viability of the lactic acid bacteria and ''Brettanomyces'', although in many cases this is not necessary.

===Bottling and Kegging===