Changes

Some brewers have good success reusing a yeast cake or a portion of a yeast cake by leaving the wort in contact with the old yeast cake for 1-4 days. After 1-4 days, a fresh culture of ''Saccharomyces'' is pitched to finish the fermentation. The 1-4 day head start gives the souring bacteria a head start and results in a low pH beer. The harvested yeast cake can also be pitched at the same time as a fresh culture of Saccharomyces, or afterward. The decided timing on when to pitch the harvest sour yeast cake will effect affect the acidity of the sour beer: early pitching of the sour yeast cake generally produces a more acidic beer, and later pitching generally produces a less acidic beer.

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.