====Secondary Fermentation====
(To do)After primary fermentation the mostly attenuated beer is moved to a secondary fermentation vessel. Often in traditional commercial production secondary fermentation is conducted in wine barrels, however home brewers can accomplish this phase in glass or plastic carboys with low oxygen permeability. A mixed culture of Brettanomyces, Lactobacillus and Pediococcus is then introduced to the beer. If barrels are being used these "bugs" may simply come from the walls of the barrel, originating from a previous batch. Alternatively, the brewer might inoculate the wort with a mixed culture directly, either with a house culture or by introducing the dregs of sour beer. Upon their introduction these new microorganisms begin converting the longer chain sugars left over from the primary fermentation. These sugars are primarily converted into alcohol and lactic acid, increasing the degree of attenuation and lowering the pH of the beer. In the presence of oxygen acetic acid is also produced which in low amounts can be complementary, adding to the complexity of the beer.
====Aging====