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Once the wort is produced and chilled, the mixed culture can be pitched as normal. If using a mixed culture from a commercial yeast lab, it is usually recommended to not make a yeast starter with it because the starter will throw off the intended ratios of the microbes. Instead of buying a single mixed culture, a brewer can create their own mixed culture by combining their own ratios from single cultures of yeast and bacteria. A single mixed culture can be supplemented by adding pure cultures from different yeast labs as well. Another suggestion that often helps produce a higher quality sour beer is to supplement the mixed culture with a [[Commercial Sour Beer Inoculation]]. In general, the more diversity of microbes, the more complex a sour beer can potentially be. Using a [[Sour Worting]] method in conjunction with this method can help increase acidity that may not otherwise be produced by some commercial blends (Wyeast Roeselare is known for this characteristic, for example).
Aging is generally required for mixed fermentations that include Brettanomyces. Expect an aging time of at least 9 months, but preferably 12-18 months or longer. For sour beers that only use Lactobacillus and Saccharomyces, sometimes also known as [[Quick Sours]], aging is optional. Sour beer should be aged in an environment that minimizes high temperatures and exposure to oxygen. Drastic temperature fluctuations and changes in atmospheric pressure will cause a vacuum inside of the fermentation vessel causing water airlocks to "suck back" air into the fermenter. This could potentially contribute to acetic acid and ethyl acetate (nail polish aroma in high concentrations) production by Brettanomyces, however the development of a pellicle can help protect against this. Filling the carboy to the neck will also help minimize the surface area of the beer that can be exposed to air. Avoid over sampling the beer (once every 3 months at the very most). It should also be noted that micro-oxygenation is helpful for creating certain flavors in sour beer, and many homebrewers have reported not having any issues with over exposure to oxygen using water-based airlocks.
==Three Stage Fermentation==