Classic Mixology: Cocktail & Mixed Drink Recipes

yeast

What it is:  Additive

Alcoholic beverages are defined as beverages that contain ethanol (C2H5OH). This ethanol is almost always produced by fermentation - the metabolism of carbohydrates by certain species of yeast under anaerobic or low-oxygen conditions. Beverages such as wine, beer, or distilled spirits all use yeast at some stage of their production.

Further reading:  http://en.wikipedia.org/wiki/Yeast