Whiskey production begins with the selection of grains, typically barley, corn, rye, or wheat. These grains are mashed and mixed with water to create a mash, which is then heated to convert starches into sugars. Yeast is added to the mash, initiating fermentation, where sugars are transformed into alcohol. After fermentation, the liquid, known as wash, is distilled to increase its alcohol content. The distilled spirit is then aged in wooden barrels, usually made of oak, which imparts flavor and color. The aging process can last from a few years to several decades, resulting in the final product known as whiskey.