Whiskey is a type of distilled alcoholic beverage made from fermented grain mash. Various grains (which may be malted) are used for different varieties, including barley, corn, rye, and wheat. Whiskey is typically aged in wooden casks, which are typically made of charred white oak. Uncharred white oak casks previously used for the aging of sherry are also sometimes used.
Whiskey is a strictly regulated spirit worldwide with many classes and types. The typical unifying characteristics of the different classes and types are the fermentation of grains, distillation, and aging in wooden barrels.