Whisky or 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 (maize) , rye, and wheat.Whisky is typically aged in wooden casks, generally made of charred white oak.Whisky 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. Blended malt whisky is a mixture of single malt whiskies from different distilleries. 2  If a whisky is labelled pure malt or just malt it is almost certainly a blended malt whisky. 3  This was formerly called a vatted malt whisky. 4  Blended whisky is made from a mixture of different types of whisky.