Whiskey is a distilled alcoholic beverage made from various grains, typically rye, barley and malted barley. The process of making whiskey is called distillation, and involves boiling the fermented beer or wine to produce vapor that is then condensed into liquid again. The distillation process also separates the beverage into two fractions: one consisting largely of alcohol, the other consisting largely of water and other flavor compounds.
The use of different grains produces different styles of whiskey. The main types are rye whiskey, malt whiskey, wheat whiskey and bourbon whiskey. All the types contain some combination of water (or steam-distilled liquor), yeast, sugar or other sweetener (e.g., corn syrup), and distiller’s yeast.