Malt Whiskey is made from malted barley. In the United States, the mash bill (grain recipe) of malt whisky must be comprised of a minimum of 51% malted barley. Although Malt Whiskey can be made with other malted grains instead of barley, those iterations are not referred to as Malt Whiskey without specification of which grain has been substituted in its place. There are different definitions and restrictions governing the production of Malt Whiskey depending on where in the world it is made.