Bourbon whiskey is primarily made from corn. By U.S. law, bourbon must have a mash bill containing at least 51% corn, with the remainder typically made up of other grains such as rye, barley, or wheat. This corn content is what distinguishes bourbon from other types of whiskey
. In addition to the grain requirements, bourbon must be aged in new, charred oak barrels and distilled and bottled in the United States. While Kentucky is strongly associated with bourbon production, bourbon can legally be made anywhere in the U.S.
. In summary, the defining ingredient of bourbon whiskey is corn, which must constitute at least 51% of the grain mixture used in its production.
