Whisky is made from grains that have fermented. According to Jewish tradition, wheat, barley, rye and spent, oats and spelt are the “five grains,” which can become chametz when brought into contact with water. On Passover, it is forbidden to eat or even own chametz.

For this reason whiskey (including scotch and bourbon) is essentially not kosher for Passover.

Learn more: Is There Kosher for Passover Alcohol?