In the 1850s, the Crown imposed a tax on those distilling in Ireland through a tax on barley. Even then, malted barley was known throughout the world to make the finest whiskey, known as “pure malt” whiskey. When only malted barley is used in distillation, and made at a single distillery, you have the very definition of “single malt” whiskey. That tax, however, forever changed Irish whiskey, as almost every Irish whiskey distillery began substituting corn or other more inferior grains for barley. To this day, the biggest and most infamous Irish blended whiskeys use only corn.
Bushmills continues to distill malted barley and is the only Irish distillery time still using malted barley in all its whiskeys.