At that time cash was very scarce on the frontier. Spirits were often used in lieu of cash. The distillers of this area would have paid the tax in spirits, but the Federal Gov’t. demanded (non-existant) cash.
Also, as the biggest distiller of spirits in those then United States, Washington had a vested interest in keeping down the competition.
It was the easiest way to haul corn to market and turn it into cash.