The American whiskey category can be broken down into several subcategories. They are differentiated by the proof at which they are distilled, the types of grain in the mash, and the length of time they are aged. Popular American whiskies include bourbon whiskey, Tennessee whiskey, and blended American whiskey. Most North American whiskies are made in column stills and aged in oak barrels, which can be charred or not charred.
For a whiskey to be considered an American whiskey, it must meet the following criteria as set forth by the United States government:
• Be made from a grain mash
• Be distilled at 90 percent ABV or less
• Be reduced to no more than 62.5 percent ABV (125 proof) before being aged in oak barrels (exceptfor corn whiskey, which does not have to be aged in wood)
• Have the aroma, taste, and characteristics attributed to whiskey
• Be bottled at no less than 40 percent ABV (80 proof)
Bourbon whiskey must contain a minimum of 51 percent corn, be produced in the U.S., and be distilled at less than 80 percent ABV. It must also be aged for a minimum of two years in new charred oak barrels.
Tennessee whiskey must contain a minimum of 51 percent corn, be produced in Tennessee, and be distilled at less than 80 percent ABV. It must also be filtered through a bed of sugar maple charcoal and be aged for a minimum of two years in new charred barrels.
Blended American whiskey is required to contain at least 20 percent straight whiskey. The balance must be an unaged neutral spirit, or in some cases, a high-proof light whiskey. Blended whiskies have a whiskey flavor profile similar to bourbon, but lack the defining taste characteristics of a straight whiskey.
For a whiskey to be designated as a rye whiskey, it not only has to have at least 51 percent rye grain, but it must also be distilled at less than 80 percent ABV (160 proof) and be aged for a minimum of two years in new charred oak barrels.
While there is a small amount of rye whiskey that is bottled and marketed, most of the production of rye is blended into other whiskies to give them additional structure and character.
— Sara Kay, The Spir.it