American whiskies are the result of a mash of cereals and water that have been saccharified by enzymes, fermented by yeast, subsequently distilled, aged and bottled. Neither bourbon nor rye may be artificially coloured.
Bourbon Whiskey Must be made from a minimum 51 % corn, distilled to a maximum of 160˚proof or 80 % abv and finally aged in new charred oak barrels at no more than 62.5 % abv. It may not be bottled below 40 % abv.
Tennessee Whiskey Must be made from a minimum of 51 % of one grain—in practice corn— and be distilled in Tennessee at less than 80 % abv. The resultant whiskey must be filtered through a bed of sugar-maple charcoal—the famous Lincoln County Process—and aged in charred oak barrels for a minimum of two years. The maple charcoal imparts a certain sweetness and smokiness, a point of difference that was legally recognised in 1941when the term Tennessee whiskey was born.
Rye Whiskey Must be made from a minimum 51 % rye and matured in new charred oak barrels ;these are rich, powerful whiskies with varying degrees of pungency.
Wheat Whiskey Must be made from a minimum 51 % wheat ; these whiskies have creamy, layered, textured characteristics.
Corn Whiskey Must be made from a minimum 80 % corn and can be aged in used or uncharred oak barrels.
Straight Whiskey Any one of the above or a combination of grains of which none is 51 % of the mash bill ; must be aged for two years in barrel.
Blended Whiskey At least 20 % of one or more of the above straight whiskies blended with unaged neutral spirit ; can be aged, blended, coloured and flavoured.