Bourbon whiskey

Under 27 CFR § 5.143 every US whisky is distilled at less than 95% alcohol by volume (190 US proof), stored in oak (corn whisky excepted) and bottled at not less than 40% (80 proof). Bourbon whisky must come from a fermented mash of not less than 51% corn, be distilled at 160 proof (80% abv) or less, and be stored in charred new oak barrels at 125 proof (62.5% abv) or less. Unlike rye and the other grain whiskies in the same row of the table, bourbon may contain no colouring, flavouring or blending materials. "Straight" bourbon has spent at least two years in charred new oak.

Bourbon is a distinctive product of the United States: the word may not be used for whisky that was not distilled and aged in the United States. Nothing in the federal rule requires it to come from Kentucky.

On 4 May 1964 Congress agreed a concurrent resolution stating that bourbon whiskey is "a distinctive product of the United States" and asking federal agencies to act to prohibit imports of whisky called bourbon (see the 1964 resolution).