Bourbon! That most American of spirits. Despite legend, bourbon need not hail from Bourbon County, Kentucky (although most of it does.) However, there are strict rules to differentiate bourbon from other whiskies and even other American sour mashes.
The key attributes of bourbon follow.
- Produced in the United States.
- Produced from a grain mash that is at least 51% corn. (The remainder of the mash can be made of wheat, rye, or malted barley.)
- Aged in charred oak containers barrels.
- Distilled to no more than 160 (U.S.) proof (80% a.b.v.)
- Barrel aging begun at no more than 125 proof (62.5 a.b.v.)
- Bottled at 80 proof or more (40% a.b.v.)
To make bourbon, distillers first create a mash from ground grains (in a accordance with law) and distilled water. Sometimes, an older mash is added to guarantee consistent pH levels. Then, yeast is added and fermentation begins. The whole mixture is put into a still and a clear liquor is produced. Then, the product is loaded into new, charred oak barrels for aging. During this process, bourbon picks up it’s distinctive brown hue and an added flavor from the barrels. Finally, the juice is removed from the barrels, filtered, diluted with water to create a consistent a.b.v., and then bottled.
(Fun fact: The barrels can not be reused to make more bourbon by law.)