How bourbon is made

Bourbon barrels can be used only once for bourbon, so the industry exports its leftover barrels around the world.

stations: 6
things upstream: 43
raw sources: 19
steps from the ground: 6

The short version

Bourbon is a whiskey made from a grain mix of at least 51 percent corn, fermented with yeast, distilled and aged in new charred oak containers. The clear spirit, called white dog, takes its color and vanilla flavor from the charred wood. It is diluted and bottled at no less than 40 percent alcohol.

Grind and mix the mash

The grain, at least 51 percent corn with the rest any cereal grain, is ground and mixed with water. Mash from a previous distillation is often added to make a sour mash and keep batches consistent.

Goes in
Corn Barley Water
Ferment with yeast

Yeast is added and the mash ferments. The sour mash also controls the growth of bacteria that could taint the whiskey.

Goes in
Baker's yeast
Distill twice

Most modern bourbon is first run through a column still, then redistilled in a doubler, which is basically a pot still. The spirit comes off at typically between 65 and 80 percent alcohol.
Fill charred barrels

The clear white dog is put into new charred oak containers, almost always American white oak barrels, at no more than 62.5 percent alcohol.

Goes in
Oak wine barrel
Age in the wood

Caramelized sugars and vanillins in the charred wood give the spirit color and much of its flavor. Straight bourbon must age at least two years, and the longer it stays the more color it gains.

at least 2 years for straight bourbon
Filter, dilute, bottle

After maturing, the whiskey is typically filtered, diluted with water and bottled at no less than 80 US proof, which is 40 percent alcohol.

Goes in
Glass bottle Water

End of the lineBourbon

Worth repeating

Congress recognized bourbon in 1964 as a distinctive product of the United States.
Barrels cannot be reused for bourbon, so most are sold to distillers in Canada, Scotland, Ireland, Mexico and the Caribbean.
Emptied barrels remain saturated with 2 to 3 U.S. gallons of bourbon.