Bourbon is a distinct product of the United States of America, as declared by Congressional Resolution in 1964.
Bourbon must be aged in a new, charred oak container. This container is almost always a barrel.
The grain recipe—or mash bill—used to make Bourbon must contain at least 51% corn.
Bourbon cannot be distilled above 160 proof. This preserves flavors and character from the cooking and fermentation process.
Bourbon cannot enter the barrel at more than 125 proof. Water is added to achieve the desired entry proof.
When Bourbon is bottled, like all whiskey, the bottles cannot be filled at less than 80 proof.
It must be genuine—no color or flavoring agents or other spirits may be added.