There is a very specific set of standards to which all bourbon makers must adhere. The Federal Standards of Identity for Distilled Spirits state that bourbon made for U.S. consumption must be:
- Produced in the United States
- Made from a grain mixture that is at least 51% corn.
- Aged in new, charred oak barrels
- Distilled to no more than 160 (U.S.) proof (80% alcohol by volume)
- Entered into the container for aging at no more than 125 proof (62.5% alcohol by volume)
- Bottled at 80 proof or more (40% alcohol by volume)