By law, bourbon must be bottled at a minimum of 80 proof, which is 40% alcohol by volume (ABV). Most bourbons fall between 80 and 100 proof. 'Bottled-in-bond' bourbon is exactly 100 proof, and barrel-strength (or cask-strength) bourbon — bottled straight from the barrel with no water added — often runs from 110 to over 130 proof.
Proof vs. ABV
In the United States, proof is simply twice the ABV. So 80 proof equals 40% alcohol, 100 proof equals 50%, and so on. The term dates back to a centuries-old test for verifying a spirit's strength, but today it's just a convenient label number.
The legal proof rules
Bourbon's strength is regulated at several points in production, not just at bottling:
- Distilled to no more than 160 proof (80% ABV).
- Entered into the barrel at no more than 125 proof.
- Bottled at no less than 80 proof (40% ABV).
Those rules are part of what legally separates bourbon from other spirits.
Common proof points
Out in the wild, you'll mostly see:
- 80–90 proof — the standard, everyday range.
- 100 proof — including 'bottled-in-bond,' a strict designation that requires 100 proof, a single distillery and season, and at least four years of aging.
- 110–130+ proof — barrel or cask strength, bottled with no water added.
Taste it straight from the barrel
Barrel-strength bourbon is a different experience — bigger, hotter, and more intense. Try it uncut at our Premium Tasting, or see all our experiences.
Keep reading: What is barrel strength bourbon? · What is straight bourbon whiskey? · What is a bourbon flight?