Proof
Also known as: alcohol proof
A measurement of alcohol content primarily used in the United States, where proof equals twice the ABV percentage.
Proof is a measurement of alcohol content primarily used in the United States, where it equals twice the alcohol by volume (ABV) percentage. Understanding proof helps when selecting spirits and following cocktail recipes. The proof system has historical origins in 18th century Britain. To verify alcohol content, officials would soak a pellet of gunpowder in the spirit and attempt to ignite it. If it burned, the spirit was proven to have sufficient alcohol - about 57% ABV. This was deemed 100 proof under the British system. The American proof system is simpler: proof equals ABV multiplied by two. An 80 proof spirit contains 40% alcohol. A 100 proof spirit is 50% alcohol. To convert proof to ABV, simply divide by two. This straightforward relationship makes calculations easy once you know the formula. Standard spirits in the United States are typically bottled at 80 proof (40% ABV). This includes most vodka, gin, rum, tequila, and blended whiskey. However, many spirits deviate from this standard. Bourbon must be bottled at minimum 80 proof by law, but many premium bourbons are bottled at higher proofs - 90, 100, or even barrel strength at 120+ proof. Bottled in Bond bourbon is always exactly 100 proof, a designation from an 1897 law guaranteeing quality. Overproof spirits exceed the standard 80 proof. Navy strength gin is 114 proof (57% ABV), matching the historical British standard. Overproof rum can reach 151 proof (75.5% ABV). These spirits require careful handling and recipe adjustment. When following cocktail recipes, pay attention to proof. A recipe calling for 2 oz of rum assumes standard 80 proof. Using 151 proof rum without adjustment creates a dramatically different (and much stronger) drink. Scale down the spirit or adjust other ingredients accordingly. Cask strength or barrel proof whiskeys are bottled directly from the barrel without dilution, often ranging from 110-140 proof. These offer intense flavor but may benefit from a few drops of water to open up and reduce alcohol burn. The UK abandoned its original proof system in 1980, adopting ABV as the standard measurement. Most of the world now uses ABV exclusively. The American proof system persists primarily due to tradition and legal requirements for labeling.
💡 Pro Tips
- Divide US proof by 2 to get ABV percentage
- Adjust recipes when using higher or lower proof spirits
- 100 proof equals exactly 50% alcohol
- Bottled in Bond always means 100 proof bourbon
⚠️ Common Mistakes to Avoid
- Forgetting to adjust recipes for high-proof spirits
- Confusing US proof with the old UK system
- Assuming proof and ABV are interchangeable terms
- Not accounting for proof when calculating drink strength
