Have you noticed the label on the bottle of your alcoholic beverage? Ever wondered what alcohol proof means and why it differs from ABV (alcohol by percentage) though both indicate a particular liquor’s potency? Let’s try to find some answers.
Alcohol proof vs. ABV
For an alcoholic beverage, alcohol proof refers to the content of ethanol (a particular type of alcohol) in it. On the other hand, ABV as the name suggests is the alcohol percentage in the overall liquid. You can trace the origin of the term “alcohol proof” back to the 18th century United Kingdom. In 1816, England set the threshold of “proof” at 57.06 percent ABV. In 1952, this measure was standardized where a 100-proof spirit was almost 57 percent ABV and the proof to ABV ratio was 4:7. This means to calculate the alcohol proof, you would need to multiply the ABV by 1.75. It was around 1980 when the U.K. started to adopt a simpler ABV scale for labelling spirits.
Americans had a different approach for measuring liquor’s potency, once the alcohol industry came to the U.S. They used a simple measurement system where alcohol proof was two times the ABV. Thus, liquor with 30% ABV would have 60 alcohol proof. But to be labelled a “proof spirit,” a beverage had to be at least 100 proof. This measurement system is still valid in the U.S, though 40 proof is now the lowest end.
Perhaps France’s measurement system was the simplest. Developed in 1824 by Joseph-Louis Gay-Lussac – a French scientist, the system considered 100% ABV equal to 100 proof while 100% water by volume was 0 proof. This means that alcohol proof was the same as the ABV percentage. Now called the OIML scale (which stands for Organization Internationale de Metrologies’ Légale), it indicates a 1:1 ratio between ABV and alcohol proof.
If you were to compare the three proof scales in their earlier days, you’d have noticed that any liquor with 45% ABV would be 45 and 90 alcohol proof in France and the U.S. respectively. However, in the United Kingdom, it would be about 78.9 alcohol proof.
Low Alcohol proof vs. high alcohol proof
Mostly, the term “alcohol proof” is used for liquors with the potency of 40 proof and above. 40 alcohol proof is the lowest end of ABV that would be applicable for low-alcohol beverages like gin, brandy and so on.
You won’t find “alcohol proof” mentioned on a bottle of beer or wine. While the average alcohol content in beer is about 5 percent ABV, it’s about 12 percent for wine. This means technically, you can still say beer to be 10 proof and wine 24 proof. But since such labelling is unnecessary, you won’t find them displayed on your bottle of liquor.
Flavoured liquors like flavoured rum Malibu (42 proof) and flavoured whiskey Fireball (66 proof) are among liquors with the lowest alcohol proof. At the other end of the spectrum are their full-bodied peers like Golden Grain (190 proof), Ever clear (190 proof), and Spirytus (192 proof).