Alcohol measurement | Customary units of measurement in the United States
Alcohol proof
Alcohol proof (usually termed simply "proof" in relation to a beverage) is a measure of the content of ethanol (alcohol) in an alcoholic beverage. The term was originally used in England and was equal to about 1.8 times the percentage of alcohol by volume (ABV). The UK now uses ABV instead of proof. In the United States, alcohol proof is defined as twice the percentage of ABV. The definition of proof in terms of ABV varies from country to country. The measurement of alcohol content and the statement of content on bottles of alcoholic beverages is regulated by law in many countries. In 1972, Canada phased out the use of "proof"; in 1973, the European Union followed suit; and the UK, where the concept originated, started using ABV instead in 1980. The US code mandates the use of ABV, but permits proof to be used also. The degree symbol (°) is sometimes used to indicate alcohol proof. (Wikipedia).
