What is Proof?
What is Proof?
Alcohol proof is a measure of the content of ethanol (alcohol) in an alcoholic drink. The term was originally used in the UK and was equal to about 1.75 times the ABV. In the US, alcohol proof is defined as twice the percentage of ABV.
The term Proof dates from 16th century England, where spirits were taxed at different rates depending on their alcohol content. Spirits were tested by soaking a pellet of gunpowder in them. If the gunpowder could burn, the spirit was rated ‘above proof’ and taxed at a higher rate. As gunpowder would not burn if soaked in rum that contained less than 57.15% ABV, rum that contained this percentage of alcohol was defined as having 100 degrees proof. The gunpowder test was replaced by a specific-gravity test in 1816
From the 18th century until 1 January 1980, the UK measured alcohol content by proof spirit, defined as spirit a gravity of 12⁄13 that of water, or 923 kg/m3, and equivalent to 57.15% ABV.
The proof system in the United States was established around 1848 and was based on percent alcohol. 50% alcohol by volume was defined as 100 proof.