Why Is Proof Double The Percent?
Proof is double the percent because it is a measurement used to indicate the alcohol content in liquor. It represents the percentage of alcohol multiplied by two. For example, if a liquor has 40% alcohol by volume, its proof would be 80. This system of measurement originated in England where they determined that the amount of alcohol in a liquor could be determined by mixing it with gunpowder and testing if it would ignite. If the liquor would ignite, it was considered to be “proof” of its alcohol content.