“Proof” is a number used to indicate the alcohol content of distilled spirits. This archaic term is derived from the concentration of alcohol necessary for combustion of gunpowder when mixed with the liquor. The minimum amount of alcohol required for the mixture to burn was 50 percent, which was 100 proof. Most liquors are 80 to 90 proof — 40 percent to 45 percent alcohol — but many varieties are 100 proof or more.


Whiskeys

Most bourbons, scotches and other varieties of whiskey are either 80 or 86 proof, but several distilleries also produce whiskeys with higher alcohol content. For instance, Old Grand Dad offers a 100 proof version along with its standard 86 proof blended whiskey, and Wild Turkey has a 101 proof bourbon as well as a rye whiskey with the same alcohol content.

Vodka and Rum

Big-name makers of vodka also offer versions with a higher alcohol content. Stolichnaya and Smirnoff each sell 100 proof vodkas, along with their standard 80 proof varieties. Captain Morgan, maker of a popular spiced rum, also sells it in a 100 proof.

Liqueurs

Several sweet liqueurs have high alcohol content, and 100 proof is the most popular. These high-powered after-dinner drinks include cinnamon and peppermint schnapps products. The fruit-flavored bourbon Southern Comfort also comes in a 100 proof version.

Absinthe

Absinthe is an anise-flavored herbal drink that is not usually available in the United States because of its supposed hallucinogenic effects. Some brands are made without the banned herbs, and these are sold in the United States. Absinthe comes in a wide variety, and at least one is 100 proof: Absinthe Fee Verte Classic.

Higher Proofs

Several whiskeys have alcohol content of substantially more than 100 proof. Macallan makes a scotch it calls cask strength at is 116 proof; George T. Stagg bourbon is 136 proof, or 68 percent alcohol. Some absinthes contain as much as 75 percent alcohol, making them 150 proof, and Bacardi and other distillers produce 151 proof dark rums. Some liquor stores carry a pure grain alcohol, Everclear. It has an alcohol concentration of 95 percent, or 190 proof, the most achievable using a still.