What alcohol has the least amount of alcohol?

The alcohol beverage with the fewest calories per serving is liquor (distilled spirits).

Beck's Light has 2.3% alcohol and 64 caloriesBud Select 55 only has 2.4% alcohol and 55 calories

Several internet resources list Bourbon (60-65 calories per oz.) and Vodka (60 calories per oz.) as the two liquors with the lowest calories. Vodka and Bourbon.

A standard drink, in the US, contains 0.6 ounces of pure alcohol.

The amount of alcohol in a drink is generally measured in proof, where 200 proof is 100% alcohol. Typically, hard liquor is 80 or 86 proof, wine is 21 proof, and beer is 11 proof.