Different brands and types of beer typically contain 3 to 10 percent alcohol by volume, or ABV. Pilsner, for example, has 3 to 6 percent ABV, and Stout has 5 to 10 percent ABV.
ABV is the standard unit for measuring the alcohol or ethanol content in a given volume of alcoholic beverage. Alcohol content is also measured in proof, which is double the ABV value, and alcohol by weight.
In making beer, ethanol is produced when yeast consumes the sugar in the beer solution during fermentation. To measure ABV, the specific gravity of the solution is measured using a hydrometer before and after fermentation. Then, the measured values are used to calculate ABV using the formula 131 x (starting SG - final SG), with SG standing for "specific gravity."