A single serving of an alcoholic beverage varies from one and a half ounces to 12 ounces because of the variation in the concentration of alcohol in each type of beverage.
One serving of: regular beer is 12 ounces, malt liquor is 8 to 9 ounces, table wine is 5 ounces, fortified wine, such as sherry or port, is 3 or 4 ounces, cordial, liqueur or apertif is 2 or 3 ounces and 80-proof spirits or brandy are 1.5 ounces.
The concentration of alcohol in these beverages is: 5 percent in beer, 7 percent in malt liquor, 12 percent in wine, 17 percent in fortified wine, 24 percent in cordials and 40 percent in brandy or 80-proof spirits.
The amount of alcohol in each type of beverage is printed on the label. Some varieties, such as light beer, or imported spirits, may have a different concentration of alcohol than is standard. Mixed drinks may also contain more than one serving of alcohol if several different shots are added to one glass.