Alcohol by volume
Alcohol by volume (ABV) is the volume of pure ethanol in a beverage divided by the beverage’s total volume, expressed as a percentage.
Alcoholometry: The measurement of alcohol concentration in liquids, commonly using density or refractive properties. Alcoholometry supplies the laboratory methods used to determine a beverage’s alcohol concentration.
Standard drink: A quantity of beverage containing a defined amount of pure ethanol, with definitions varying by country. Standard drinks translate ABV and serving size into comparable amounts of ethanol.
Ethanol: The alcohol molecule consumed in alcoholic beverages, with chemical formula C₂H₆O. ABV counts ethanol, not every substance in a beverage that may be called an alcohol.
Alcohol by weight: A measure of ethanol’s mass as a percentage of a beverage’s total mass. It differs from ABV because it compares masses rather than volumes.
Hydrometer: An instrument that estimates a liquid’s density from how deeply it floats. A hydrometer can estimate alcohol content from density, especially before and after fermentation.
Ethanol metabolism: The biochemical breakdown of ethanol, chiefly in the liver, into acetaldehyde and further products. The ethanol dose estimated from ABV helps explain how beverage consumption affects the body.
Volume: The three-dimensional space occupied by a substance or object. The numerator and denominator in ABV are volumes measured under specified conditions.
Proof (alcohol): A numerical scale for alcoholic strength, with its relationship to ABV varying by country. Proof is an alternative way to state strength, not a volume fraction itself.
Distillation: A separation process that heats a liquid and condenses vapor to exploit differences in volatility. Distillation enables alcohol measurement by separating ethanol and water before analysis.
Blood alcohol content: The concentration of alcohol in a person’s blood, often expressed as mass per volume or percentage. ABV helps estimate intake, but blood alcohol content also depends on absorption and elimination.