The alcohol by volume shown on a bottle of absinthe.

Alcohol by volume (abbreviated as abv, ABV, or alc/vol) is a standard measure of how much alcohol (ethanol) is contained in an alcoholic beverage (expressed as a percentage of total volume).^[1][2][3] The ABV standard is used worldwide.

In some countries, alcohol by volume is referred to as degrees Gay-Lussac (after the French chemist Joseph Louis Gay-Lussac).^[4]

Typical levels[link]

Details about typical amounts of alcohol contained in various beverages can be found in the articles about individual drinks.

Alcohol proof[link]

Another way of specifying the amount of alcohol is alcohol proof, which in the United States is twice the alcohol-by-volume number,^[7][8] while in the United Kingdom it was 1.75 times the number (expressed as a percentage). For example, 40% abv is 80 proof in the US and 70 proof in the UK. However, since 1980, alcoholic proof in the UK has been replaced by abv as a measure of alcohol content.

Proof and alcohol by weight[link]

In the United States, a few states regulate and tax alcoholic beverages according to alcohol by weight (abw), expressed as a percentage of total mass. Some brewers print the abw (rather than the abv) on beer containers, particularly on low-point versions of popular domestic beer brands.

At relatively low abv, the alcohol percentage by weight is about 4/5 of the abv (e.g., 3.2% abw is equivalent to 4.0% abv).^[9] However, because of the miscibility of alcohol and water, the conversion factor is not constant but rather depends upon the concentration of alcohol. 100% abw, of course, is equivalent to 100% abv.

Calculation of alcohol content[link]

During the production of wine and beer, yeast is added to a sugary solution. During fermentation, the yeast organisms consume the sugars and produce alcohol. The density of sugar in water is greater than the density of alcohol in water. A hydrometer is used to measure the change in specific gravity (SG) of the solution before and after fermentation. The volume of alcohol in the solution can then be calculated.

Wine[link]

The simplest method for wine has been described by English author C.J.J. Berry:^[10]

• Failed to parse (Missing texvc executable; please see math/README to configure.): ABV = (Starting SG - Final SG)/7.36

Beer[link]

The calculation for beer is:

Where 1.05 is number of grams of ethanol produced for every gram of CO₂ produced and .79 is the density of ethanol,

• ABV = ((1.05 * (Starting SG – Final SG)) / Final SG) / 0.79 * 100 ^[11]

However, many brewers use the following formula:

• ABV = (Starting SG - Final SG) * 131

See also[link]

• Alcohol proof
• Unit of alcohol
• Apparent molar property

References[link]

Bibliography[link]

• Hehner, Otto (1880). Alcohol Tables: giving for all specific gravities, from 1.0000 to 0.7938, the percentages of absolute alcohol, by weight and volume. London: J & A Churchill, ASIN B0008B5HOU. 

External links[link]

• How do brewers measure the alcohol in beer? HowStuffWorks