Alcohol measurements

Alcohol measurements are units of measurement for determining amounts of beverage alcohol. Alcohol concentration in beverages is commonly expressed as alcohol by volume (ABV), ranging from less than 0.1% in fruit juices to up to 98% in rare cases of spirits. A "standard drink" is used globally to quantify alcohol intake, though its definition varies widely by country. Serving sizes of alcoholic beverages also vary by country.
The concentration of alcohol in a beverage is usually stated as the percentage of alcohol by volume (ABV, the number of milliliters (ml) of pure ethanol in 100 ml of beverage) or as proof. In the United States, proof is twice the percentage of alcohol by volume at 60 degrees Fahrenheit (e.g. 80 proof = 40% ABV). Degrees proof were formerly used in the United Kingdom, where 100 degrees proof was equivalent to 57.1% ABV. Historically, this was the most dilute spirit that would sustain the combustion of gunpowder.
Ordinary distillation cannot produce alcohol of more than 95.6% by weight, which is about 97.2% ABV (194.4 proof) because at that point alcohol is an azeotrope with water. A spirit which contains a very high level of alcohol and does not contain any added flavoring is commonly called a neutral spirit. Generally, any distilled alcoholic beverage of 170 US proof or higher is considered to be a neutral spirit.
Most yeasts cannot reproduce when the concentration of alcohol is higher than about 18%, so that is the practical limit for the strength of fermented drinks such as wine, beer, and sake. However, some strains of yeast have been developed that can reproduce in solutions of up to 25% ABV.
A standard drink is a notional drink that contains a specified amount of pure alcohol. The standard drink is used in many countries to quantify alcohol intake. It is usually expressed as a measure of beer, wine, or spirits. One standard drink always contains the same amount of alcohol regardless of serving size or the type of alcoholic beverage. The standard drink varies significantly from country to country. For example, it is 7.62 ml (6 grams) of alcohol in Austria, but in Japan it is 25 ml (19.75 grams):
A standard drink of 10g alcohol is used in the WHO AUDIT (Alcohol Use Disorders Identification Test)'s questionnaire form example, and has been adopted by more countries than any other amount. 10 grams is equivalent to 12.7 millilitres.
The following table lists common sizes for liquors and spirits.
Shot sizes vary significantly from country to country. In the United Kingdom, serving size in licensed premises is regulated under the Weights and Measures Act (1985). A single serving size of spirits (gin, whisky, rum, and vodka) are sold in 25 ml or 35 ml quantities or multiples thereof. Beer is typically served in pints (568 ml), but is also served in half-pints or third-pints. In Israel, a single serving size of spirits is about twice as much, 50 or 60 mL.
The shape of a glass can have a significant effect on how much one pours. A Cornell University study of students and bartenders' pouring showed both groups pour more into short, wide glasses than into tall, slender glasses. Aiming to pour one shot of alcohol (1.5 ounces or 44.3 ml), students on average poured 45.5 ml & 59.6 ml (30% more) respectively into the tall and short glasses. The bartenders scored similarly, on average pouring 20.5% more into the short glasses. More experienced bartenders were more accurate, pouring 10.3% less alcohol than less experienced bartenders. Practice reduced the tendency of both groups to over pour for tall, slender glasses but not for short, wide glasses. These misperceptions are attributed to two perceptual biases:
The British Reputed Pint and Reputed Quart were used in Great Britain and throughout the Empire from the late 17th century until the early 20th century. Originally there were different standard gallons depending on the type of alcohol. That meant that the Reputed measures varied depending on which standard gallon was used. A Reputed Pint of beer was equal to 285 mL (1/2 an Ale Pint, or equivalent to 10 imperial oz. or 9.63 US oz.) and a Reputed Quart of wine was equal to 730 mL (3/4 of a Wine Quart, or equivalent to 25.69 Imp. oz. or 24.68 US fluid oz.). When the Imperial system was adopted in 1824, the fluid gallon was standardized on the old Ale Gallon (which had 160 fluid ounces). However, Reputed pints and quarts were still used by breweries and merchants, but measurements were now based on the Imperial system. There was still confusion about whether Reputed or Imperial measures was being used by the merchant, so eventually Imperial pints and quarts were made standard in the early 20th century.
The United States adopted the British Wine Gallon (which had 128 fluid ounces) as standard. The laws concerning the production and sale of alcohol stated that it had to be sold in portions of a gallon for tax purposes. A standard case of bottled beer, wine or liquor had to be equal to two gallons and bottles came in half-dozens and dozens rather than fourths (quarts) and eighths (pints). There would be 24 small bottles (Twelfths of a US gallon) or 12 large bottles (Sixths of a US gallon) per case. The bottles were later increased in size (Tenths and Fifths of a US gallon) to be equivalent to British Reputed Pints and Quarts, allowing them to be interchangeable for export. The American liquor industry later referred to these measures as "Commercial Pints" (Tenths) and "Commercial Quarts" (Fifths).
The following table contains various measurements that are commonly applied to wine.
The 750 mL Standard wine bottle was chosen because it was the standard French wine bottle once moulded glass bottles were available in the 19th century. Previously there was a roughly 730 mL limit to glass-blown bottles because that was the limit of a glassblower's lungs. The volume was rounded up to 750 mL and then was used as the base size for French wine containers, with all subdivisions and multiples figured from it. The rest of the world followed suit with equivalent customary measurement versions of their own (like the British Reputed Quart).
Following metrication in 1980, American still wines can also be sold in large multi-liter containers, but only in full liters. They are typically sold in glass demijohns or foil bag-in-box containers holding 4, 5, 7, 8, or 10 Liters.