Alcohol By Volume

It is defined as the number of millilitres (mL) of pure ethanol present in 100 mL (3.5 imp fl oz; 3.4 US fl oz) of solution at 20 °C (68 °F). The number of millilitres of pure ethanol is the mass of the ethanol divided by its density at 20 °C (68 °F), which is 0.78945 g/mL (0.82353 oz/US fl oz; 0.79122 oz/imp fl oz; 0.45633 oz/cu in). The alc/vol standard is used worldwide. The International Organization of Legal Metrology has tables of density of water–ethanol mixtures at different concentrations and temperatures.

In some countries, e.g. France, alcohol by volume is often referred to as degrees Gay-Lussac (after the French chemist Joseph Louis Gay-Lussac), although there is a slight difference since the Gay-Lussac convention uses the International Standard Atmosphere value for temperature, 15 °C (59 °F).

Volume change

Mixing two solutions of alcohol of different strengths usually causes a change in volume. Mixing pure water with a solution less than 24% by mass causes a slight increase in total volume, whereas the mixing of two solutions above 24% causes a decrease in volume. The phenomenon of volume changes due to mixing dissimilar solutions is called "partial molar volume". Water and ethanol are both polar solvents. When water is added to ethanol, the smaller water molecules are attracted to the ethanol's hydroxyl group, and each molecule alters the polarity field of the other. The attraction allows closer spacing between molecules than is usually found in non-polar mixtures.

Thus, alc/vol is not the same as volume fraction expressed as a percentage. Volume fraction, which is widely used in chemistry (commonly denoted as v/v), is defined as the volume of a particular component divided by the sum of all components in the mixture when they are measured separately. For example, to make 100 mL of 50% alc/vol ethanol solution, water would be added to 50 mL of ethanol to make up exactly 100 mL. Whereas to make a 50% v/v ethanol solution, 50 mL of ethanol and 50 mL of water could be mixed but the resulting volume of solution will measure less than 100 mL due to the change of volume on mixing, and will contain a higher concentration of ethanol. The difference is not large, with the maximum difference being less than 2.5%, and less than 0.5% difference for concentrations under 20%.

Threshold levels

Legal thresholds

Some drinks have requirements of alcoholic content in order to be certified as a certain alcohol brand or label. Some alcoholic drinks may be considered legally as non-alcoholic in spite of having relatively high alcohol levels such as in Finland where products under 3 degrees can be sold legally as alcohol-free.

Low-alcohol beers (0.5<) are considered in some countries such as Iran as permitted (or "halal" under Muslim vocabulary) despite alcohol being banned. However, the level of alcohol-free beers is typically the lowest commercially sold 0.05.

Biological thresholds

It is near impossible for a healthy person to become intoxicated drinking low-alcohol drinks. The low concentration severely limits the rate of intake, which is easily dispatched by human metabolism. Quickly drinking 1.5 L of 0.4% alc/vol beer in an hour resulted in a maximum of 0.0056% BAC in a study of German volunteers. Healthy human kidneys can only excrete 0.8–1.0 L of water per hour, making water intoxication likely to set in before any alcoholic intoxication.

The process of ethanol fermentation will slow down and eventually come to a halt as the alcohol produced becomes too concentrated for the yeast to tolerate, defining an upper limit of alc/vol for non-distilled alcoholic drinks. The typical tolerance for beer yeasts is at 8–12%, while wine yeasts typically range from 14–18%, with speciality ones reaching 20% alc/vol. Any higher would require distillation, producing liquor.

Typical levels

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

Drink	Typical alc/vol	Lowest	Highest
Fruit juice (naturally occurring)	0–0.11% They qualify as alcohol-free drinks in most countries. (most juices do not have alcohol but orange or grape [the highest here] may have some from early fermentation)	0.00	0.11
Low-alcohol beer	0.05–1.2% (usually not considered as alcohol legally) Under 2.5% in Finland, and 2.25% in Sweden, however.	0.05	1.02
Kvass	0.05–1.5%	0.05	1.50
Kefir	0.2–2.0%	0.20	2.00
Sobia	0.2–6.8%	0.20	6.80
Kombucha	0.5–1.5%	0.50	1.50
Kumis	0.7–4.5% (usually 0.7–2.5%)	0.70	4.50
Boza	1.0%	1.00	1.00
Chicha	1.0–11% (usually 1–6%)	1.00	11.00
Tubâ	2.0–4.0%	2.00	4.00
Chūhai	3.0–12.0% (usually 3–8%)	3.00	12.00
Pulque	2.0–7.0% (usually 4–6%)	2.00	12.00
Beer	(usually 4–6%)	2.00	10.00
Cider	(usually 4–8%)	4.00	8.00
Palm wine	4.0–6.0%	4.00	6.00
Alcopops	4.0–17.5%	4.00	17.50
Malt liquor	5.0%	5.00	5.00
Hard seltzer	5.0%	5.00	5.00
Four Loko	6–14%	6.00	14.00
Makgeolli	6.5–7%	6.50	7.00
Kuchikamizake	7%	7.00	7.00
Barley wine (strong ale)	8–15%	8.00	15.00
Mead	8–16%	8.00	16.00
Wine	5.5–16% (most often 12.5–14.5%)	5.50	16.00
Bahalina	10–13%	10.50	13.00
Basi	10–16%	10.00	16.00
Bignay wine	12–13%	12.00	13.00
Duhat wine	12–13%	12.00	13.00
Tapuy	14–19%	14.00	19.00
Kilju	15–17%	15.00	17.00
Dessert wine	14–25%	14.00	25.00
Sake	15% (or 18–20% if not diluted prior to bottling)	15.00	20.00
Liqueurs	15–55%	15.50	55.00
Fortified wine	15.5–20% (in the European Union, 15–22%)	15.50	22.00
Soju	14–45% (usually 17%)	14.00	45.00
Rice wine	18–25%	18.00	25.00
Shochu	25–45% (usually 25%)	25.00	45.00
Awamori	25–60% (usually 30%)	25.00	60.00
Rượu đế	27–45% (usually 35% – except Ruou tam – 40–45%)	27.00	45.00
Bitters	28–45%	28.00	45.00
Applejack	30–40%	30.00	40.00
Pisco	30–48%	30.00	48.00
Țuică (Romanian drink)	30–65% (usually 35–55%)	30.00	65.00
Mezcal, Tequila	32–60% (usually 40%)	32.00	60.00
Vodka	35–95% (usually 40%, minimum of 37.5% in the European Union)	35.00	95.00
Rum	37.5–80% (usually 40%)	37.50	80.00
Brandy	35–60% (usually 40%)	35.00	60.00
Grappa	37.5–60%	37.50	60.00
Ouzo	37.5%	37.50	37.50
Gin	37.5–50%	37.50	50.00
Pálinka	37.5–86% (usually 52%)	37.50	86.00
Cachaça	38–48%	38.00	48.00
Sotol	38–60%	38.00	60.00
Stroh	38–80%	38.00	80.00
Fernet	39–45%	39.00	45.00
Lambanog	40–45%	40.00	45.00
Nalewka	40–45%	40.00	45.00
Tsipouro	40–45%	40.00	45.00
Rakı	40–50%	40.00	50.00
Scotch whisky	40–63.5%	40.00	63.50
Whisky	40–68% (usually 40%, 43% or 46%)	40.00	68.00
Baijiu	40–65%	40.00	65.00
Chacha	40–70%	40.00	70.00
Bourbon whiskey	min 40% bottled, 43%, 50%, max 62.5% bottled, max 80% distilled	40.00	80.00
Rakija (Central/Southeast European drink)	40–86%	42.00	86.00
Maotai	43–53%	43.00	53.00
Absinthe	45–89.9%	45.00	89.90
Arak	60–65%	60.00	65.00
Oghi	60–75%	60.00	75.00
Poitín	60–95%	60.00	95.00
Centerbe (herb liqueur)	70%	70.00	70.00
Neutral grain spirit	85–95%	85.00	95.00
Cocoroco	93–96% ^{[citation needed]}	93.00	96.00
Rectified spirit	95% up to a practical limit of 97.2%	95.00	97.20

Practical estimation of alcohol content

During the production of wine and beer, yeast is added to a sugary solution. During fermentation, the yeasts 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 estimated. There are a number of empirical formulae which brewers and winemakers use to estimate the alcohol content of the liquor made.

Specific gravity is the density of a liquid relative to that of water, i.e., if the density of the liquid is 1.05 times that of water, it has a specific gravity of 1.05. In UK brewing usage, it is customary to regard the reference value for water to be 1000, so the specific gravity of the same example beer would be quoted as 1050. The formulas here assume that the former definition is used for specific gravity.