What ABV means

Alcohol by volume is a ratio of volumes: millilitres of pure ethanol per 100 millilitres of finished drink. It is not a measure of mass, and because ethanol is less dense than water — about 0.789 grams per millilitre — the mass of alcohol in a drink is smaller than the volume figure suggests. A litre of 5 per cent cider contains 50 ml of ethanol, which weighs about 39 grams.

That conversion matters because health guidance is framed in grams. A UK unit is 10 ml, or about 8 grams, of pure ethanol; a US standard drink is about 14 grams. Both are derived from the ABV and the volume, and neither can be worked out without both numbers.

ABV on a label is subject to a permitted tolerance, and for cider that tolerance is larger than most people expect. Annex XII of Regulation 1169/2011 — retained in Great Britain — sets it at a full percentage point either way for ciders, perries and other non-grape fruit wines, sparkling or not. Still grape wine gets half that. So a cider declared at 5.0% may lawfully be anywhere between 4.0% and 6.0%, a spread of fifty per cent on the alcohol in the glass, and the label is not wrong at either end. The figure must be given to no more than one decimal place, and is determined at 20 °C.

Under Regulation (EU) No 1169/2011 on the provision of food information to consumers, beverages containing more than 1.2 per cent alcohol by volume must declare their actual alcoholic strength by volume. The same framework was retained in Great Britain after EU exit and has since diverged in some respects; the strength declaration itself remains.

The threshold explains a labelling pattern readers notice: drinks at or below 1.2 per cent are not required to carry a strength declaration in the same way, which is why low-alcohol products describe themselves in words that vary between markets rather than in a standard figure.

ABV also drives taxation in most jurisdictions, and the tax structure influences the strengths products are made to. The United Kingdom moved its alcohol duty onto a strength-based footing in 2023, which changed the commercial incentives around particular ABV bands. That is a regulatory and commercial fact rather than a health one, but it is part of why certain strengths cluster.

It does not tell you how the drink will taste. Perceived strength depends on sweetness, acidity, tannin and carbonation as well as on alcohol, and a sweet 8 per cent cider can taste less alcoholic than a dry 6 per cent one. This is a well-recognised route to drinking more than intended.

It does not tell you how a given person will be affected. Absorption and metabolism vary with body composition, sex, food, medication, liver function and habituation, and no strength figure predicts an individual’s response.

It does not tell you anything about health. The World Health Organization states that there is no form of alcohol consumption that is risk-free, and its International Agency for Research on Cancer classifies alcoholic beverages, and the ethanol in them, in Group 1 — carcinogenic to humans. A lower ABV means less ethanol per glass; it does not make a drink safe.