ABV Calculator

The simple form is (OG − FG) × 131.25. At 1.050 down to 1.010 that is 5.25%. It is a linear approximation and it drifts as gravity rises.

The simple one below about 7% ABV, where the two agree closely. Above that, the high-gravity form corrects the drift — and quoting which one you used matters when comparing numbers with someone else.

The percentage of the original sugar the yeast consumed, calculated from hydrometer readings. It is called apparent because alcohol is less dense than water, so the hydrometer reads low and the true figure is a few points lower.

Common causes are a fermentation temperature that dropped, a yeast strain at its alcohol tolerance, or unfermentable sugars from a high mash temperature. Rousing the yeast and warming the vessel fixes most stalls.

Mostly from alcohol at about 7 kcal per gram, plus residual sugar. A drier beer at the same ABV has fewer calories than a sweet one, though alcohol dominates either way.

A fixed mass of pure alcohol, and the mass differs by country — 10 g in the UK and Australia, 14 g in the US. That is why the same bottle is a different number of units depending on where you are.

Float it in a sample at the calibration temperature, usually 20 °C, and read at the bottom of the meniscus. Temperature correction matters — a warm sample reads low.

It measures refractive index from a couple of drops, which is convenient. Alcohol changes refraction, so post-fermentation readings need a correction formula and disagree with a hydrometer without it.

Temperature dropping out of the yeast's range, alcohol tolerance being reached, or unfermentable sugars from a high mash temperature. Rousing the yeast and warming the vessel fixes most stalls.

Apparent uses the hydrometer figure, which alcohol makes read low. Real attenuation corrects for that and is a few percentage points lower — recipes almost always quote apparent.

Slightly, by perhaps 0.2 to 0.5% as the priming sugar ferments. It is usually within the measurement error of the original reading.

For personal consumption in most countries, up to a volume limit, with distillation treated very differently from brewing. Selling it is regulated everywhere — check your own jurisdiction.