Cider ABV Calculator

How to work out the ABV of hard cider

Cider yeast ferments nearly all of the sugar in apple juice, so the gravity drop from start to finish tells you its strength.

1. Measure the juice before adding yeast. Store-bought apple juice is usually 1.045 to 1.055, and fresh-pressed juice varies with the apples.
2. Measure again when the gravity holds steady for a few days. Dry ciders usually finish between 0.995 and 1.000.
3. Enter both readings in the Cider ABV tab.

Cider is close to beer strength, so the standard (OG − FG) × 131.25 equation is accurate and is the default. The alternate equation is shown too, for stronger ciders.

Making a stronger cider

Juice at 1.050 ferments to roughly 6.5% ABV. To go higher, dissolve sugar into the juice before fermentation. The Sugar to add tab works out how much from:

• your juice's starting gravity,
• the ABV you want (assuming the cider ferments down to 1.000), and
• your batch size.

Table sugar adds about 46 gravity points per pound per US gallon, dextrose (corn sugar) about 42, and honey about 35. Honey also adds its own flavor; a cider made with honey is called a cyser. For honey-forward batches, see the mead calculator.

Tips for accurate readings

• Degas your sample before reading it, since bubbles push the hydrometer up.
• Correct for sample temperature with the hydrometer temperature correction calculator.
• If you measure with a refractometer, use the refractometer calculator for any reading taken after fermentation begins.

Method and sources

• Standard equation: ABV = (OG − FG) × 131.25. This is the straight-line shortcut most homebrew software uses. The two equations agree closely for normal-strength beer and drift apart as the starting gravity rises.
• Alternate equation: ABV = 76.08 × (OG − FG) / (1.775 − OG) × FG / 0.794. This is Michael Hall's published equation for alcohol by weight, converted to alcohol by volume by multiplying by FG / 0.794 (0.794 is the specific gravity of pure ethanol).
• Sugar additions: each fermentable is counted in gravity points per pound per US gallon. Table sugar (sucrose) is 46, a measured value. Dextrose is 42, because corn sugar is dextrose monohydrate and only about 91% of its weight is sugar. Honey is 35, a working average, since honey's moisture varies and some mead makers use figures up to 42.
• Sugar for a target strength: the target gravity is worked out with the standard equation and a finish of 1.000, then the shortfall in gravity points is converted into sugar.

Every gravity-based ABV is an estimate. A lab measures alcohol directly, and its result can differ slightly from any hydrometer formula.

Sources

• Michael L. Hall, "Brew By the Numbers: Add Up What's in Your Beer," Zymurgy, Summer 1995 (PDF, equation 17 for alcohol by weight)
• Brewer's Friend ABV calculator (shows the standard and alternate equations used here)
• Grainfather: calculating original gravity (1 lb of sucrose in 1 US gallon reads 1.046)
• American Homebrewers Association: mead trivia (honey at about 35 points per pound per gallon)