Work out priming sugar for carbonation instantly with clear inputs, formula shown and shareable results.
Beer already holds dissolved carbon dioxide that depends on its temperature — about 0.85 volumes at 20 C. Priming sugar need only supply the difference to the target. Around 4 grams of dextrose per litre yields one volume of carbon dioxide; sucrose is more efficient and dried malt extract less.
Residual CO2
Residual volumes = 3.0378 - 0.050062 T(F) + 0.00026555 T(F)^2
Priming sugar
Sugar (g) = (target - residual) x factor x volume, factor 4.0 dextrose, 3.75 sucrose, 4.55 DME
Over-priming can cause bottles to burst under pressure, risking serious injury. Weigh priming sugar accurately and use bottles rated for pressure.
Over-carbonation and potentially exploding bottles. Bottle bombs are a genuine injury risk, which is why priming should be calculated and weighed, not estimated by volume.
Carbon dioxide solubility falls sharply with temperature. Using the temperature at which the beer was warmest since fermentation ended is the safe assumption.