Cider Priming Sugar Calculator

Bottle conditioning works by giving yeast a small, final amount of fermentable sugar sealed inside the bottle. As that sugar ferments, the CO2 it produces has nowhere to escape, so it dissolves back into the cider instead. Get the sugar amount right and you land at your target carbonation; too little leaves the cider flat, too much builds dangerous pressure.

Your cider already holds some dissolved CO2 from the main fermentation, and how much depends on temperature: colder cider holds more, warmer cider holds less. This calculator estimates that residual CO2 from the highest temperature your cider reached after fermentation, then works out how much more you need to reach your target.

The three options shown are alternatives, not a combined dose. Corn sugar (dextrose monohydrate) and table sugar (sucrose) are both nearly fully fermentable; corn sugar needs slightly more by weight because of the water bound into its crystal structure. Apple juice concentrate is a popular natural alternative among cidermakers, but its exact sugar concentration varies by brand (commonly 65-70 Brix), so treat the calculated figure as a starting point and taste-test a small batch first.

Over-priming is a genuine safety issue, not just a quality one. Excess CO2 pressure inside a sealed glass bottle can cause it to fail, sometimes violently. This risk is worth taking seriously with cider specifically, since dry cider left with any unfermented residual sugar can carbonate further than expected once bottled if fermentation was not genuinely complete. Always weigh priming sugar on a scale rather than estimating by volume with a spoon or cup.

Use bottles actually rated for carbonation, such as proper beer or cider bottles or swing-top bottles designed for pressure, never single-use wine or juice bottles. Store conditioning bottles somewhere they can be safely contained if one does fail, and never add extra sugar beyond a calculated dose on the assumption that more carbonation is simply better.