Boneyard Tools

Priming Sugar Calculator

Work out how much corn sugar to add at bottling to reach your target carbonation. The tool subtracts the CO2 already in the beer at your temperature.

How to calculate priming sugar

  1. Enter the volume of beer you are bottling in gallons.
  2. Pick a target CO2 level in volumes for the beer style.
  3. Enter the beer temperature, then read the corn sugar to add.

Examples

American ale at room temperature

5 gal, target 2.4 volumes, 68 F
116.9 g corn sugar (4.12 oz)

Frequently asked questions

Why does beer temperature matter?

Warmer beer holds less dissolved CO2. The tool estimates residual CO2 as 3.0378 - 0.050062 x T + 0.00026555 x T squared, then primes for the difference.

What CO2 level should I target?

Most ales sit near 2.2 to 2.6 volumes, while wheat beers and Belgians can reach 3.0 or more. Match the target to the style you are making.

Is this for corn sugar or table sugar?

The result is corn sugar (dextrose). Table sugar (sucrose) is denser, so you would use a little less, roughly 0.91 times the corn sugar weight.

What does already carbonated mean?

If your target is below the CO2 already dissolved at that temperature, no sugar is needed. The tool clamps the amount to zero and flags it.

Can I overcarbonate and make bottle bombs?

Yes. Adding too much sugar or bottling unfinished beer builds dangerous pressure. Weigh the sugar carefully and confirm fermentation is complete first.

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