Priming Sugar Calculator
Priming sugar is the measured dose of fermentable sugar added at bottling to carbonate beer through a final sealed fermentation. The amount depends on target CO2 volumes, beer volume, and the residual CO2 already dissolved — which is set by the beer's temperature. The formula is sugar (g) = (target volumes − residual volumes) × liters × 1.96 / sugar yield.
The temperature matters more than people expect — warm beer already holds less CO₂, so it needs more sugar to reach the same carbonation.
How bottle priming works
Beer that has finished fermenting still holds some dissolved CO2. Adding a measured amount of sugar at bottling gives the remaining yeast one last small fermentation, and because the bottle is sealed the CO2 it produces dissolves into the beer.
The amount you need depends on three things: how much beer there is, how carbonated you want it, and how much CO2 is already in there — which is set by the warmest temperature the beer has been held at since fermentation ended.
sugar (g) = (target volumes − residual volumes) × liters × 1.96 / yield
Where 1.96 is grams of CO2 per liter per volume, and the yield is how much CO2 each gram of sugar produces: 0.462 for corn sugar, 0.510 for table sugar, 0.370 for dry malt extract, 0.385 for honey.
How much sugar for 19 liters (5 US gallons) at 20 °C
| CO₂ volumes | Corn sugar | Table sugar | DME |
|---|---|---|---|
| 2.0 | 92 g | 83 g | 115 g |
| 2.2 | 108 g | 98 g | 135 g |
| 2.4 | 124 g | 112 g | 155 g |
| 2.6 | 140 g | 127 g | 175 g |
| 2.8 | 156 g | 142 g | 195 g |
| 3.0 | 172 g | 156 g | 215 g |
Carbonation levels by style
- 1.5–2.0 volumes — British ales, barleywine, anything served on cask
- 1.7–2.3 volumes — porters and stouts
- 2.2–2.8 volumes — American ales and IPAs
- 2.4–2.8 volumes — lagers
- 3.0–4.5 volumes — German wheat beers, Belgian ales, lambic
Two ways to get this wrong
Using the wrong temperature. The figure that matters is the highest temperature the beer reached after fermentation finished, not the temperature at bottling. If it sat at 22 °C for a week and you chilled it the night before, use 22.
Bottling before it is finished. Priming sugar assumes fermentation is complete. If it is not, the remaining sugar carbonates the bottle as well, and the results range from gushers to broken glass. Two identical gravity readings three days apart is the check.
Priming Sugar Calculator — questions
How much priming sugar for 5 gallons?
For 19 liters of American-style ale at 2.4 volumes, about 124 g (4.4 oz) of corn sugar, assuming the beer has been sitting near 20 °C. Colder beer holds more CO₂ already and needs less; warmer beer needs more.
Can I use table sugar instead of corn sugar?
Yes. Sucrose yields slightly more CO₂ per gram than dextrose, so use about 10% less by weight. It does not affect the flavor at these quantities, whatever you may have read.
Why did my bottles come out flat?
Usually cold conditioning — yeast will not carbonate at cellar temperature. Leave the bottles somewhere around 20 °C for two weeks before you judge them. Failing that, the yeast may have been dropped out by long cold conditioning or fining.
Priming is part of the brew day, not a separate page
Brewgravity's brew-day planner includes a priming step with the sugar amount already calculated from your recipe — no retyping volumes and temperatures.
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