Priming Sugar Calculator
Calculate how much priming sugar you need for bottle conditioning. Enter your batch volume, desired carbonation, and beer temperature.
CO2 Volumes by Beer Style
Not sure what CO2 level to target? Here are typical ranges by style.
| Style | CO2 (volumes) |
|---|---|
| British Ales | 1.5 - 2 |
| American Ales / IPAs | 2.2 - 2.7 |
| Porters & Stouts | 1.7 - 2.3 |
| Belgian Ales | 2.5 - 4.5 |
| Wheat Beers | 2.8 - 4 |
| Lagers / Pilsners | 2.4 - 2.8 |
| Saisons | 3 - 4.5 |
| Barleywine | 1.5 - 2.3 |
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How Priming Sugar Works
After fermentation, your beer is flat. There is some dissolved CO2 left over from fermentation, but not enough for the fizz you want in the finished beer. Priming sugar fixes this.
You dissolve a measured amount of sugar into boiled water, mix it gently into your fermented beer, then bottle it. The residual yeast still in the beer ferments this small amount of sugar, producing CO2. Because the bottle is sealed, the CO2 dissolves into the beer instead of escaping. This is called bottle conditioning.
The key variables are:
- Batch volume — more beer needs more sugar.
- Target CO2 volumes — how fizzy you want it. British ales are typically lower (1.5-2.0), Belgian styles and wheat beers higher (2.5-4.5).
- Beer temperature — colder beer holds more residual CO2 from fermentation. The calculator subtracts this residual CO2 from your target so you only add what is needed.
- Sugar type — different sugars have different fermentability by weight. Table sugar (sucrose) is the baseline. Corn sugar (dextrose) is about 91% as dense, so you need more. DME and honey are less fermentable still.
The formula calculates residual CO2 from temperature, subtracts it from your target, then works out how many grams of each sugar type would produce the remaining CO2 needed.
Frequently Asked Questions
How much priming sugar do I need for homebrew?
It depends on your batch volume, desired carbonation level, and beer temperature. For a typical 19-litre batch targeting 2.4 volumes of CO2 at 20°C, you need roughly 100-120g of table sugar. Use the calculator above for an exact figure.
What is priming sugar?
Priming sugar is sugar added to fermented beer just before bottling. The residual yeast in the beer ferments this sugar, producing CO2 that carbonates the beer naturally in the sealed bottle. This is called bottle conditioning.
Can I use table sugar instead of corn sugar for priming?
Yes. Table sugar (sucrose) works well for priming and is the most readily available option. Corn sugar (dextrose) is roughly 91% as fermentable by weight, so you need about 10% more. Both produce clean carbonation with no off-flavours at priming quantities.
Why does beer temperature matter for priming?
Beer already contains dissolved CO2 from fermentation. Colder beer holds more residual CO2 than warmer beer. The priming calculator subtracts this residual CO2 from your target to determine how much additional CO2 (and therefore sugar) you need. Getting the temperature wrong can lead to over-carbonation or flat beer.
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