Our Priming Sugar Calculator tells you exactly how much corn sugar, table sugar, DME or honey to add to your homebrew batch for perfect bottle carbonation — no flat beer, no gushers.
Priming Sugar Calculator
Priming Sugar Formula
Corn Sugar (g) = 15.195 × Volume (L) × (Desired CO2 − Residual CO2)
Residual CO2 is the carbonation already dissolved in your beer from fermentation, based on the temperature it reached: Residual CO2 = 3.0378 − (0.050062 × °F) + (0.00026555 × °F²). Warmer beer holds less CO2, so it needs more priming sugar; colder beer holds more and needs less.
What Is Priming Sugar and Why You Need It?
Priming sugar is the small amount of fermentable sugar added to homebrewed beer right before bottling. The leftover yeast in the bottle eats this sugar and produces CO2 as a byproduct — since the bottle is sealed, that CO2 has nowhere to go except into the beer, creating natural carbonation. Add too little and the beer comes out flat; add too much and you risk gushers or, in rare cases, bottle bombs.
How Much CO2 Should You Target by Beer Style?
| Beer Style | CO2 Volumes |
|---|---|
| British Ales | 1.5 – 2.0 |
| American Ales / IPA | 2.2 – 2.7 |
| Stouts / Porters | 1.7 – 2.3 |
| German Lagers | 2.4 – 2.8 |
| Belgian Ales | 2.8 – 3.5 |
| Wheat Beers | 3.0 – 4.5 |
Priming Sugar Conversion Reference (5-Gallon Batch at 68°F, Target 2.4 Volumes)
| Sugar Type | Amount Needed |
|---|---|
| Corn Sugar (Dextrose) | ~115 g (4.1 oz) |
| Table Sugar (Sucrose) | ~104 g (3.7 oz) |
| Dry Malt Extract (DME) | ~153 g (5.4 oz) |
| Honey | ~121 g (4.3 oz) |
Common Mistakes When Priming Beer
- Using the fermentation temperature, not the highest temp the beer reached. Residual CO2 depends on the warmest point during fermentation, not the current cold temperature after a cold crash.
- Adding dry sugar straight into the bottling bucket. Always dissolve priming sugar in a small amount of boiling water first, then cool and mix gently into the beer to avoid uneven carbonation.
- Bottling too soon. Make sure fermentation is fully complete (stable gravity readings 2-3 days apart) before adding priming sugar, or you risk over-carbonation.
- Ignoring batch size loss. Use your actual final volume going into bottles, not the original recipe target volume.
FAQs
How much priming sugar per gallon of beer?
For a typical 2.4 volumes of CO2 at 68°F, you need roughly 0.85 oz (24 g) of corn sugar per gallon. Use the calculator above for your exact temperature and target carbonation.
Can I use table sugar instead of corn sugar for priming?
Yes. Table sugar (sucrose) works fine and needs about 10% less by weight than corn sugar, since it’s a slightly more concentrated source of fermentable sugar.
What happens if I add too much priming sugar?
Over-carbonation causes gushers when you open the bottle, and in extreme cases can build enough pressure to crack or burst glass bottles. Always measure rather than estimate.
How long does priming sugar take to carbonate beer?
Most homebrew carbonates within 1-2 weeks at room temperature (68-72°F), though some styles benefit from 3-4 weeks of conditioning for fuller carbonation and flavor.
Do I need priming sugar if I force carbonate with CO2?
No. Priming sugar is only for bottle conditioning. If you’re kegging and force carbonating with a CO2 tank, skip priming sugar entirely.