Priming Sugar Calculator
How much sugar to carbonate your batch in the bottle. Enter batch size, the coldest temperature your beer reached after fermentation, and your target carbonation — get exact grams for corn sugar, table sugar, or DME.
Over-carbonated bottles can explode and cause serious injury. Two rules prevent nearly all of it: 1) confirm fermentation is finished — a stable hydrometer reading over 2–3 days — before bottling, and 2) measure priming sugar by weight and stay within the safety limits this calculator shows. Never exceed ~3.0 volumes of CO₂ in standard 12 oz longneck bottles.
Results
Formula used: –
Dissolve the sugar in 2 cups of boiling water, cool it, and rack the beer gently onto it before bottling.
Why temperature matters
Beer holds dissolved CO₂ from fermentation, and colder beer holds more of it. A lager cold-crashed to 35°F already contains about 1.6 volumes of CO₂ and needs far less priming sugar than an ale that never dropped below 68°F (~0.86 volumes). That's why the calculator asks for the coldest temperature the beer reached after fermentation — not the current room temperature.
Sugar types compared
| Sugar | Relative amount needed | Notes |
|---|---|---|
| Corn sugar (dextrose) | 1.00× (baseline) | The standard; dissolves fast, ferments clean. |
| Table sugar (sucrose) | 0.91× | Slightly more fermentable — use ~9% less by weight. No flavor difference at priming rates. |
| Dry malt extract | ~1.33× | Less fermentable and varies by brand; fine for traditionalists, less predictable. |
Frequently asked questions
How much priming sugar per gallon of beer?
A typical 5-gallon batch at 68°F targeting 2.5 volumes needs about 4.4 oz (125 g) of corn sugar — roughly 0.9 oz per gallon. Exact amounts depend on style, batch size, and temperature.
Can I use table sugar instead of corn sugar for priming?
Yes — use about 9% less by weight than corn sugar. It dissolves easily and tastes identical at priming quantities.
What causes bottle bombs in homebrew?
Too much CO₂ pressure: bottling before fermentation finished, too much priming sugar, or infection. Confirm stable gravity over 2–3 days, weigh your sugar, and respect the ~3.0 volume limit for standard bottles. Full checklist: bottling day checklist.
How long does bottle conditioning take?
Most beers carbonate in 2–3 weeks at ~70°F. Stronger beers take longer. Chill 24–48 hours before opening.