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Priming Sugar Calculator

Computes the grams of priming sugar needed to bottle-condition beer to a target carbonation, from the beer volume, target CO₂ volumes and the residual CO₂ already dissolved at the beer's post-fermentation temperature, using the CO₂ yield of dextrose, sucrose, dry malt extract or honey.

When to use

You are bottling homebrew and need the amount of priming sugar for a batch and carbonation level, e.g. 20 L of ale to 2.4 volumes.

Do not use when: You force-carbonate in a keg (use a pressure/temperature carbonation chart instead) or the beer is still fermenting, since the residual CO₂ estimate assumes fermentation is complete.

Formula

T_F = beer_temperature_c × 9/5 + 32; residual = 3.0378 − 0.050062·T_F + 0.00026555·T_F²; CO₂_g = max(0, target_co2_volumes − residual) × beer_volume_l × 1.96; sugar_g = CO₂_g / yield; yield (g CO₂ per g): dextrose monohydrate 2 × 44.01 / 198.17 = 0.4442, sucrose 4 × 44.01 / 342.30 = 0.5143, DME 0.68 × 0.5143 = 0.3497, honey 0.80 × 2 × 44.01 / 180.16 = 0.3909

The residual-CO₂ polynomial is the standard homebrewing fit for beer at equilibrium with 1 atm of CO₂ after fermentation; 1 volume of CO₂ per litre weighs 1.96 g. Sugar yields follow the fermentation stoichiometry (1 mol hexose → 2 mol CO₂); the 68 % fermentable fraction for DME and 80 % sugar content of honey are typical assumptions and vary by product.

Inputs

ParameterTypeUnitRequiredDescription
beer_volume_lnumberLyesVolume of beer being bottled, in litres (1 US gal = 3.785 L). Range: > 0, ≤ 10000
target_co2_volumesnumbervolumes CO₂default 2.4Desired carbonation in volumes of CO₂: British ales 1.5–2.0, American ales 2.2–2.7, lagers 2.4–2.6, Belgian ales 1.9–2.4, wheat beers 3.3–4.5. Range: ≥ 0.5, ≤ 5
beer_temperature_cnumber°CyesHighest temperature the beer reached after fermentation finished (this sets how much CO₂ is still dissolved), not the bottling temperature if the beer was cold-crashed afterwards. Range: ≥ -2, ≤ 40
sugar_typeenum: corn_sugar_dextrose_monohydrate | table_sugar_sucrose | dry_malt_extract | honeydefault corn_sugar_dextrose_monohydrateType of fermentable used for priming; sets the grams of CO₂ produced per gram.

Outputs

OutputTypeUnitDescription
temperature_fnumber°Fbeer_temperature_c converted to Fahrenheit (the residual-CO₂ fit uses °F).
residual_co2_volumesnumbervolumes CO₂CO₂ still dissolved in the beer at that temperature after fermentation.
co2_to_add_volumesnumbervolumes CO₂target_co2_volumes − residual_co2_volumes (0 if the beer is already at or above target).
co2_gramsnumbergGrams of CO₂ the priming sugar must generate (1.96 g per volume per litre).
co2_yield_g_per_gnumberg CO₂ / gGrams of CO₂ produced per gram of the chosen sugar.
sugar_gramsnumbergSugar to dissolve in a little boiled water and mix into the whole batch before bottling.
sugar_grams_per_liternumberg/LSugar per litre of beer (for priming individual bottles: multiply by the bottle volume in litres).
sugar_oznumberozSame amount in ounces by weight.
style_carbonation_notestringWhere the target sits among typical style carbonation ranges, with a bottle-pressure caution above 3 volumes.

Example

20 L to 2.4 volumes, beer at 20 °C, corn sugar: {"beer_volume_l":20,"target_co2_volumes":2.4,"beer_temperature_c":20,"sugar_type":"corn_sugar_dextrose_monohydrate"} → {"temperature_f":68,"residual_co2_volumes":0.861,"co2_to_add_volumes":1.539,"co2_grams":60.3,"sugar_grams":135.8,"sugar_grams_per_liter":6.79,"sugar_oz":4.79}

19 L wheat beer to 3.5 volumes, beer at 22 °C, DME: {"beer_volume_l":19,"target_co2_volumes":3.5,"beer_temperature_c":22,"sugar_type":"dry_malt_extract"} → {"residual_co2_volumes":0.815,"co2_grams":100,"sugar_grams":285.9,"sugar_grams_per_liter":15.05}

GET https://tttkmbb.com/api/v1/calculate/priming-sugar?beer_volume_l=20&target_co2_volumes=2.4&beer_temperature_c=20&sugar_type=corn_sugar_dextrose_monohydrate

Machine access

Sources

FAQ

Which temperature do I enter if I cold-crashed the beer?

The warmest temperature the beer sat at after fermentation ended. CO₂ lost at that temperature does not come back when the beer is chilled, so entering the cold temperature would under-prime the batch.

How much is that in table sugar?

Sucrose yields about 16 % more CO₂ per gram than corn sugar (dextrose monohydrate), so use about 0.86 × the corn-sugar weight; run the calculator with sugar_type=table_sugar_sucrose for the exact figure.

Is there a risk of bottle bombs?

Standard 12 oz / 330 ml bottles are typically rated to about 3 volumes; above that use heavy Belgian-style or champagne bottles. Bottling a beer that has not finished fermenting is the most common cause of over-carbonation.

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