Priming Sugar Calculator

Frequently Asked Questions

How much priming sugar do I need to carbonate beer?

Priming sugar depends on the target CO2 volumes, beer volume, and temperature, since beer already holds residual CO2 based on its warmest fermentation temperature. A typical 5-gal ale at ~2.4 volumes needs roughly 4–5 oz of corn sugar.

What CO2 volumes suit different styles?

British ales are about 1.5–2.0 volumes, American ales 2.2–2.7, and wheat beers or saisons 3.0–4.5. Higher volumes need more priming sugar and stronger bottles.

How does temperature change the dose?

Warmer beer retains less CO2, so it needs more priming sugar to reach the same target. Priming charts use the beer's highest post-fermentation temperature to estimate residual CO2 before adding sugar.

Is corn sugar different from table sugar for priming?

Table sugar (sucrose) is slightly more fermentable than corn sugar (dextrose) by weight, so you use about 10% less of it. Always weigh priming sugar - over-priming risks dangerous over-pressurized "bottle bombs." Drink responsibly.

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Estimates for informational purposes only.

Important Disclaimer: Estimates for informational purposes only.

This calculator provides estimates for informational purposes only. Results are based on assumptions and may not reflect actual outcomes. Consult qualified professionals in relevant fields before making important decisions based on these results.

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How This Calculator Works

Enter the volume of beer you are bottling, your target carbonation level in volumes of CO₂, and the temperature of the beer, then pick your priming sugar. The calculator accounts for the CO₂ already dissolved at that temperature and returns the grams (and ounces) of sugar to add for bottle conditioning. It supports US and metric units and is built for homebrewers bottling a batch.

This is an informational brewing tool, not drinking advice - bottle-conditioned beer keeps fermenting, so prime accurately, store safely, and enjoy responsibly.

Formula / Method

Warm beer already holds dissolved CO₂. Residual CO₂ (volumes) is estimated by 3.0378 − 0.050062·T + 0.00026555·T² with T in °F. The CO₂ you must add is target − residual. Corn sugar (dextrose) is the reference; the dose scales with batch volume and the CO₂ deficit. Other sugars are adjusted by a fermentability factor - table sugar is slightly more efficient (factor 0.91), and dry malt extract less so (1.47) - so the same carbonation needs different weights.

Worked Example

A 5-gallon (≈ 18.9 L) batch at 68°F targeting 2.4 volumes: residual ≈ 3.0378 − 0.050062×68 + 0.00026555×68² ≈ 0.86 volumes, so CO₂ needed ≈ 2.4 − 0.86 = 1.54 volumes. With corn sugar that is roughly 4 × 18.9 × 1.54 ≈ 116 g (≈ 4.1 oz). Dissolve it in a little boiled water, gently mix into the bottling bucket, then bottle - a uniform mix is what prevents flat bottles and the occasional over-carbonated "gusher."

Common Mistakes

Using the cold serving temperature instead of the warmest the beer reached - residual CO₂ is set by that peak temperature.

Over-priming, which risks dangerous over-pressurized bottles - stay within your target style's range.

Not mixing the sugar evenly, giving some flat and some over-carbonated bottles.

Swapping corn sugar for table sugar gram-for-gram without the fermentability adjustment.

Bottling beer that has not fully fermented; residual fermentables add uncontrolled carbonation on top of the priming sugar.

Tips & FAQ

What CO₂ level should I target? British ales 1.5–2.2, American ales 2.2–2.7, wheat beers and many lagers 2.5–3.5 volumes. Why does temperature matter so much? Cold beer holds far more CO₂, so a warm beer needs more sugar to reach the same level. Can I prime with DME? Yes - it adds a touch of body but needs more weight than corn sugar. How long to carbonate? Usually about two weeks at room temperature. Treat the dose as an estimate, never exceed safe bottle pressure, and store conditioning bottles upright in a tub in case one fails.

Frequently Asked Questions

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