Your priming plan
— priming sugar
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Priming sugar
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Dissolve the sugar in a little warm water before adding it, so it distributes evenly rather than settling in one bottle.
Bottles
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Pressure risk
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Carbonation is estimated at roughly 2 g of sugar per litre per volume of CO2, with residual carbonation subtracted for brews that are already sparkling. This is a planning figure. Bottle-conditioned kombucha keeps fermenting in the bottle, so the only reliable control is temperature and time: chill early, check often, and never leave bottles somewhere warm.
Getting carbonation right without the bang
Volumes of CO2
Carbonation is measured in volumes — the amount of gas dissolved in the liquid. Beer sits around 2.2–2.6, soft drinks around 3.5. Kombucha is happiest between 2.0 and 3.0.
The right bottle
Use bottles designed for carbonated drinks: swing-top beer bottles or pressure-rated glass. Decorative bottles, repurposed juice bottles and thin glass are not built for pressure.
Flavour adds sugar
Fruit and juice bring their own fermentable sugar. Adding a full priming dose on top of a sugary flavouring is the most common route to an over-carbonated bottle.
Time and temperature
Bottle conditioning happens at room temperature. One to three days is usually enough, and warm weather can cut that in half. Refrigeration stops the process.
Flavouring quantities at a glance
Rough starting points per litre of second fermentation. Adjust to taste after the first batch.
| Flavouring | Per litre | Sugar it adds | Notes |
|---|---|---|---|
| Fresh ginger | 10–15 g | Low | Sharp and aromatic; grate or slice thinly |
| Berries | 50–70 g | Moderate | Crush lightly; strain if you want clarity |
| Citrus zest | 20–30 g | Low | Use unwaxed fruit; avoid the bitter pith |
| Stone fruit | 60–80 g | Moderate to high | Reduce priming sugar accordingly |
| Tropical fruit | 70–80 g | High | Ferments vigorously — watch the pressure |
| Fresh herbs | 5–8 g | Very low | Bruise gently to release the oils |
| Dried flowers | 6–10 g | Very low | Steep in hot water and cool first |
| Fruit juice | 80–100 ml | High | Use 100 % juice, not squash |
Bottle bombs are preventable. If you are new to carbonating kombucha, start with the gentle target, use swing-top bottles, and chill the batch after one day. Open the first bottle over a sink. If it gushes, refrigerate the rest immediately and open them cold and slowly.
About these calculators
The formulas behind these tools are widely published home-brewing approximations, not laboratory-grade models. They are intended to point you in the right direction and to make your own batches repeatable — they are not a substitute for measuring your brew, and they cannot guarantee a result.
- Every calculator runs entirely in your browser. Nothing you type is transmitted, logged or stored.
- Figures are approximate. Tea strength, sugar type, room temperature, vessel shape and the health of your culture all shift the outcome.
- pH is a safety-relevant measurement. Treat the estimator as a planning aid only, and confirm with strips or a calibrated meter before bottling.
- Finished kombucha contains trace alcohol and caffeine. It is not suitable for children, and anyone who is pregnant, breastfeeding, immunocompromised, diabetic or taking medication should consult a healthcare professional before drinking it.
- Kombucha is a food, not a medicine. Nothing on this site claims it treats, cures or prevents any disease.