Kombucha · Brewing Calculator
Dial in tea, sugar, starter liquid, and water for any batch size — plus a first-fermentation timing estimate from your room temperature.
Base recipe
70 g/L sugar
Set sugar and starter first, then let temperature estimate your 1F window. Adjust live below.
Live calculator · updates as you type
Your recipe
Keep per-liter values constant when scaling. Timing is an estimate — taste and pH checkpoints matter more than exact day counts.
Kombucha brewing guide
Use the calculator for exact ingredient amounts, then set sugar, starter, and timing decisions in the right order for repeatable first fermentation.
Grams per liter — a practical starting band for first fermentation.
Use enough acidic starter tea to protect the batch early.
Timing shifts with temperature, sugar load, and starter strength.
Keep per-liter values constant when scaling. If your sugar target is 70 g/L and your batch is 3 L, total sugar is 210 g.
Start with batch size, sugar, tea strength, and starter percentage. This gives you a clean baseline before flavoring decisions.
Use the result as your production formula and tune one variable at a time in later batches.
Higher sugar inputs usually extend the tasting window and leave more room for acidity development over time.
Lower sugar batches can finish faster and taste drier, so measure consistently and adjust in small steps.
Using enough acidic starter tea lowers pH early, which protects your batch and helps the culture take over quickly.
When room temperature is cooler, a slightly higher starter percentage can help keep fermentation moving steadily.
Warmer rooms ferment faster and can overshoot acidity quickly. Cooler rooms slow fermentation and usually need longer windows.
Taste checkpoints matter more than exact day counts, so use timing as a guide, not an absolute.
When moving from small to larger batches, keep tea, sugar, and starter ratios consistent first.
Then adjust based on taste and pH logs so your process stays predictable from batch to batch.
Taste for balance and verify your batch is clearly acidic before moving to second fermentation.
If a batch smells off, shows dry fuzzy growth, or lacks acidity, discard it and restart with fresh starter tea.
One printable sheet for all four calculators: 1F targets, sugar planning, scaling, and 2F prep.
Common questions about sugar, starter, tea, and timing.
Most brewers use about 55 to 85 g/L depending on target dryness and fermentation length.
A common range is 10% to 20% of total batch volume, with 15% as a dependable baseline.
Usually 5 to 14 days depending on temperature, starter strength, and sugar concentration.
Yes, but many brewers blend black and green tea for stronger SCOBY performance and balanced flavor.