Kombucha Sugar & Tea Ratio Calculator
Scale a kombucha batch to your jar — sugar, tea and starter liquid in the tested ratios that keep the ferment healthy and safe.
How it works
Sugar = sugar/L × litres · Tea = tea/L × litres · Starter ≈ 10% of the tea volume
Kombucha ferments sweet tea with a SCOBY, which consumes most of the sugar over 7–14 days. A standard recipe is about 50–80 g of sugar and 5–6 g of tea per litre, plus roughly 10% mature starter liquid to acidify the batch and protect it from mould. The acidic start is the key safety step; do not skip or shrink the starter to “save” it.
Worked example
For 1,000 ml of tea at 70 g/L sugar and 6 g/L tea, you dissolve 70 g of sugar, steep 6 g of tea, and add about 100 ml of starter liquid (10%). After 7–14 days it ferments into roughly 1,100 ml of kombucha.
Frequently asked questions
How much starter liquid do I need?
Aim for about 10% of the batch volume in mature, unflavoured kombucha from a previous batch or a bottle of raw kombucha. It lowers the pH quickly, which suppresses mould and gives the culture a safe head start.
Can I reduce the sugar to make it less sweet?
The sugar is food for the culture, not just sweetness — most of it is consumed during fermentation, and the finished drink is far less sweet than the starting tea. Cutting sugar below about 50 g/L can starve the SCOBY; ferment longer or add a second ferment for a drier result instead.
How long should the first ferment run?
Usually 7–14 days depending on temperature and taste. Warmer ferments faster. Start tasting around day 7: stop when the balance of sweet and tart suits you, then bottle for an optional second ferment to carbonate.
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This calculator is for educational purposes. Double-check important results before acting on them.