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Kombucha Calculator

Scale sugar, tea and starter to your batch size using proven per-gallon ratios.

Brew kombucha

Start your first batch: kombucha scoby, brewing jar, flip top bottles.

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Kombucha Brewing Ratios

Kombucha is forgiving once you nail the ratios, and they scale linearly with batch size. The classic per-gallon formula is one cup of sugar, eight bags (or two tablespoons loose) of black or green tea, and two cups of mature starter tea, topped up with water. Multiply everything by your batch size.

Why each ingredient matters

Sugar feeds the culture, not you — most of it is consumed during fermentation. Tea provides nitrogen and tannins the SCOBY needs. Starter tea is the quiet hero: its acidity drops the pH immediately, protecting the young batch from mold and unwanted bacteria while the culture takes over.

Keep it clean and plain

Use plain black or green tea without added oils (skip Earl Grey and flavored blends for the first ferment). Sanitize jars, never use metal for long contact, and let the batch ferment 7-14 days to taste before bottling with flavors for a fizzy second ferment.

Frequently asked questions

How much sugar for a gallon of kombucha?
About one cup of plain white sugar per gallon — the culture eats most of it.
Do I need starter tea?
Yes. It acidifies the batch and protects it from mold while the SCOBY establishes.
What tea works best?
Plain black or green tea without oils or flavorings for the primary ferment.