Kombucha Tools
Brew balanced kombucha,
by the numbers.
Start with the brewing master ratio, dial sugar exactly, scale to your jar, then bottle for fizz. Each tool points to the next one.
Kombucha Quiz
Is your kombucha ready?
Answer three quick questions and get the best next step for your current batch.
Best next move
Open next calculatorThe workflow
Use the kombucha flow in four steps
Build the master recipe
Set tea, sugar, starter, and water.
Dial sugar to taste
Pick a dry, balanced, or sweet profile.
Scale to any vessel
Hold ratios steady from 1L to 25L.
Bottle for fizz
Set 2F sugar or juice and timing.
Troubleshoot
Common kombucha problems these tools solve
Too vinegary
Recheck 1F duration and temperature with the brewing calculator.
Not fizzy after bottling
Use the second fermentation calculator to increase sugar or the 2F window.
Mold risk
Confirm starter ratio and acidity before sealing.
Inconsistent results
Use the batch calculator to lock ratios when scaling.
Slow SCOBY growth
Adjust sugar/starter and keep the jar in an active temp zone.
Weak flavor after 2F
Raise juice percentage or extend 2F based on temperature.
Learn
Kombucha guides
FAQ
Common kombucha questions
The standard ratio is 1 cup of sugar per gallon of tea (about 200g per 4 litres). The SCOBY consumes most of this during fermentation, leaving a mildly sweet, tangy brew. Our sugar calculator adjusts for any batch size.
Typically 7–14 days at room temperature (20–25°C / 68–77°F). Taste-test from day 7. The longer it ferments, the more vinegary it becomes.
Use 10–20% starter liquid (finished kombucha) by volume. For a 1-litre batch, that's 100–200ml of starter. This acidifies the brew immediately and prevents mould growth.
Second fermentation is usually 2–5 days at room temperature, depending on sugar level, bottle seal quality, and temperature. Warmer rooms carbonate faster.
Most brewers get the best balance around 22–25°C (72–77°F). Colder slows fermentation and can leave batches too sweet; hotter ferments quickly and can push vinegar notes.
White sugar is the most reliable option for SCOBY health and consistent fermentation. Honey can work in some methods but often changes microbe balance; stevia does not feed fermentation.
Both are normal. SCOBYs can sink, float, or sit sideways as CO2 develops and releases during fermentation. Position alone is not a health signal.
Taste is the practical signal: move from sweet tea toward balanced tang. Most batches finish in 7–14 days, but temperature and ratio shift timing. Use pH and daily tasting together.
Yes, if it stays healthy and contamination-free. Trim old layers when thick, keep enough starter liquid, and maintain clean handling practices between batches.
Download the free Kombucha Brewing Schedule
Printable companion for all four calculators: 1F tracker, 2F carbonation log, pH chart, and SCOBY health log.
