Kombucha Troubleshooting: 22 Common Problems and How to Fix Them
Something has gone wrong with your kombucha. You’re not sure what, and you’re not sure whether to salvage it or start again.
This kombucha troubleshooting guide covers every common problem — taste issues, carbonation problems, SCOBY appearance concerns and signs of genuine contamination. Each section explains what’s happening, whether it’s actually a problem, and exactly what to do about it.
If you’re new to kombucha and want to understand the full brewing process first, start with my complete beginner’s guide. If something specific has gone wrong and you need answers quickly, find your problem in the sections below.
Taste Problems
1. My kombucha tastes too sweet
What’s happening: Fermentation hasn’t completed yet. The SCOBY hasn’t had enough time or warmth to convert the sugar into acids.
Is it a problem: No — it just needs more time.
What to do: Leave it for another 2–3 days and taste again. If your kitchen is below 20°C, move the jar somewhere warmer — temperature is the biggest factor in fermentation speed. Check my post on how long kombucha takes to ferment for typical timelines at different temperatures.
2. My kombucha tastes like vinegar
What’s happening: Over-fermentation. The bacteria have converted most of the available sugar into acetic acid, pushing the flavour past tangy into sharp and vinegary.
Is it a problem: Not a safety problem — over-fermented kombucha is completely safe. It’s a flavour problem.
What to do: Use this batch as starter liquid for your next brew — it’s excellent for that purpose and highly acidic which protects new batches well. In cooking, it works like apple cider vinegar in dressings, marinades and deglazing. Next batch, reduce fermentation time by 2–3 days and taste from day 7 rather than waiting. Full details in my post on why kombucha tastes like vinegar.
3. My kombucha tastes flat and bland
What’s happening: Either the tea was too weak, the fermentation temperature was too low, or the batch was harvested too early.
Is it a problem: Not a safety problem — just a flavour one.
What to do: Leave it another 2–3 days if it still smells right. For future batches, try stronger tea (3–4 bags per litre rather than 2), ensure the brewing temperature is consistently above 21°C and taste from day 7 to catch it at the right moment.
4. My kombucha tastes metallic
What’s happening: Metal contact during brewing or fermentation. Metal reacts with acidic kombucha, leaching compounds into the liquid.
Is it a problem: Yes — discard this batch.
What to do: Check your equipment. Brief contact with stainless steel during brewing (stirring, pouring through a strainer) is fine. Prolonged contact — fermenting or storing in a metal container, leaving a metal spoon in the jar — is not. Switch to glass, plastic or wood for anything that touches the kombucha for more than a few seconds.
5. My kombucha tastes soapy or perfumed
What’s happening: Almost certainly lavender or another floral flavouring added in too large a quantity during second fermentation. Lavender especially intensifies significantly during fermentation.
Is it a problem: Not a safety problem — just unpleasant.
What to do: This batch is probably not salvageable as a drink but can be used in cooking. Next batch, use significantly less lavender — half a teaspoon of dried culinary lavender per 500ml is the maximum, and starting with a quarter teaspoon and increasing is safer.
6. My kombucha has a strange aftertaste
What’s happening: Usually one of three things — residual soap on equipment, flavoured/herbal/oily tea used in the first ferment, or a stressed SCOBY producing off-compounds (often from a low tannin/caffeine tea like white tea or a weak/young culture).
Is it a problem: Depends on the source, but all three are fixable.
What to do: Rinse all equipment thoroughly with hot water only — no soap residue should remain, and a vinegar rinse before use helps if you’re unsure. Use plain, unflavoured true tea (black, green, white or oolong) for first fermentation, and avoid anything with oils or added flavouring — even trace amounts can throw off the taste. If neither of those is the cause, consider your tea strength: a weak or low-tannin tea (like white tea) can leave a stressed SCOBY producing unusual flavours — switch to black or green tea for a few batches to let the culture recover. If the taste persists across multiple batches after ruling those out, check your water — heavily chlorinated tap water is a common culprit; switch to filtered or dechlorinated water.
Carbonation Problems
7. My kombucha has no fizz after second fermentation
What’s happening: One of seven possible causes — leaking gasket, room too cold, not enough sugar, over-fermented first batch, refrigerated before bottling, not enough time, or too much headspace.
Is it a problem: Not a safety problem — just a disappointing result.
What to do: Work through each possible cause systematically. My full guide on