"What is kombucha, actually?" and "Is kombucha healthy?" are the two questions we hear most at BOUCHE. Most answers online are either too vague or too grand. Here is our honest version: what is proven, and what (so far) is not.

What is kombucha?

Kombucha is fermented, sweetened tea. The base is usually black or green tea with added sugar. A culture of bacteria and yeast, the SCOBY (Symbiotic Culture of Bacteria and Yeast), ferments the tea over several days to weeks. The result is a lively, slightly tart drink.

Its roots probably lie in East Asia, likely in today's China or Manchuria. Via Russia and Eastern Europe it reached Western Europe, almost disappeared, and has been making a comeback for some years, including here in Berlin.

How fermentation works

Yeasts break down the sugar in the sweetened tea, producing CO₂ and small amounts of alcohol. Acetic and lactic acid bacteria then convert that alcohol into organic acids. The longer fermentation runs, the drier and more tart the drink becomes.

What is actually in the bottle

Kombucha is not a uniform product. In general, finished kombucha contains organic acids (mainly acetic, gluconic and lactic acid), some residual sugar, polyphenols from the tea, carbonation and traces of alcohol, typically between 0.1 and 2% vol. depending on the source. BOUCHE sits between 0.2 and 0.5% vol. At BOUCHE we add the carbonation after fermentation, partly to hold the aroma. Whether live cultures are still in the bottle depends on whether the kombucha is stabilised afterwards.

Pasteurised or raw: an honest comparison

Pasteurised or heat-stabilised kombucha is briefly heated after fermentation. That makes it shelf-stable and consistent from bottle to bottle, but it also kills the live bacteria and yeast. What remains is the flavour, the organic acids and the polyphenols. Raw kombucha is not heated: the live cultures remain, but it must be kept cold throughout, and flavour and alcohol content can keep shifting in the bottle.

BOUCHE ferments fully in a closed tank with our own liquid SCOBY culture, is centrifuged, and gets a short flash stabilisation directly after filling. So the bottle contains no live cultures in any meaningful amount. BOUCHE is not a probiotic or "living" drink. What stays is what makes the flavour: organic acids, tea polyphenols and aroma. For us that is a deliberate choice, and it keeps the alcohol reliably between 0.2 and 0.5% vol.

Sugar compared to soft drinks

Not every kombucha is automatically low in sugar. Short fermentation or sweetening with juice afterwards leaves more sugar in the bottle. "Fermented" is not a synonym for "sugar-free". BOUCHE is fermented longer and sweetened with restraint, so much less sugar remains than in a classic soda.

What is proven, and what isn't

Reasonably well established: fermentation produces organic acids; raw kombucha contains live cultures while heat-stabilised kombucha like BOUCHE does not; tea provides polyphenols; kombucha contains small amounts of alcohol.

Not scientifically proven, even if it often sounds that way online: that kombucha strengthens the immune system or heals disease, helps with weight loss, lowers cholesterol, or "detoxes". The German Nutrition Society (DGE), health insurers AOK and DAK and the consumer advice centre agree. BOUCHE is a drink to enjoy, not a medicine. "Probiotic" is also a regulated health claim under EU law, and BOUCHE contains no live cultures in the bottle anyway. More in Probiotics and gut health.

Who should be careful

Because of the acidity and the small amount of alcohol, kombucha is not for everyone. People with a severely weakened immune system should check with their doctor. During pregnancy and breastfeeding: BOUCHE contains between 0.2 and 0.5% vol. alcohol. Whether that works for you is your decision, ideally after talking to your doctor or midwife. Kombucha is not recommended for children because of its alcohol content.

Is kombucha vegan?

Yes. Tea, water, sugar and a microbial culture. The SCOBY is a community of bacteria and yeast, not an animal product.

Where to find BOUCHE

BOUCHE is brewed in Berlin. Find us in selected shops and cafés via our store locator, or directly online.