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Kombucha: how to make the popular fermented brew that everyone’s still talking about

Kombucha, that sweet, bubbly, slightly fermented tea from the east, remains firmly on-trend thanks to claims that it’s great for gut health. What’s more, it’s not too difficult to make, as a trip to London’s Cookery School proves.

Published 27 Feb 2020, 08:54 GMT
Kombucha is made from black tea and the presence of a symbiotic culture of bacteria and yeast, key to the fermentation process.
Photograph by Getty

No one really knows quite what a scoby is, it seems, or where it comes from – that’s what I’ve gleaned from the first 15 minutes of this course.

“Yes, it does look like something from Stranger Things,” says Alice MacKinnon, who’s heading today’s Ferments & Pickles Course for our group of nine.

And you can’t make kombucha without the scoby: kombucha is made from black tea and the presence of a symbiotic culture of bacteria and yeast — hence the name SCOBY — which is key to the fermentation process. Scobys, which can be bought online, “loves sugary, black tea — like an English person!” Alice jokes.

“The scoby is known as the ‘mother’, or ‘mushroom’, which will give you an idea of its appearance,” she adds. “It’s usually dense, round, rubbery and opaque with a mild, vinegar-like smell.” Alice likens kombucha to other fermented foods and drinks, such as kefir or sour dough, which require similar symbiotic cultures. “Kombucha is gnarly. It will survive a lot. When you make it in your environment, it will be made from bacteria in your area.”

The first recorded use of kombucha was in 221 BC in China, although it didn’t acquire its name until AD 415 — in Japan.

Kombucha is simple enough to make. We brew up some black tea, add sugar, then allow it to cool in a sterilised glass jar. The scoby is added (Alice has one she made earlier and gives a bit of it to each of us). It’s then left at room temperature to ferment for one to four weeks, covered with a cloth gauze.

Kombucha does contain a small amount of alcohol — the level will vary according to the brewing time and other variables. Once it’s ready, remove the scoby and flavour the kombucha with fruit or vegetable juice, with a juice-to-kombucha ratio of about 1:8, before storing in the fridge.

Alice recommends drinking around half a cup a day, to avoid becoming “gassy”, and suggests a range of flavour combinations, including ginger-turmeric, rose-hibiscus, lime-cola, pineapple-chili, blueberry-lemon and beetroot-carrot.

If you want to keep a scoby, Alice explains, place it in a glass jar with enough kombucha to cover and store in the fridge, where it will keep for up to two weeks.

After two weeks, replace with fresh kombucha, or feed it again with a fresh batch of sweet tea. Never use metal utensils when preparing kombucha, as the metal can react to the acidity in the kombucha and harm the scoby.

Kombucha made, we’re given a jar, gauze, a scoby and a path to promised gut health. And this is just part one of our course — we still have kimchi, pickled cucumbers and sauerkraut to come.

What next

The three-hour Ferments & Pickles course at the Cookery School costs from £135 per person.

Learning how to make kombucha at the Cookery School in London.
Photograph by Maria Pieri

How to make it: Kombucha

With thanks to Alice MacKinnon

2 tbsp best-quality black tea
500ml boiled, filtered water
200g unbleached cane sugar (not coconut sugar or other sugar replacements)
230ml previously brewed kombucha (you can use store-bought if it’s your first time making kombucha)
1 x scoby
Fruit or vegetable juice, to flavour (optional)


1. Put the tea in 1 x 1-gallon glass jar and pour in the boiling water, then leave to steep for at least 30 mins. Strain out the tea leaves, add the cane sugar and stir well to dissolve. Add the previously brewed batch of kombucha and top up with cold water until there’s a small (maximum 2-inch) gap left between the liquid and the rim of the jar.

2. Check the temperature of the liquid; it should be cool and not too warm. Wash your hands and carefully add the scoby, then cover with a muslin and secure around the neck of the jar. Keep the kombucha at room temperature for at least 10 days. If you want it sweeter, stop the process at that point; if you prefer it to be sourer, leave for 15-20 days.

3. When the kombucha is to your liking, move the scoby and 2 cups of the batch to a clean glass jar. Store the rest in the fridge.

4. Remember to always remove the scoby before flavouring your kombucha. If you’d like to flavour it, combine your chosen fruit or vegetable juice with the fermented kombucha. The ratio of juice-to-kombucha should be around 1:8. Once flavoured, seal the container and leave for around 3 days at room temperature.

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