Short answer
Kombucha is a fizzy, slightly tart drink made by fermenting sweetened black or green tea. The fermentation uses a SCOBY, a living culture of bacteria and yeasts, plus a little starter liquid from a previous batch. Most of the sugar is used up during fermentation, and the result is a drink with live microbes, natural acids and a little alcohol and caffeine.
Where it comes from
Kombucha has been brewed for a long time. Records from East Asia go back many centuries, and the drink later spread to Russia and Europe. Its exact origin is unclear. Commercial production began in the United States in the mid-1990s, and it is now sold in many countries.
What’s in it
Kombucha is made from four basic ingredients: tea, sugar, water and a SCOBY. The starter liquid from a previous batch is added to help the brew begin safely. During fermentation, the yeast turns sugar into alcohol and carbon dioxide, and the bacteria turn the alcohol into acids. The result is less sugar than the sweet tea you started with, though flavoured versions can add sugar back in.
How it’s made
Kombucha is made in two stages.
- First ferment: sweet tea, a SCOBY and starter liquid sit at room temperature for about one to two weeks. The brew gets more sour the longer it sits, and it is ready when it tastes right to you. For the full recipe, see how to make kombucha at home.
- Second ferment: the SCOBY is removed, and the kombucha is bottled with flavouring. The bottles are left for a few days, which makes the drink fizzy. For a full guide, see how to flavour kombucha.
Caffeine and alcohol
Kombucha contains a small amount of caffeine from the tea, less than a cup of black or green tea. Fermentation also produces small amounts of alcohol. In the United States, drinks sold as non-alcoholic must contain less than 0.5% alcohol. Labelling rules differ by country, so check the label where you live. If a glass leaves you feeling light-headed, see why you might feel buzzed after kombucha.
Health: what’s known and what isn’t
Kombucha contains live microbes, natural acids and some compounds from the tea. Many of the health benefits people talk about have not been researched well. Much of the research so far is in the lab or in animals. Kombucha is a fermented drink with interesting ingredients. It is not a treatment for any condition, and it is not a replacement for medical care.
For a closer look at the microbes, see what bacteria ferment kombucha.
Who should check with a doctor first
- People who are pregnant or breastfeeding
- Young children
- People with a weakened immune system
- People with kidney disease, or who are following a special diet
- Anyone with a health condition they are unsure about
For the kidney question in more detail, see is kombucha good for kidneys.
Buying or brewing?
Shop-bought kombucha is convenient. Check the label for sugar, alcohol and any added juice. Brewing your own is cheaper, and you control the ingredients, but it needs clean equipment, safe bottling and daily checks for pressure and mould. For a complete flavour guide, see how to flavour kombucha.
For the SCOBY itself, including how long it can be stored between batches, see how long a SCOBY can sit in starter liquid.