How to make kombucha at home: the complete guide

Kombucha is a tangy, slightly fizzy drink made from fermented tea. You can brew it at home with just a handful of ingredients, and once you have a starter you can keep making it for the rest of your life. In this article you will learn the process step by step: with a SCOBY, without one, and how to create your own flavour combinations.

Kombucha is a fermented tea drink, probably originating somewhere in East Asia. The exact origins are unknown. You make it by fermenting sweet tea with a combination of bacteria and yeasts. That partnership is called a SCOBY: Symbiotic Culture of Bacteria and Yeast. The lactic acid bacteria, acetic acid bacteria and yeasts convert the sugar into acids, a small amount of alcohol and carbon dioxide. The result is a drink that tastes pleasantly tart, has a light fizz, and lends itself to endless variation.

During fermentation, a jelly-like disc of cellulose forms on the surface. Almost everyone calls this disc “the SCOBY”, but technically it is called the pellicle or biofilm. It is also affectionately known as “the mother”. The real SCOBY is the whole thing: the liquid and the pellicle together. When we refer to “SCOBY” in this article, we mean exactly that: the liquid plus the pellicle, together forming the living starter you need.

This is the standard method and by far the most reliable way to get started.

1. Boil water and brew tea (5-7 grams per litre). Dissolve 50-100 grams of sugar per litre in the hot tea.
2. Let the sweet tea cool completely to room temperature. Tea that is too hot will kill the microorganisms in your starter. Make sure your glass jar is clean. Wash it with hot water and a little washing-up liquid and rinse it well, because detergent residue harms the culture. Also wash your hands before you touch the SCOBY.
3. Pour the cooled tea into the jar. Add roughly 10% mature kombucha (so 100 ml per litre) along with the pellicle.
4. Cover the jar with a cloth and secure it with a rubber band. Do not use a lid: the fermentation needs oxygen.
5. Place the jar somewhere at room temperature or slightly warmer (20-30°C, ideally 25-28°C), out of direct sunlight. Higher temperatures speed up fermentation and produce a more sour result.
6. Let it ferment for 7 to 14 days. After a week, taste regularly with a clean spoon. Pleasantly tart and no longer too sweet? Then it is ready.
   If you measure the pH, do it twice. Right after you set up the brew, the tea should have a pH of 4.2 or lower. If it is higher, add more starter. Finished kombucha has a pH between 2.5 and 3.5. If it already tastes like cider vinegar, use it as a starter or dilute it before drinking.
7. Always save at least 10% of your kombucha along with the pellicle for your next brew.

Want to know more about safe brewing, recognising mould and common problems? Read Is kombucha safe to drink?

You can order a tested, organic kombucha SCOBY from us, guaranteed free of pathogens.

Once your base kombucha is ready, you can do a second fermentation. This is also called F2. During F2, you add flavourings and create carbonation. Ginger kombucha is the most popular variation, but the possibilities are wide open.

Example: ginger kombucha

1. Pour your finished kombucha (without the pellicle) into a pressure-resistant bottle.
2. Add a few slices of fresh ginger, and optionally a slice of lemon.
3. Optionally add a teaspoon of sugar.
4. Seal the bottle tightly.
5. Leave for 1-5 days at room temperature. The yeasts convert the remaining sugar into carbon dioxide.
6. Then put the bottle in the fridge. Cold slows the fermentation down but does not stop it completely. While the bottle is still cold, open it carefully over the sink, keeping it pointed away from your face.

Note: the more fruit or pulp you add, the more pressure can build up in the bottle. So only use proper pressure-resistant bottles, never decorative ones, and keep them in a closed crate or box in summer. Other popular combinations: blueberry-ginger, cranberry-orange, fig with rosemary, or strawberry-pineapple. Looking for more ideas? Read 5 surprising things you can do with kombucha.