This recipe turns one gallon (about 3.8 L) of finished kombucha into a sparkling, lightly alcoholic, ale-style drink. If the yeast ferments all of the sugar, 1 cup of sugar works out to roughly 3% ABV, and about a pound gets you closer to 6%.
You need finished kombucha and a SCOBY from a previous batch. For the full process and safety notes, see How to Homebrew Kombucha Beer.
Ingredients (1 gallon)
- About 1 gallon (3.8 L) finished kombucha, with the SCOBY removed
- 1 cup (about 200 g) table sugar, dissolved in 1 cup of boiled, then cooled, water
- About 5 g dry ale or champagne yeast (roughly one packet, or about 2 teaspoons)
- Optional: a small amount of flavoring or dry hops (see below)
- 2 cups of finished kombucha, to keep the SCOBY in
Choosing your yeast
- Safale US-05 is a neutral American ale yeast, so the kombucha flavor leads. Northern Brewer suggests it.
- Red Star Premier Cuvée is a champagne yeast, for more lift and effervescence.
- Lalvin D47 is an alcohol-tolerant wine yeast with a slightly citrus note. The Zymurgy hard kombucha recipe uses it.
Kombucha is acidic and can slow yeast, so brewers add more yeast than they would for beer. About 5 g (one packet, or roughly two teaspoons) for a gallon is a common starting point. Follow the rehydration and temperature directions on your own packet, because strains differ.
Sugar and strength
Sugar sets how strong the batch can get. Here are two common sizes, using the rough rule that 100 g of sugar per gallon adds about 1.4% ABV if fully fermented:
| Batch | Sugar per gallon | ABV added (approx.) |
|---|---|---|
| Lighter | 1 cup (about 200 g) | about 3% |
| Stronger | about 1 lb (about 450 g) | about 6% |
Treat these as upper estimates. If the yeast stops early, the batch will be weaker and sweeter, and leftover sugar can build pressure in the bottle. For the math and how to measure your batch, see how much alcohol is in homemade kombucha beer.
Equipment
- A food-safe fermenter with room to spare, so foam does not blow out
- An airlock and bung
- Sanitizer and a funnel
- A hydrometer and test jar
- PET bottles with screw caps
- Optional: pH strips
Method
- Finish the base batch. Let your kombucha ferment until it tastes tart and only faintly sweet.
- Remove the SCOBY. Store it in a covered container with 2 cups of the finished kombucha. If the container is sealed, loosen the lid every couple of days to release carbon dioxide.
- Make the sugar solution. Dissolve the sugar in boiled water, then let it cool to room temperature.
- Add the sugar and take a reading. Stir the sugar solution into the kombucha in the sanitized fermenter. Take a hydrometer reading. That is your starting gravity.
- Add the yeast. Rehydrate it as the packet says. When it is foamy, stir it in.
- Seal and ferment. Put on the lid and airlock. Keep the batch steady within your yeast’s temperature range.
- Wait and check. Expect roughly one to two weeks. Keep checking the hydrometer until the reading stops changing for a few days.
- Flavor (optional). See the next section.
- Bottle and chill. Fill PET bottles, leave them at room temperature, squeeze them daily, and refrigerate them once they feel firm.
Optional flavors
- Herbs and spices: steep for a day or two, then remove them. Spearmint and lemon balm are common choices.
- Fruit: adds sugar. Use a small amount, or leave it out of the first batch, because it can push pressure too high.
- Dry hops: use a light hand on the first batch. Hops add bitterness and aroma.
Timing and when it’s done
- Days 1 to 3: the airlock should start to bubble. If it does not, see troubleshooting.
- About a week: check the hydrometer. Some batches are close to done by then, but the time depends on temperature and sugar.
- Done: when the reading holds steady over a few days. A taste sample also helps, because the batch tastes drier and less sweet as the sugar runs out.
Bottling and carbonation
Bottle in PET bottles, not glass, and check the pressure by hand. Once the bottles feel firm, refrigerate them. For the squeeze test and what to do with a bottle that feels rock-hard, see the bottling section of How to Homebrew Kombucha Beer.
Troubleshooting
- No bubbling after two or three days: check that the yeast was fresh and that the room is within range. Give it time. If nothing changes after a week or two, add a fresh dose of yeast.
- Still very sweet: keep it fermenting and check the reading. Next batch, use the lighter sugar amount.
- Too strong or too dry: use less sugar next time, and chill the batch once it tastes right.
- Bottles over-pressurized: chill them, open them slowly over a sink, and go lighter on sugar and fruit.
Next steps
To measure your batch, read how much alcohol is in homemade kombucha beer. For the whole process and safety notes, see How to Homebrew Kombucha Beer. If you would rather keep alcohol minimal, see how to brew non-alcoholic kombucha.