A 1 litre batch uses 50 g of sugar, 2 tea bags and 120 ml of starter, with the rest as sweet tea. A 6 litre batch uses 300 g of sugar, 12 tea bags and 720 ml of starter. The same ratios work at any size, but bigger batches need bigger jars, more SCOBYs and a little more planning.
The Ratio Behind Every Batch
- Sugar: about 50 g per litre of total batch volume. Most recipes fall between 50 and 80 g per litre, so 50 g is a sensible place to start. How much sugar for 1 litre of kombucha explains why.
- Tea: about 2 black or green tea bags per litre.
- Starter: about 10 to 15% of the total volume. In the table below, the starter is 12%, which is 120 ml per litre.
- Water: the rest of the total volume, which becomes the sweet tea once the sugar and tea are added.
- Headspace: choose a jar that is at least about a quarter bigger than the batch, so there is room at the top for the SCOBY to form.
Batch Size Table
“Total batch” means everything in the jar, starter included. The figures are rounded for easy kitchen measuring.
| Total batch | Tea bags | Sugar | Starter | Water | Jar size |
|---|---|---|---|---|---|
| 1 litre | 2 | 50 g (about ¼ cup) | 120 ml (about ½ cup) | about 880 ml | 1.5 litre jar |
| 2 litres | 4 | 100 g (about ½ cup) | 240 ml (1 cup) | about 1.76 litres | 2.5 litre jar |
| 3 litres | 6 | 150 g (about ¾ cup) | 360 ml (about 1½ cups) | about 2.64 litres | 4 litre jar |
| 4 litres | 8 | 200 g (1 cup) | 480 ml (2 cups) | about 3.5 litres | 5 litre jar |
| 5 litres | 10 | 250 g (about 1¼ cups) | 600 ml (about 2½ cups) | about 4.4 litres | 7 litre jar |
| 6 litres | 12 | 300 g (1½ cups) | 720 ml (3 cups) | about 5.3 litres | two 4 litre jars |
| 8 litres | 16 | 400 g (2 cups) | 960 ml (4 cups) | about 7 litres | two 5 litre jars |
Making a 1 Litre Batch
A 1 litre batch is a good first test. Use a 1.5 litre jar.
- Boil about 300 ml of water. Turn off the heat, add 2 tea bags and steep for 5 to 10 minutes for black tea, or 3 to 5 minutes for green. Remove the bags and stir in 50 g of sugar until it dissolves.
- Add about 580 ml of cold water to cool the mixture. Check that it is at room temperature, roughly 20 to 25 °C, before going further. Small batches cool quickly.
- Add 120 ml of starter, then the SCOBY with a little of its liquid.
- Cover the jar with a tightly woven cloth or coffee filter and a band. Follow the timing and taste checks in how to make kombucha at home, starting on day 7.
Making a 6 Litre Batch
A 6 litre batch is too much for most single jars, so split it across two 4 litre jars with about 3 litres in each. Make the sweet tea in one large pot, so each jar gets the same mix.
- Boil about 2 litres of water in a large pot. Turn off the heat, add 12 tea bags and steep as usual. Remove the bags and stir in 300 g of sugar until it dissolves.
- Add about 3.3 litres of cold water. This brings the sweet tea to about 5.3 litres.
- Cool the mixture to room temperature. A large pot takes longer to cool, so plan for a few hours. Standing the pot in a sink of cold water and stirring now and then speeds things up.
- Divide the sweet tea evenly between two clean 4 litre jars, about 2.6 litres in each. Add 360 ml of starter to each jar, then one SCOBY with some of its liquid.
- Cover both jars and ferment them as usual. Taste each jar separately from day 7, because they can differ.
How Much SCOBY Do You Need?
Plan on one SCOBY per vessel, with some of its liquid. A SCOBY grows to cover the surface of its vessel, so a SCOBY that roughly matches the size of the jar is a good fit. A small SCOBY is fine for a small batch. Healthy culture and enough starter liquid matter more than exact size. If you need another SCOBY, you can grow one from raw kombucha.
For a single large container, one SCOBY may take longer to cover the whole surface, and it is less common practice. Splitting into two or more jars, each with its own SCOBY, is usually easier to manage.
For a 5 gallon batch (about 19 litres), the 12% starter alone is about 2.3 litres. Most brewers split a batch that size across several vessels, each with its own SCOBY, rather than using one very large container. If you do want a single vessel, see brewing kombucha in a 5-gallon carboy.
Bottles per Batch
After you save about 12% of each batch as starter for the next one, you have roughly 0.88 litres of kombucha for every litre brewed. A 4 litre batch gives about seven 500 ml bottles. A 6 litre batch gives about ten or eleven.
How Batch Size Changes Timing
Batch size changes the timing less than room temperature does. The main differences are how long the sweet tea takes to cool, and whether each jar ends up with the same flavour. Taste from day 7 and check each jar separately.
Going Bigger: 5 Gallons and Beyond
Recipes for very large batches are tested less often than small ones. A continuous brew vessel is another way to keep a steady supply without one huge batch. The same ratios apply, but take more care:
- Check the acidity. Many guides suggest the mixed brew should test below about pH 4.5 at the start. pH test strips are the easiest way to check.
- Keep records for each vessel. Note the date, the room temperature, the starter amount and the first taste date.
- Taste more often in warm weather. Warm rooms speed up fermentation, so a batch can turn sharp sooner than expected.
- Keep each vessel clean. Wash and rinse every jar, pot and spoon before use.
FAQ
What is the ratio for kombucha?
Per litre of total batch: about 50 g of plain white sugar, 2 tea bags and 120 ml of starter, with the rest as sweet tea. For a 4 litre batch, that is 200 g (1 cup) of sugar, 8 tea bags and 2 cups of starter.
Can homemade kombucha be alcoholic?
Fermentation makes a small amount of alcohol in every batch, including commercial kombucha. Home batches can vary more than commercial ones, because conditions are harder to control. The safety guide explains what this means for drinking it.
How long does a batch take?
Usually 7 to 14 days at room temperature, depending on how warm the kitchen is. Start tasting on day 7.