How to Make Kombucha at Home: A Step-by-Step Recipe

Making kombucha at home takes a few simple ingredients, a clean glass jar and some patience. Most batches take about 7 to 14 days to reach a flavour you like, and then a few days in sealed bottles if you want it fizzy. This guide gives you a recipe for 4 litres, shows you how to tell when it is ready, and explains how to bottle it with less risk of gushing or bottle pressure problems.

The method is the same at any size. If you want to scale up or down, see how batch size changes the recipe.

What You Need

Ingredients for a 4 litre batch

• About 3.5 litres of filtered or dechlorinated water (see “Choosing Tea, Sugar and Water” below)
• 200 g (1 cup) plain white sugar
• 8 black or green tea bags, or about 2 tablespoons of loose-leaf tea
• 500 ml (2 cups) of starter kombucha, unflavoured and unpasteurised, from a previous batch or a raw store-bought kombucha
• 1 SCOBY (the rubbery culture), with some of its liquid. No SCOBY yet? See how to grow a SCOBY.

Equipment

• A wide-mouth glass jar of about 5 litres (1.5 gallons). A 4 litre brew needs room at the top, so a 4 litre jar is too small.
• A large heatproof pot
• A clean wooden, plastic or stainless steel spoon
• A funnel and a measuring jug
• A tightly woven cloth or two coffee filters, and a rubber band
• Bottles made for fizzy drinks: flip-top glass or PET plastic. Keep one small plastic bottle from the same batch to test the fizz by squeezing.
• Optional: a thermometer for checking the temperature, and pH test strips

Recipe for 4 Litres

1. Clean everything. Wash the jar, pot, spoon, funnel and jug in hot water with plain dish soap, then rinse well. Skip bleach and scented cleaners, as residue can harm the culture. Wash your hands, and take off rings and watches before you touch the SCOBY.

2. Make the sweet tea. Bring about 1 litre of the water to the boil. Turn off the heat, add the tea bags and steep for 5 to 10 minutes for black tea, or 3 to 5 minutes for green tea. Lift the bags out without squeezing them, as squeezing can make the brew bitter. Stir in the sugar until it has fully dissolved.

3. Cool it down. Pour the sweet tea into the jar and top it up with the remaining cold water, about 2.5 litres. The mixture needs to reach room temperature, roughly 20 to 25 °C (68 to 77 °F), before the SCOBY goes in. Hot liquid can damage the SCOBY. A thermometer makes this easier to judge.

4. Add the starter, then the SCOBY. Stir in the 500 ml of starter. Lower the SCOBY in with clean hands. It may float, sink or sit sideways, and all of these positions are normal. Leave about 5 cm (2 inches) of space at the top of the jar.

5. Cover and rest. Cover the jar with the tightly woven cloth or coffee filters and secure it with the rubber band. Choose a steady spot out of direct sunlight, away from heaters and fruit bowls. The jar needs airflow, so don’t shut it in a closed cupboard. Once it is settled, leave it alone.

6. Taste from day 7. After a week, slide a clean straw down the side of the jar, past the SCOBY, and taste the liquid. Keep tasting every day or two until the flavour suits you.

Temperature and Timing

Temperature changes the timing more than anything else. Most kitchens fall in a comfortable range of about 20 to 27 °C (68 to 80 °F).

These are rough guides, not fixed timings. If your kitchen runs cold, see whether you need a heating pad. A stick-on thermometer on the side of the jar shows the actual temperature of the brew, which can differ from the room.

A new layer of SCOBY often forms on the surface over the first week or two. Brown or black strands hanging below the surface are normal too. Neither is a sign that something has gone wrong.

Tasting and Deciding When It Is Ready

There is no single correct day to bottle. Kombucha becomes more sour the longer it ferments, and the sugar keeps being used up. Use your taste to decide:

• Still sweet: leave it a few more days, then taste again.
• Balanced: tart, with a little sweetness left. This is the usual point to bottle or chill.
• Sharp or vinegary: the batch has fermented long or warm. A clean-smelling, mould-free batch is usually still safe to drink, but bottle earlier next time. Why kombucha turns too vinegary covers the causes and fixes.

Once the flavour is right, don’t leave the jar out. Kombucha keeps changing at room temperature.

Save Your SCOBY and Starter

Before you bottle, set aside the SCOBY with about 500 ml (2 cups) of finished kombucha taken from the top of the jar. Store it in a clean jar with a cloth cover, at room temperature, to use as starter for your next batch. You can also keep spare SCOBYs in a SCOBY hotel, which is a jar of kombucha that keeps them covered and ready.

Then pour the rest through a clean funnel into bottles or a jug. Wash the jar before adding the next batch of sweet tea.

Second Ferment: Flavour and Fizz

The second ferment is optional, but it is how most brewers get both fizz and flavour. The second fermentation guide covers flavours in more depth. Sugar in the sealed bottle feeds the yeast, which makes carbon dioxide.

• Add flavour. For a 500 ml bottle, start with about 2 tablespoons of fruit juice, such as apple, grape or cherry. You can also use a small handful of chopped or mashed fruit, such as berries, pineapple or mango, or a few slices of fresh ginger. Start small. You can always add more next time.
• Leave headspace. Fill each bottle to about 2.5 cm (1 inch) below the top, and seal it tightly.
• Wait at room temperature. Leave the sealed bottles out of direct sunlight for about 1 to 4 days. A cooler kitchen takes longer.
• Check the fizz. Squeeze the small plastic bottle each day. When it feels firm, the glass bottles usually have enough fizz. The plastic bottle is the best guide, because glass hides how much pressure is building.
• Chill before opening. Move the bottles to the fridge when they are fizzy enough, and chill them before opening. Cold liquid holds the bubbles and gushes less.

Bottling Safely

Pressure builds in sealed bottles, and it can be strong. These habits help:

• Use the right bottles. Round flip-top glass bottles and PET plastic bottles are the usual choices. Avoid square or decorative bottles, and throw out any bottle with a chip or crack.
• Be careful with sweet batches. A batch that is still very sweet, or has lots of fruit or juice added, can build pressure quickly.
• Check every day. Many brewers loosen the cap of each bottle briefly once a day to let out some gas. This is often called burping. If you can’t check the bottles daily, don’t leave them out at room temperature.
• Open them carefully. Open cold bottles slowly, over the sink, with the bottle pointing away from your face.

Choosing Tea, Sugar and Water

Tea. Black tea is the traditional choice, and green tea works well too. White and oolong teas also work. Use plain tea with no added flavour or oil. Earl Grey, which is flavoured with bergamot oil, and flavoured or fruit blends can cause problems. Stick with plain black or green tea for your first few batches, and see the best tea for kombucha when you want to branch out.

Sugar. Use plain white cane sugar. Honey, stevia, artificial sweeteners and other sugar substitutes don’t feed the culture in the same way, and they are not standard for kombucha. Honey is used for a separate drink called jun.

Water. Use filtered water, or tap water that has been boiled and cooled, or left out overnight so the chlorine can escape. Chloramine, which some water supplies use instead of chlorine, does not escape overnight. If your supply uses chloramine, a filter that removes it is the better choice. Check with your local water supplier if you are not sure.

Containers and Cleanliness

Glass is the safest default for the brewing jar. It does not react with the acidic brew.

Food-grade stainless steel is also widely used for larger vessels. Avoid lead-glazed ceramics, crystal, unlined copper, aluminium and galvanised metal, because acidic liquids can take up metals from them. Plastic works well for bottles, but many brewers prefer glass or stainless for the first ferment.

Clean and rinse thoroughly every time. A clean setup, the right amount of starter and a mould-free batch matter more than any single product.

Quick Troubleshooting

• No new SCOBY layer. A cool room, a weak starter or a small SCOBY can all slow things down. Give it a few more days and check the temperature.
• Mould. Fuzzy or dry spots in blue, green, black or white mean the batch should be thrown out, including the SCOBY and liquid. Don’t skim it off and carry on. If you’re not sure, compare it with mould versus a healthy SCOBY.
• A thin, wrinkled white film. This is usually kahm yeast, which is not fuzzy mould. Many guides still advise starting again, with stronger starter and a little more warmth.
• Flat. Usually there is not enough sugar left for the second ferment, the bottles have too much headspace, the caps leak, or the room is cold. Give it another day or two, or see why kombucha goes flat.
• Gushing when opened. Often there is too much sugar or fruit, the bottles were too warm, or they were opened before they were chilled. Chill them longer and use less juice next time.
• Vinegary. The batch fermented too long or too warm. See why kombucha turns too vinegary.
• Fruit flies. Use a tightly woven cloth or a coffee filter held firmly with a band. Loose cheesecloth lets them in.

Safety Basics

Home-brewed kombucha is widely made, but it is a live ferment, so a few things matter most: a clean setup, glass or stainless vessels, enough starter to keep the brew acidic, and throwing out any batch with mould. Kombucha is acidic, which makes botulism unlikely in a well-brewed batch. The bigger everyday risks are mould and contamination, so hygiene and mould checks matter most.

For a fuller look at risks, read is homemade kombucha safe to drink. If you are pregnant or breastfeeding, are giving it to a child, or have a health condition, check with a doctor or other health professional before you drink it. This is general information, not medical advice.

Where to Go Next

• Kombucha batch sizes, for 1 litre, 3 litres, 6 litres and beyond
• How much sugar for 1 litre of kombucha
• Can you start a SCOBY from scratch?
• Kombucha explained: the fermented sweet tea drink
• Why is my kombucha too vinegary?