How to Brew Kombucha

Everything you need to wake up your SCOBY, brew your first batch and keep your culture happy for years. Read it through once before you start, then keep it handy for brew day.

Before you begin

When your SCOBY arrives

Keep it somewhere cool and out of direct sunlight, still in its bag with its starter tea. Never put it in the fridge. If it arrives on a cold winter's day, leave it at room temperature for 48 hours to warm up before its first brew.

Wash your jar and utensils well in hot soapy water and rinse thoroughly. There's no need to sterilise. Never pour boiling water into glass.

What you'll need

• Your kombucha SCOBY and the starter tea it came in
• A glass jar, a little bigger than the amount you're brewing
• Real tea: black, green or white (tea bags or loose)
• Granulated white sugar
• A cotton or muslin cloth and an elastic band
• A plastic or wooden spoon

How much to use

Brew the size your SCOBY is made for. A small SCOBY in a big batch can't sour the tea fast enough, and that's when mould gets a chance.

Don't cut the sugar. The SCOBY eats it, so the finished drink is far less sweet than the tea you start with. Going below the lower amount weakens the culture. Using loose tea? About 2g is the same as one tea bag.

Batch brewing, step by step

This is the classic method: brew a jar, bottle it, start again. Quantities below are for a 2 litre brew. Use the table for other sizes.

1. Make the sweet tea

   Put 6–8 tea bags and 160–200g sugar in a heatproof jug or pan, pour over 2 litres of boiling water and stir. Leave for 30 minutes, take out the tea bags, then let it cool completely. It's ready when it feels barely warm on your little finger. Cold is even better.

2. Add your SCOBY

   Pour the cool tea into your jar. Add your SCOBY, lighter side up if you can tell (don't worry if you can't), and all the starter tea from its bag. It might float, sink or sit sideways. All of these are fine.

3. Cover and leave it somewhere steady

   Cover the jar with your cloth and secure it with the elastic band. Keep it out of direct sunlight at a steady room temperature, ideally 20–23°C, off the floor and away from busy spots.

4. Taste from day 3

   In a typical UK home, brewing takes 5–18 days. Kombucha can take anywhere from 7 to 30 days though, depending on temperature, so a cool room will slow it down. From day 3, sip a little each day using a straw or spoon. It's ready when it tastes fruity and tart rather than like sweet tea. The longer it brews, the less sweet and more sour it gets.

5. Bottle it, and keep some back

   Pour off your kombucha, leaving the SCOBY and some of the brew in the jar to start your next batch: 10% of the brew or 125ml, whichever is more (so 125ml from a 1 litre batch, or 200ml from 2 litres). Chill your kombucha for a few hours before drinking. The longer it's chilled, the fizzier it gets.

It should smell a little vinegary and yeasty, a bit like apple cider vinegar.

Continuous brewing

With a continuous kit, you draw kombucha from the tap whenever you want some and top it up with fresh sweet tea. You still bottle it, you just pour from the tap instead of emptying the jar. Not sure which method suits you? Try our batch or continuous quiz.

1. Check the tap first

   The nut on the back of the tap can work loose in the post. Tighten it, fill the vessel with water to check for leaks, then empty it. Check the nut now and then, especially if you move the vessel.

2. Make your first sweet tea

   Use 4 litres of water, 12 tea bags and 320–400g sugar, exactly as in the batch method, and let it cool completely. Don't pour boiling water into a glass vessel.

3. Set it up where it will live

   A full vessel is heavy, so put it in place first: a steady room temperature and out of direct sunlight. Close the tap, pour in the cool tea, then add your SCOBYs and all their starter tea. Cover with a cloth and an elastic band.

4. Wait for the first brew

   A bigger volume takes longer, usually 10–18 days. Start tasting from the tap after about 10 days. It's ready when it's fruity and tart.

5. Draw off and top up

   Draw off about a litre at a time, then pour back the same amount of cooled sweet tea. Leave it at least 24 hours before drawing more. Early on, it can take 3–5 days to be ready again, but it speeds up as your SCOBYs grow.

Growing your brew: as your SCOBYs grow, add a little more tea than you take out, for example 1.5 litres back for each litre drawn off, then wait 3–5 days. With a large vessel, build up the volume slowly. Too much tea for too little SCOBY is the most common cause of mould.

Looking after a continuous vessel

• Trim the SCOBY. If it fills the vessel or the brew turns sour too fast, cut the SCOBY into quarters with a plastic knife and remove one piece. You'll need to do this more often in summer.
• Deep clean every 12–18 months. Keep your SCOBYs in some of their own brew, empty and wash the vessel, and check the tap's rubber seal, which kombucha's acidity can wear down.
• Change the cloth regularly to keep fruit flies and dust out.

Dehydrated SCOBY

A dried SCOBY travels and keeps well, but it needs waking up before it can brew. Activation takes about 30 days. After that, it brews just like a fresh SCOBY.

Got a dehydrated SCOBY? Download the full activation guide (PDF) for every step, what to expect and troubleshooting.

At a glance

Keep everything at 20–25°C. Below 20°C the brew can fail and is more likely to go mouldy, so a heat tray helps in a cold home. You'll also need distilled white vinegar, a 1 litre and a 1.5 litre glass jar, and a thermometer.

Activating your SCOBY

1. Make a small sweet tea

   Put 40–55g sugar and 2 tea bags in a heatproof jug or pan and pour over 500ml of just-boiled water. Stir until the sugar dissolves, leave it for 8–15 minutes, then take out the tea bags.

2. Cool it right down

   Let it cool below 20°C. Check with a thermometer, as warm tea can harm the culture.

3. Add vinegar and your SCOBY

   Pour the cooled tea into your smaller jar, add 100–115ml white vinegar, then add your dried SCOBY.

4. Cover and leave it for 30 days

   Dampen the cloth with a little vinegar, cover the jar and secure it with an elastic band. Leave it at 20–25°C, out of direct sunlight, for at least 30 days, and try not to move or prod it. Dab a little vinegar on the cloth every day to help keep mould away.

What to expect: it's normal to see no change at all. The activation batch will be far too sour to drink. That's fine, as it's the starter for your first real batch. Green, brown or black fluffy bits hanging in the brew are yeast, not mould.

Your first drinkable batch

1. Make 1 litre of sweet tea

   Use 80–110g sugar and 3–4 tea bags, and let it cool below 20°C.

2. Add everything from the activation jar

   Pour the cooled tea into your larger jar and add the SCOBY and all of its liquid.

3. Cover and brew for 7–18 days

   Keep it at 20–25°C, out of direct sunlight. From about day 3, taste a little each day. It's ready when it tastes fruity and tart rather than like tea.

After that, keep about a third of each brew as starter for the next one, and stick to 1 litre batches until your SCOBY has grown. Then you can move up to the bigger batches in the batch brewing section.

Looking after your SCOBY

Babies

Each brew grows a new layer on top: a baby SCOBY. Lift it off when you bottle and keep it with the mother. It's fine if they stay stuck together. Once a baby is about 1–2cm thick, it can brew a batch of its own or go to a friend.

Taking a break

Always keep your SCOBY covered in sweet tea or its own kombucha. Never let it dry out. If you're not starting a new brew straight away, cover the jar and keep it at room temperature. It can rest like this for up to 4 weeks, depending on how warm it is. Check it regularly and top it up with sweet tea so it never dries out.

Grow slowly. Start with the size your SCOBY came for and increase as it thickens. It's the simplest way to avoid mould.

Is it mould?

Mould is rare with a healthy SCOBY and clean kit, but new brewers often worry about it. Here's the quick check: where is it?

Think it's mould? First compare it with the photos in our mould or yeast photo guide.

Bought the culture from us recently and want a replacement? Don't throw it away. Cover the brew, don't drink it, and send us a photo so we can see it and help. We can't replace cultures that have already been thrown away.

Otherwise, if it's mould, throw away the brew and the culture, wash everything in hot soapy water and start again.

Keeping mould away

• Stick to the sugar amounts, and never brew more than your SCOBY is sized for.
• Cover with a breathable cloth, not an airtight lid.
• Keep the jar away from other ferments, fruit bowls, bread and houseplants.
• Rinse equipment well so there's no soap left behind.
• Keep your SCOBY covered in liquid at all times.

Bottling and fizz

Kombucha is naturally sparkling, and sealed bottles can build up a lot of pressure, especially in warm weather.

• Chill bottles well before opening, and open them slowly over the sink.
• Burp sealed bottles every day or so: ease the lid until it hisses, then close it again.
• Keep bottles somewhere cool.

Stored in glass, kombucha keeps for up to 2 years. Once opened, drink it within about 10 days. Over time it slowly turns into kombucha vinegar, which is lovely in salad dressings and marinades, and makes a good natural cleaner.

Raw kombucha often has little floating bits. They're harmless, but you can strain them out with a plastic sieve if you prefer.

Want more fizz? See our guide to getting fizz: the best bottles, how much sugar to add, why it might be flat, and how to stop it gushing.

Frequently asked questions

Does my SCOBY come with starter tea?

Yes. Your SCOBY arrives in its pouch with its own starter tea. Add all of it to your first brew.

How long will my SCOBY last in its pouch?

Anywhere from 1 to 12 months. Keep it somewhere cool and out of direct sunlight, still in its pouch, but never in the fridge.

My pouch has puffed up. Is that OK?

Yes, it's actually a good sign. Live cultures don't have an off switch, so your SCOBY keeps fermenting on its way to you. That traps the fizz in the pouch and makes it puff up like a pillow. It means your SCOBY is raring to go.

My pouch has leaked. Is my SCOBY OK?

It's very rare, but with any liquid in the post we can't rule it out. It's usually just a few drops of kombucha, even if it looks worse. If the pouch still has most of its starter tea, your SCOBY will be fine. If the pouch is empty, get in touch and we'll replace it.

It arrived on a cold day. Is it OK?

Yes. Leave it at room temperature for 48 hours to warm up before its first brew.

Does kombucha contain alcohol?

Alcohol is a natural byproduct of all fermentation, including kombucha, but it's generally less than 2%. For children and anyone sensitive to alcohol, we recommend diluting it with spring water to reduce the alcohol.

Is kombucha halal?

Many Islamic scholars consider kombucha halal, because the tiny amount of alcohol (usually under 0.5%) is made naturally during fermentation and isn't enough to intoxicate, in the same way as vinegar or bread. Some are more cautious about home-brewed kombucha, as the alcohol level can vary, and stronger "hard" kombucha isn't considered halal. Our cultures and kits aren't halal certified, so if you're unsure, please check with your imam or a scholar you trust. A shorter second ferment and chilling your bottles promptly helps keep the alcohol low.

Is kombucha kosher?

The basic ingredients, tea, sugar and the culture, contain no meat or dairy. However, our cultures and kits aren't kosher certified, and some kosher authorities advise buying certified kombucha rather than brewing your own. If keeping kosher is important to you, please check with your rabbi or kosher authority.

Which tea can I use?

Real tea: black, green or white, as tea bags or loose. Avoid flavoured or scented teas.

Can I use less sugar?

No. The SCOBY eats the sugar, so the finished drink is far less sweet than the tea you start with. Using less weakens the culture and makes mould more likely.

Can I use honey, coconut sugar or sweeteners?

We don't recommend them. The whiter the sugar, the cleaner and crisper the taste, so white or organic cane sugar gives the most reliable brew. Darker and alternative sugars are very mineralised, which kombucha doesn't really like, and honey is for Jun. Find out more in our guide to sugars in fermentation. You can add a sweetener to flavour your kombucha once it's brewed, just never for the actual ferment. Find out why kombucha needs real sugar.

How long does a brew take?

In a typical UK home, 5 to 18 days. It can take anywhere from 7 to 30 days depending on temperature, so a cool room will slow it down.

Does my SCOBY need to float?

No. Floating, sinking or sitting sideways are all normal and don't affect the brew.

What if I go on holiday?

Your SCOBY can rest in its jar for up to 4 weeks, depending on how warm it is. Keep it covered in sweet tea or its own kombucha and never let it dry out. See looking after your SCOBY.

How long will my SCOBY last?

Looked after well, for a lifetime. It grows a new baby SCOBY with every brew.

Do I need to sterilise my equipment?

No. Wash everything well in hot soapy water and rinse thoroughly so there's no soap left behind.