Continuous brew (CB) kombucha is a set-up where one vessel with a spigot stays in use for months or years. You keep some mature kombucha and the SCOBY in the vessel, top it up with sweet tea, and draw off finished kombucha as you go. A continuous brew kit bundles the vessel with a culture and sometimes tea and sugar. In the UK, you can build the same set-up yourself, provided the spigot and vessel are food-safe and the room stays warm enough.
Short answer: continuous brewing suits someone who brews regularly and has a warm, steady spot for the vessel. It takes more effort to set up than a batch, but it can be less work once it’s running.
How continuous brewing differs from batch brewing
- Batch brewing: you brew a full vessel, ferment it, bottle it, clean up and start again. It’s simple and good for learning, but each batch needs a fresh start.
- Continuous brewing: you keep part of the brew and the SCOBY in the vessel, and refill as you draw off. You skip most of the cleaning and restarting. Many brewers like the steadier flavor this can give.
The trade-offs are real. A spigot vessel costs more than a jar. Each draw is less predictable, so it’s harder to time each batch exactly. The set-up also needs a stable, warm spot, and a neglected vessel can take time to recover.
What a continuous brew set-up needs
- A vessel with a food-safe spigot. Porcelain, glass, stainless steel, or an oak barrel with a lead-free spigot are the materials one widely used guide recommends. Avoid plastic or metal taps, except 316 stainless steel. Check the spigot as carefully as the vessel.
- A cloth cover secured with a rubber band. See what to cover your kombucha with.
- Sweet tea. About 1 cup of sugar per US gallon (roughly 50 g per litre) and 4 to 6 tea bags per gallon is a common ratio. Use a plain base tea.
- A stable warm spot. One widely used guide suggests 24 to 29 °C (75 to 85 °F), out of direct sun. Other guides give a lower range. Do you need a heating pad for kombucha? covers the options if your room runs cold.
- Mature kombucha and a SCOBY to start, from a friend’s brew, a culture kit, or one you grow yourself.
- Optional: pH strips or a pH meter. One guide suggests a target of pH 2.8 to 3.2 for continuous brewing.
Buying a continuous brew kit in the UK
Check these before you buy:
- Spigot material. It must be food-safe. Ask the seller if the listing doesn’t say.
- Vessel size and weight. A full vessel is heavy and breakable. Make sure it fits the space you have and that you can lift it safely.
- What’s included. The culture (and whether it’s live), tea, sugar, cover and instructions.
- Shipping and breakage cover. Glass and ceramic are heavy and can break in transit. Check the delivery terms and the returns policy.
- Heater compatibility. UK mains supply is 230 V. Check the plug and voltage of any heat mat or wrap, and use a thermostat controller with it.
Setting up the vessel
- Clean and rinse thoroughly. Rinse off any soap or cleaning residue before the tea goes in.
- Brew a first batch. Fill the vessel with cooled sweet tea, then add the SCOBY and starter liquid. Ferment until the brew tastes right. One guide says the first batch can take 2 to 4 weeks.
- Draw off and refill. Once the first batch is established, draw off roughly a quarter to a third of the vessel. Refill with the same volume of cooled sweet tea. Keep the refill below about a third at a time so the culture stays balanced.
- Wait, then taste. Subsequent batches can be ready in 5 to 7 days, according to the same guide. Taste the brew before each draw. If it’s too sweet, it isn’t ready. If it’s tangy and balanced, it is.
- Repeat. Keep drawing and refilling on a regular schedule.
Keeping the culture healthy
- Keep it warm, not hot, and out of direct sun.
- Keep the cover on, and check it at each refill. Flies can get in through any gap.
- Watch for mold. Fuzzy green, blue, gray, black or brown growth means you should discard the SCOBY and the brew, and wash the vessel. Dark spots and strands are usually normal, as the yeast dies back.
- Remove yeast buildup when it becomes thick. One guide suggests checking the SCOBY every few months.
- Do a full clean only when needed. One guide suggests every 6 to 12 months.
Bottling from a continuous brew
Draw off into swing-top bottles, add any flavoring at bottling, seal them, and leave them to carbonate for a few days before refrigerating. Most guides advise keeping the base tea plain and adding flavors at bottling. Fruit and juice add sugar, which raises pressure, so keep additions modest. See best bottles for kombucha for bottle choice and safety.
When continuous brewing is not a good fit
- You want a different tea or flavor every batch. Continuous brewing works best with one plain base.
- Your room is cold for long stretches. You’ll need reliable heat, which adds cost and effort.
- You’re away for long periods. Nobody is there to draw and refill, so plan ahead, or ask someone to check in.
- You’d rather brew one large batch. A batch in a single large vessel may suit you better. See brewing kombucha in a 5-gallon carboy.