How to Store Kombucha, and Why It Sometimes Fizzes Over

Raw kombucha is a living drink, and living things have opinions about how they're kept. Most of the questions we get after someone's first order come down to storage: why did it fizz over, why is there stuff floating in it, how long does it keep. Here are the answers, from people who've been bottling the stuff since 2015.

Keep it in the fridge. Always.

This is the whole rule. rok is raw and unpasteurised, which means the cultures are still active in the bottle. Cold slows them right down. Warm wakes them up, and a woken-up kombucha keeps fermenting: it gets more sour, more fizzy and slowly eats whatever sugar is left. A few hours on the bench for a party is fine. A week in a hot car is not.

The Waves & Caves sodas, mixers and sparkling waters are different. They're not fermented, so they're happy in the pantry until you want them cold.

Why it sometimes fizzes up when you open it

Because it's alive. The yeast in the culture makes carbon dioxide, and if the bottle has warmed up at any point, it will have made a bit more. That's not a fault, it's the same process that carbonated it in the first place. To avoid a fountain:

• Make sure it's properly cold before opening. Cold liquid holds fizz better.
• Don't shake it. Ever. Tip it gently upside down once if you want to mix the sediment back in.
• Open it over the sink the first time, especially if it's been in transit.
• Crack the cap slowly and let it hiss before you take it right off.

The floaty bits are supposed to be there

Raw kombucha has sediment. Sometimes it's a fine layer at the bottom, sometimes it's stringy strands, sometimes a small jelly-like disc forms at the top. All of it is the culture, the same yeast and bacteria that made the drink. It's harmless, and plenty of people consider it the best bit. If it puts you off, pour gently and leave the last bit in the bottle. If you see fuzzy mould (green, black, dry-looking) that's a different story and it should be thrown out, but that's rare and it doesn't look anything like the normal strands.

How long does it keep?

There's a best before date on every bottle and we mean it, but it's a taste guide, not a safety cliff. In the fridge, unopened, rok is at its best up to that date and drinkable a while past it, getting a bit more sour each week. Once opened, put the cap back on and drink it within a couple of days. It won't go off in the way milk does, it just goes flat and sharper.

Can you freeze it?

You can, but you'll kill the cultures and lose the fizz, so what you get back is a flat, tangy tea. Fine for ice blocks in summer, not the same drink. If you want to freeze something, freeze the sodas.

Travelling with it

Esky with ice, bottles upright, and open them cold. Kombucha that's been rolling around warm in a boot all afternoon is the one that fountains. We pack orders with that in mind, but once it's yours, keep it cold and upright and it'll behave.

Getting the most out of a bottle

Serve it cold, in a glass, over ice if you like. It's better than drinking from the bottle because you can see the colour and smell it properly. If it's slightly more sour than you expected, that's usually a bottle that has had a warm patch somewhere. A squeeze of lime or a splash of sparkling water softens it right up, and our mocktail recipes are built on exactly that.

Still got a question? Reply to any of our emails or use the contact page. A real person reads it, and if something arrived in a state it shouldn't have, we'll sort it out.