Bottling & second fermentation

Make your kombucha sparkle

Your kombucha is ready: fresh, lightly tangy, and already delicious on its own. But this is where you can choose to go a step further. A second fermentation in the bottle turns your kombucha into a bright, sparkling drink — the moment it truly becomes lively and full of character.

What is bottling?

Bottling is simply moving your kombucha into airtight bottles. That’s where the magic of carbonation happens. In the sealed bottle, the yeasts use the last traces of sugar to produce carbon dioxide (CO₂). Since the gas can’t escape, it dissolves into the drink and creates the natural fizz that makes sodas so irresistible.

What bottles can you use?

You have two main options:

  • Flip-top bottles – They look great and can be reused endlessly. We do recommend “burping” them every few days to release built-up pressure. It’s also an easy way to check if your kombucha is already becoming fizzy. The drawback: flip-top bottles seal so tightly that, under high pressure, the glass can crack or even explode. We’ve heard stories of bottles literally blowing apart.
  • Crown-cap bottles – Our favourite. In our experience, these are the safest option: if too much pressure builds, the cap simply pops off. No glass shards — just bubbles. Using a small hand capper, you can easily seal crown-cap bottles at home. There are basic, budget-friendly models and some that are a bit more ergonomic — both work great. It’s simply a matter of preference.

Probiotics and second fermentation

One of the most common questions: does the second fermentation create more probiotics? The short answer is no. Bottling doesn’t meaningfully increase the number of microorganisms. The second fermentation mainly affects flavor, aroma, and carbonation — not the amount of live cultures or bioactive compounds.
In other words: your kombucha is just as microbiologically rich after the first fermentation as after the second. Want to know what is happening inside your brew? Read this article.

Basic recipe

  1. Brew the base

    • Mix your kombucha starter with fresh, cold tea.

    • Ratio: 1:3 for a tangier kombucha, 1:5 for a milder one.

    • The type of tea has a huge influence on your final flavor — don’t be afraid to experiment. Need inspiration? Try a 50/50 blend of rooibos and green tea.

  2. Add sugar

    • Dissolve your bottling sugar in the cold tea.

    • With beer, brewers often use 6–10 g of sugar per liter, which is also a good starting point for kombucha.

    • Is your starter still a bit sweet? Then choose the lower end (around
      6 g).

  3. Bottle

    • Fill your bottles up to 2–3 cm below the rim.
      Seal with crown caps or flip-tops (remember to burp flip-tops regularly!).

  4. Ferment

    • Leave the bottles at room temperature for 1–2 weeks.

    • After the first week, you can open a bottle now and then to check whether you’re happy with the level of carbonation.

  5. Chill

    • Once you’re satisfied, move the bottles to the fridge.

    • This doesn’t completely stop fermentation, but it slows it down significantly.

Find your flavors!

Your second fermentation is the perfect moment to experiment with bold flavors and aromas.
Keep in mind: the microorganisms love these ingredients, so flavors can become surprisingly intense or funky. It’s best to use dried ingredients — they’re more stable and reduce the risk of unwanted off-flavors.

  • Ginger – fresh, spicy and always a crowd-pleaser.
  • Dried fruit – such as apricot, fig or raisin.
  • Herbs & spices – think cinnamon, mint, basil or lavender for your own twist.
  • Tea variations – never underestimate the power of the tea itself: a rich green tea, smoky lapsang or fragrant jasmine can give your kombucha that extra character.

In short: experiment freely, but keep it simple. Often, one well-chosen ingredient is enough to lift your kombucha to the next level.

Discovered a killer flavor combo? Show us on Instagram —  @BiomeBrew!

#BrewYourBiome