After completing the first fermentation (F1) of your kombucha, you’re now ready to move on to the exciting part: second fermentation (F2)! This is where you’ll flavour your kombucha and bottle it to create carbonation. In this guide, we’ll walk through the steps of F2, flavouring ideas, bottling tips, and how to make sure your kombucha turns out perfectly fizzy. 

What is Second Fermentation (F2)? 

Second fermentation is the stage where you flavour your kombucha and seal it in a bottle, trapping carbonation inside. This process typically takes 2-4 days at room temperature but can vary depending on your ingredients and environment. 

Just like in beer or champagne making, adding sugar (usually from fruit) provides fuel for the yeast. As the yeast consumes the sugar, it produces carbon dioxide, which gives kombucha its characteristic fizz. 

Step-by-Step Guide to Second Fermentation 

1. Flavouring Your Kombucha 

  • Add ¼ – ⅓ cup of pureed or juiced fruit into each 16 oz. bottle of kombucha. For a 1-gallon batch, this usually yields around 7 bottles. 

2. Remove the SCOBY and Starter Tea 

  • Carefully remove the SCOBY and 2 cups of kombucha from your brewing vessel. Set this aside for your next batch. You can store it in a SCOBY hotel or a clean bowl if you plan to use it right away. 

3. Stir the Kombucha 

  • Before bottling, stir the remaining kombucha in the brewing vessel to evenly distribute the yeast and bacteria. This will ensure consistent carbonation across all your bottles. 

4. Bottle the Kombucha 

  • Use a pitcher and funnel to pour your kombucha into bottles, leaving ½ – 1 inch of headspace at the top of each bottle. 

5. Dry the Tops of the Bottles 

  • Wipe down the tops of your bottles to ensure the lids are dry. This helps create a tighter seal. 

6. Seal Tightly 

  • Seal the bottles as tightly as possible. If you’re using screw-on lids, consider using rubber grippers to ensure a secure seal. 

7. Let the Bottles Ferment at Room Temperature 

  • Let your bottles ferment for another 2-3 days at room temperature. A dark cupboard works well. There’s a slight risk of over-carbonation or bottle explosions, so store them in a closed cabinet to contain any potential mess. 

Note: If you’re using thin glass beer bottles, don’t let them sit at room temperature for more than a day. Move them to the fridge after 24 hours to avoid glass breakage. 

8. Move to the Fridge 

  • After 2-3 days, transfer the bottles to the fridge. Chilling them will pause fermentation and help retain the carbonation. Once they’re cold, open a bottle to test for fizz. 

 

Should You “Burp” Your Bottles? 

Some brewers recommend “burping” (opening the bottles slightly to release excess gas) during second fermentation. However, this isn’t necessary, and it can be counterproductive to building up carbonation. Instead, just leave the bottles undisturbed for 2-3 days and chill them afterward. Once cold, test for carbonation. 

Troubleshooting Carbonation 

If your kombucha isn’t as fizzy as you’d like, don’t worry. You can bring the bottles back to room temperature for another day or two and then test again. Each brew is different, and carbonation levels depend on several factors, including the type of fruit, temperature, and bottle type. 

  • Some flavours may take longer to carbonate (up to a week), while others will be fizzy within just a few days. Patience and experimentation are key. 

Conclusion 

Second fermentation is where your kombucha gets its flavour and fizz, transforming it from a tangy tea into a bubbly, flavourful beverage. By experimenting with different fruits and flavour combinations, you can create unique and delicious kombucha every time. Whether it takes 2 days or a week to reach the right level of carbonation, you’ll quickly get a feel for what works best in your brewing environment. 

Enjoy the process and have fun customising your kombucha!