How to Make Your Milk Kefir Fizzy

You made your milk kefir and it tastes great but you’d really love it to have some extra fizz? Well, worry not because you can easily make that happen!

To make your kefir fizzy, you need to do a second fermentation in a sealed container (in order to build up the carbonation).

Here’s how to do it.

1. Prepare for the second fermentation:

  • Pour the ready kefir into a clean glass bottle with a tight-fitting lid. Bottles designed for brewing, such as flip-top bottles, work best.
  • Optionally, add a small amount of sugar or fruit juice to the kefir. This provides additional food for the bacteria and yeast, which helps create more carbonation.

2. Seal and ferment:

  • Seal the bottle tightly.
  • Leave the bottle at room temperature for 12-24 hours.

3. Refrigerate:

  • Once the desired level of fizziness is achieved, refrigerate the bottle to slow down fermentation and carbonation. This also helps the kefir develop more flavor.


  • Pressure can build up quickly during the second fermentation. Make sure to check the pressure by opening the bottle carefully and move your kefir to the fridge as soon as it is as fizzy as you like it.
  • Experiment with timing: The duration of the second fermentation can vary based on room temperature and the desired level of fizziness. Start with 12 hours and adjust as needed.
  • If you’d like the kefir even fizzier, add some bakers yeast at the second fermentation step. Carbonation comes from yeasts eating sugar so increasing the content of both in the bottle during second fermentation would increase your chances of fizzy success.
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