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Second fermentation of water kefir

Second fermentation of water kefir is a process that adds more flavour and carbonation to the water kefir.

This is when you add new sugar or fruits/spices to a brew that has already been fermented and leave it to ferment for a second time in a sealed container.

During the second fermentation, water kefir becomes more flavourful, rich in carbon dioxide and some of the undesirable bacteria and yeast are eliminated.

How to second ferment water kefir?

First, strain the fermented water kefir from your grains.

Then pour kefir liquid into a sealable jar or bottle and add your desired combination of flavours including fruit juice or fruit, berries, spices and botanical extracts. Leave a few cm space at the top. For my second fermentation I use Kefirko jars.

Seal the lid and turn the jar a few times to mix. Leave to ferment at room temperature for another day. The second ferment enhances the fizziness and adds extra flavour to the brew.

There are many ways to flavour water kefir and you can get creative with what you use. Some ideas for flavour combinations: hibiscus, elderberries, strawberries, raspberries, blueberries, apples, grapes, pomegranates, coconut water, ginger, cinnamon, rosemary, mint, lavender, turmeric to name a few. Almost any fruit or fruit juice can be used to flavour water kefir.

This step is highly personalised as it depends on your own taste preferences. Don’t worry about getting it wrong, as you learn by experimenting. Think of this as small batch brewing and honing one’s craft as a brewer.

Recipes for the second fermentation

There are many different flavours that can be used for the second fermentation. Double fermented kefir water is then kept in the fridge and used within a few days.

Grapefruit flavour

Add 2 tablespoons of sugar to 1 l of fermented water kefir and mix completely to ensure that the sugar dissolves. Then add 150 ml grapefruit juice and keep in airtight bottles leaving it to ferment for about 24 hours at room temperature.

Berry flavour

Add 75 ml of blended or crushed berries and a tablespoon of lemon juice to 1 l of water kefir. Leave to ferment for 24 hours.

Ginger lemon

Squeeze 100 ml of lemon juice into 1 l of kefir water then add a tablespoon of grated ginger and 50 g of sugar. Leave to ferment for 24 hours.

Apple juice

Take the fermented water kefir and add apple juice then leave to ferment for about 24 hours.

Coconut water kefir

Add coconut water to the water kefir and leave to ferment for about 24 hours. This flavour cannot be used during the first fermentation as its antibacterial characteristics can lead to modification of the kefir grains culture.


Mango is also a flavour to be used during second fermentation. Add 100 ml of mango juice to 900 ml of water kefir that has undergone a first fermentation and leave to ferment for about 24 hours.


Add 100 ml of kiwi juice to 900 ml of water kefir, then leave to ferment for 24 hours.


Blend a handful of mint leaves, add them to 1 l of water kefir with 3 tablespoons of sugar. Blend the mixture and leave to ferment for 24 hours.

The second fermentation creates some amazing alterations to the taste and adds beneficial nutritional value. Experiment with your favourite seasonal fruits.

Do be careful when opening the bottle after the second fermentation. It may be super fizzy and could overflow so leave more space at the top of the bottles and also open the lid every so often to release the pressure.


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