
What is Kefir Soda?
As we covered in my previous post, Making Your Own Water Kefir, water kefir is a fermented beverage combining sugar, water, and kefir grains. The resulting drink is full of gut-healthy microbes, not to mention it’s super tasty!
I love plain old-fashioned water kefir, but with one more step, we can have something even better- effervescent and richly flavored kefir soda!
To go from plain kefir to kefir soda requires just one additional step – the second fermentation. This step involves adding a tiny bit more sugar, along with fresh juice, to your finished kefir. This blend is then put into a ferment-safe bottle with a lid.
The living cultures in the water kefir will consume that additional sugar and release carbon dioxide, thus creating bubbles when put into a sealed container.
Flavor Combinations

There are endless possibilities when it comes to flavoring your kefir soda. For this recipe, I will be making kefir soda with watermelon, cucumber, and mint.
Here are some of my other favorite flavor combinations:
- Cranberry, orange, cinnamon
- Apple, strawberry, chia seeds
- Orange, ginger, cayenne
- Blueberry, raspberry, vanilla
- Blueberry, lavender
- Peach, jalapeño, lime (pictured above)
If flavored kefir soda isn’t your thing, you can simply add your additional sugar and it will still ferment to make a plain kefir soda.
Keep in mind that these flavors can all be added to taste, there are no wrong answers here!
Ingredients & Equipment

For this recipe, we will be picking up where we left off from Making Your Own Water Kefir. Assuming you have finished kefir, you only need a couple of additional ingredients and equipment to turn it into kefir soda.
Sugar
Adding a tiny bit more sugar to your water kefir will give the yeast something to eat, creating bubbles when placed in a sealed container.
Flavor Additions
Fresh fruit, dried fruit, vegetables, herbs, and spices can all be used to flavor kefir soda. We will be blending several fresh fruits and herbs for this recipe and straining them into our bottle.
Ferment-Safe Bottle with Lid

Placing our kefir, juice, and sugar into a bottle with a lid, will create the pressure needed to create bubbles. Please make sure whatever bottle you use can handle the added pressure – otherwise, you’re likely to have a big mess!
Examples of fermenting bottles include flip-top glass bottles, wine bottles with cork, mason jars, or fido jars.
Cheesecloth or Strainer
This will be used to strain our juice to remove solids before adding it to our bottle with the kefir. Nut milk bags will also work great.
Blender
This will be used to juice our fresh fruits, then strained to remove any solids. A food processor or juicer will also work.
How to Make Water Kefir Soda
Assuming you have water kefir that has gone through its first fermentation, the rest of the process is easy!
Step One: Blend Additional Flavors
Combine your flavor additions in a blender, and add enough water kefir to blend fully. Once blended, pour the contents into a strainer to remove solids. Set juice aside.
Step Two: Combine Ingredients and Bottle
Combine your juice, water kefir, and sugar into your clean bottle. Seal and store in a warm spot for 1-2 days. Burp twice daily to release pent-up carbon dioxide. This will not inhibit the formation of bubbles, and it is a good way to guarantee you don’t accidentally have exploding bottles!
Step Three: Serve and Enjoy!
Once your kefir soda is bubbly, usually around 1-2 days, you’re ready to serve and enjoy!
Kefir soda is water kefir that has gone through a second fermentation, combining additional sugar with flavors of your choice. This second fermentation creates effervescence and infuses water kefir with delicious flavors.
Kefir soda is loaded with healthy gut microbes that help aid immunity and digestion. This is also a great low-calorie soda substitute that can help aid in weight loss.
Kefir is fermented sugar water with kefir grains that do the job of converting sugar to carbon dioxide. Kombucha, on the other hand, is made from fermented sugared tea. Tannins are required for the kombucha mother to ferment.

Water Kefir Soda
Equipment
- Ferment safe bottle with lid
- Cheesecloth or strainer
- Blender
Ingredients
- 24 Oz. Finished water kefir
- 1 tbsp Sugar
- 1 cup Chopped watermelon
- ¼ cup Sliced cucumber
- 4-5 Mint leaves
Instructions
- Combine watermelon, cucumber, mint, sugar, and 1 cup of water kefir in your blender. Blend until smooth.
- Strain through a strainer or cheesecloth. Discard solids.
- Combine fresh juice and the rest of your kefir into your ferment-safe bottle. Seal the bottle and store it in a warm spot for 1-2 days, burping at least twice per day to release pressure.