How to Make Lacto-fermented Watermelon Soda

Lacto-fermented Watermelon Soda

Fresh watermelon, sugar and a stater culture is all you need to make a lacto-fermented watermelon soda!  

Course Drinks
Cuisine American
Prep Time 20 minutes
Cook Time 10 minutes
Total Time 30 minutes
Servings 1 quart
Author Craig Fear



  1. Boil sugar in water for a few minutes and stir to dissolve.  Cool to room temperature.
  2. Cut watermelon into chunks and puree in blender or food processor.
  3. Strain out in a strainer covered with cheesecloth to get the watermelon juice.

  4. Add the juice and the whey to the sugar water in a 2 quart glass ball jar or demijohn

  5. Let it ferment on your counter for at least 2 days and up to 10 days. The longer you let it ferment the less sugar there will be as the bacteria will consume and convert the sugar during fermentation. Swish the soda around once a day to prevent mold from forming on the surface.

  6. Transfer to soda bottles. Soda bottles increase the natural carbonation.
  7. The carbonation will increase rapidly. Be sure to release the pressure that builds every day until you’re ready to transfer them to the fridge. Do this over the sink or outside as the geyser effect is common.