Place a few tablespoons of water kefir grains into the bottom of a quart jar.
Add 1/4 cup of sugar and raisins.
Fill up your jar with water, leaving about an inch of space at the top. Stir gently with a long spoon to dissolve the sugar, being careful not to break up the tibicos.
Cover the jar with a lid and set in a dark and out of the way spot for a few days. Stir it occasionally, and start checking the sweetness level after 2 days. I don’t like mine very sweet, so I generally let it go for 3-4 days. You should see little bubbles floating to the top.
Flavoring Tea
Once it’s at the sweetness level you desire it’s time to think about the flavoring you would like for you soda. You can use fruit juice, flavored teas, or anything you think would make a good soda! For this one I’m using lavender and elderflowers.
Start by bringing a quart of water to a boil and steeping the tea.
Steep for several hours to make a strong tea and cool to room temperature.
Strain out the flowers/herbs and pour the tea into a half gallon jar.
Strain the water kefir into the half gallon jar with the tea. (Reserve the tibicos or the next batch.)
Bottle the soda and leave the sealed bottles out at room temperature for a day or two, then refrigerate before opening.
Notes
Careful when you open it as it will be carbonated and might be explosive! It probably won’t, especially if your flavoring isn’t sugary as that feeds the carbonation.