Bring water to a simmer, add sugar, stir and dissolve. Let cool.

When the water is warm (but not hot) to the touch, add 1/2 cup lemon juice, 1/2 cup lime juice and all of ginger bug and mix well.  Taste.  This is approximately what your soda will taste like. Add additional 1/4 cup each of lemon and lime juice, if desired.

Transfer to a 2-quart ball jar or demijohn and leave at room temperature for at least 3 days. Stir it every day to prevent mold from forming on the surface. Look for visible signs of fermentation via a slight fizziness. Even a slight fizz is a good sign that the carbonation will build rapidly when transferred to the soda bottles. You can let it ferment longer than 3 days if you’d like a less sweet soda as the bacteria will continue to feed on the sugar (similar to kombucha). Taste it as you go to get the sweetness you desire.

Transfer to soda bottles using a funnel or a pourable measuring cup.

Keep the soda bottles at room temperature and CHECK EVERY DAY.  Open the bottles carefully to let some of the gasses escape. Do this over the sink as sometimes you’ll get a bubbling over, like in this video of me opening my fermented blueberry soda. Once it’s carbonated, transfer the bottles to the refrigerator where the fermentation will dramatically slow down.

Enjoy!