Saundra Kamman of HerbN Tea led a class in the central library to learn two different methods for creating your own personal sodas. First is syrup (infused flowers like Lavender or fruits like cucumber) + soda water. The 2nd is more interesting. Everyone got hands on chopping and pouring for the latter, and each of us brought a bottle home. Here's a basic ginger ale recipe:
Chop organic ginger to small (mm) size - no peeling needed.
Cook in filtered or distilled water for some time.
Cool to room temperature.
Add organic or wild honey (unfiltered). Mix well.
In each 1-litre plastic bottle -- has to be plastic for elasticity, add 1/4 teaspoon of wine yeast.
Pour above liquid till 1/4 of bottle.
Fill with still water.
Wait ~1 day, depending on temperature, until the pressure of fermentation making the bottle very hard.
After a day, I drank some, added the juice of one grapefruit to feed the bacteria, and put in fridge. The bottle re-pressurized quickly. I drank some (diluted with water) every day for a week.