As I find most commercial soda too sweet, I started experimenting with making it at home. It's incredibly easy to create lots of bubbles in your drinks so I'd like to share it with you.
an empty bottle, a small funnel, teaspoon, baking powder, citric acid, juice or tea or whatever drink you want to use. the citric acid reacts with the baking powder (bicarbonate) and creates the bubbles.
the drink in the bottle and add a teaspoon of baking powder. shake briefly to make sure it dissolves well in the drink, then add 2 spoons of citric acid and quickly close the bottle (before bubbles escape!)
Enjoy your drink