Take a small spoonful of baking soda and put it in an empty mineral water bottle, then fill it with cool or pure water (about 500 ml), dissolve and shake it well.

The soda water made in this way has a bitter flavor and does not taste very good. You can add an appropriate amount of sugar to dilute the bitter flavor of baking soda.

Soda foam can improve the taste, you can add a small amount of citric acid in the made soda (can also be replaced by white vinegar), sealed and shaken well, in order to dissolve carbon dioxide in the water. After refrigeration, the taste is also greatly improved.