Instructions
To make your own sherbet, you will need:
Icing Sugar, Bicarbonate of soda (bicarb) and Powdered citric acid (from the chemist)
Then just mix the ingredients together and keep everything dry (this is really important).
Our recipe is 4 parts icing sugar , 2 parts citric acid, and 1 part bicarb.
How does it work
The acid reacts with the bicarb, it creates the fizzing sensation on your tongue.
When the two powders dissolve in the saliva on your tongue, they begin to react:
Citric Acid + Bicarbonate of Soda
makes
Sodium Citrate + Water + Carbon Dioxide
It is the carbon dioxide that gives the fizz, forming bubbles directly on your tongue.
There is another surprise hiding in the equation: endothermy.
Thats the pleasant cooling sensation from the fizzing.