Btw. I am legally allowed to drink beer now and still prefer drinking apple juice, so it certainly has done no harm.
Step 1: Ingredients and Chemistry
- 4*1.6 g baking soda
- 0.3 g soy lecithin
- 5 g citric acid
- 1 pint of apple juice
- Analytical balance
Chemistry and math (yes, they can be fun ;-)):
Baking soda also known as sodium bicarbonate or sodium hydrogen carbonate reacts with an acid to carbon dioxide (among other products):
With citric acid baking soda reacts to trisodium citrate, water and carbon dioxide:
They are the main ingredients in sherbets and responsible for the fizzing. In order to stabilize the carbon dioxide bubbles, soy lecithin is used.
Soy lecithin is a phospholipid, with a hydrophilic 'head' (attracted to water) and a hydrophobic 'tails' (repelled by water). The water-loving ends of the lecithin orient themselves towards the water molecules and thereby stabilize the foam.
In order to calculate the ratio of citric acid to baking soda take a look at the second equation. Citric acid has three protons, therefore for each molecule of citric acid three molecules of baking soda are needed.
3 mol baking soda are 252.03 grams and 1 mol citric acid are 192.43 grams. So if we are using 5 grams of citric acid as in this example we will need about 6.55 grams of baking soda.
Step 2: Mixing
Fill up four glasses with a 1/4 pint each. You will need 1.64 grams of baking soda for each glass. Simply pour the baking soda into the glass and it will immediately start to foam.
Enjoy your drink!
PS: Thanks to kiteman for helping me out with the title and providing me with the fun fact that "fancy a sherbert" between British men means "would you like a beer?"