I have this well-rated chocolate cake recipe that I have not baked yet.
It's ingredients (among others) are
- 175g self-raising flour
- 1 tsp bicarbonate of soda
My understanding is that soda is needed to make the cake fulffier, and it only works when it is dissolved in vinegar (or there is something acid in the batter, e.g. kefir). And there are no acidic ingredients in this recipe (sunflower oil, self-raising flour, cocoa powder, bicarbonate of soda, caster sugar, golden syrup, eggs, semi-skimmed milk).
So what's its purpose here?
Best Answer
Both cocoa powder and milk are acidic, and will be reacting with the soda here. Bicarbonate of soda will react with any acid, not only vinegar.
There is also a process called thermal decomposition, where the soda releases CO2 under high temperature without needing an acid, although less than it would in a reaction with an acid and leaving a compound with an unpleasant flavour. See Wikipedia for more detail:
In your recipe, I imagine the soda reacts with the acidic ingredients to avoid this important taste.