baking powder

baking powder is essentially the combination of an alkali and an acid - if you mix the two, they give off carbon dioxide which when added to a cake batter makes them rise.

in the case of baking powder, the acid takes the form of cream of tartar and the alkali is bicarbonate of soda. both are dry, so when they are combined, remain inert (don't do anything) until a liquid is added, then fizzing and all hell breaks loose....not really about hell breaking loose. if you're on the ball, you'll realise that because cream of tartar is an acid, you'll be able to replace it with vinegar, another acid which should be fairly easy to find around the house, if not in the pantry.

so how to make baking powder? so simple. two parts cream of tartar to one part bicarbonate of soda. mix it together and there you have it. this is more potent than the store bought variety, so you only need half as much. if you don't think you can remember to use just half, just add one part cornflour to the bicarbonate of soda and cream of tartar mixture, mix well, and use it as you would regular baking powder.

if you want to perform amazing feats with children, this is a good volcano ingredient - use vinegar with the bicarbonate of soda with food colouring. this is especially good with younger children who are easier to impress. with teenagers, one might have to resort to making fireworks, something else i've made in another life, but that's another story for another time.