BICARBONATE OF SODA
Bicarbonate of soda, also known as sodium bicarbonate or baking soda, is a pure leavening or rising agent. It reacts with the acidic components of batters (think cocoa, lemon juice or cream of tartar) and causes the batter to expand and rise.
Has your bicarb been knocking around your pantry for a while? To test if it’s still active, mix it ½ t with vinegar. If it fizzes and bubbles, it’s still good to use. Discard if not.
CREAM OF TARTAR
Cream of tartar (also known as potassium hydrogen tartrate) is made from tartaric acid, which is an acidic byproduct of turning grapes into wine. Tartaric acid is partially neutralised by the addition of potassium hydroxide, which results in the less acidic cream of tartar. Because of the significant difference in acidity, cream of tartar is not a substitute for tartaric acid, and vice versa.
Cream of tartar is normally used along with bicarb to create a raising agent, causing your bakes to rise. (In essence, this is baking powder – see below). Cream of tartar can also be added to simple syrups to prevent the formation of sugar crystals. It can also be used to stabilise meringues that are perfectly peaked and fluffy.
No cream of tartar? For every 1 teaspoon cream of tartar required, substitute with 2 t of another acid such as lemon juice or vinegar and mix with baking soda.
Baking powder is, quite simply, a pre-packaged version of bicarbonate of soda and cream of tartar which, when added to batters, will make them rise.
Is your tub of baking powder still good to use? Test if it’s still good by mixing ½ t baking powder with a little water. If it foams, it’s good to use.
Make your own baking powder from baking soda and cream of tartar: mix 1 part baking soda to 2 parts of cream of tartar.