In Australia, we only have bicarbonate of soda and baking powder. The chocolate crinkles recipe I want to try out requires baking soda. Which can I use to substitute & how much?:confused:

Baking soda (Sodium bicarbonate) is the same as bicarbonate of soda.

I was about to say the same thing. In the United States, bicarbonate of soda, or sodium bicarbonate is called as baking soda. It is an alkaline salt.

When you have fruit in your recipe, the citric acid in the fruit reacts with the bicarb, causing CO2 gas to be released, which leavens the cake.

If your recipe does not contain an acidic fruit, you must use baking powder, which is a mixture of sodium bicarbonate and an acid salt. (usually "cream of tartar" (Potassium hydrogen tartrate, also known as potassium bitartrate)

When the two salts are mixed together in water, it causes the same acid alkali reaction.

Sodium bicarbonate is an alkaline salt, while potassium bitartrate is an acid salt.

Of course, you can simply mix the two checicals yourself, but baking powder is much more convenient.