Bicarbonate of soda, or baking soda, is an alkali which is used to raise soda breads and full-flavoured cakes such as gingerbread, fruit cake, chocolate cake and carrot cake. It needs an acid (as well as moisture) to activate it so is often combined with cream of tartar, yogurt, buttermilk or milk.
Bicarbonate of soda gives off carbon dioxide, which expands in a mixture. Once the mixture is cooked, the carbon dioxide is replaced by air, leaving a light cake or bread.
As with all raising agents, use the amount specified in the recipe. Adding extra bicarbonate of soda can result in a peaked or collapsed cake, a strong unpleasant flavour and a greenish tinge.
In an airtight container in a cool, dry place. Make sure your bicarbonate of soda is in date before using.
Try a classic soda bread if you're new to baking, for a simple but satifying no-knead bake.
Add tiny bubbles to honeycomb by stirring bicarb into the caramel before setting.