Baking powder

Baking powder is a combination of:

• one part baking soda (bicarbonate of soda) to two parts cream of tartare (tartaric acid)

As the baking soda is a alkaline, when combined with the tartaric acid and a liquid it begins to ferment, forms CO2, and thus allows products to aerate.

But the very thing that makes baking powder work also makes it unstable and gives it a short shelf life, as eventually the two chemicals cancel each other out. When this happens the baking powder is dead and any scones, etc made from it will not rise.

Purchasing the two chemicals separately and making your own baking powder will greatly increase the shelf life and always ensure you have a good, workable baking powder. Alternatively, purchase baking powder in small amounts and use frequently.

Baking soda can also be used as a raising agent (as for Irish soda bread), in this case buttermilk is normally used (or milk with a small amount of vinegar added). This acidity activates the alkaline of the baking soda to produce CO2