Q: "What is the difference between baking soda and baking powder?"
Noelene Hatherly, via email
A: Nutritionist and recipe writer Chrissy Freer says:
“Both baking soda and baking powder are leavening agents that produce bubbles of carbon dioxide to help baked goods rise, but they are used under different circumstances.
Baking soda, also known as bicarbonate of soda, is a pure leavening ingredient and needs to be mixed with moisture and an acidic ingredient (such as honey) to produce a reaction. It’s important to note that when using baking soda in a recipe, you must bake immediately after mixing, since it will start to rise quickly.
Baking powder is a mix of baking soda, cream of tarter (an acidic agent) and starch. There are three types of baking powder, the most common being ‘double-acting’. This means that batter can stand for a little while before baking; some bubbles form at room temperature, but the majority of the gas is released in the oven with heat. Generally, baking powder can’t be substituted for baking soda, because the excess acidity can affect flavour and texture.”