Baking powder vs baking soda
Q: Is there a difference between baking powder and baking soda?
A: Both baking soda and baking powder are chemical leaveners – this means that they both react chemically to create carbon dioxide bubbles in your bake to help it rise. But they do work in slightly different ways.
Let’s first start with baking soda. Now this is known here in Australia as bicarbonate of soda. It is an alkaline, and it will only react to create carbon dioxide if it comes into contact with an acidic ingredient, like lemon juice, vinegar, buttermilk or yoghurt. It can also be activated by less obvious acidic ingredients like brown sugar, golden syrup and honey. So when you are using it in your baking you need to make sure there is also some sort of acidity in the recipe to activate it.
And then there is baking powder which is based on bicarbonate of soda but it also contains an acidic element to create the reaction. It is usually a combination of bicarbonate of soda, a little moisture absorber such as rice flour or cornflour, which prevents the baking powder from being activated prematurely, and one or two powdered acids.
Having these acids in the baking powder means you don’t need to add a separate acidic ingredient, such as lemon juice, in your mixture.
These powdered acids are activated by moisture and/or heat which, in turn, react with the bicarbonate of to create bubbles of carbon dioxide.
It’s also interesting to note that bicarbonate of soda has four times the leavening strength of baking powder!