Self-raising flour vs plain flour with baking powder: Tips you need to know

Adding a little flour power to your baking is essential when making delicious sponge cakes, cookies and pastries. Nowadays there’s an abundance of different types of flours and self-raising agents available in the baking aisle, but if you’re going to bake right you need to know what makes them different. 

What exactly is the difference between self-raising flour and plain flour?

Plain flour

Plain flour, also known as all-purpose flour, is made up of 75 per cent wheat grain, with most of the bran and wheat germ taken out but leaving the endosperm to increase its shelf life. This kind of flour is ideal for most baking applications, for creating thicker sauces, and for coating meat or seafood.

Self-raising flour 

Self-raising flour has a very specific ratio of flour and baking powder. To replicate self-raising flour you’ll need approximately one teaspoon of baking powder and one cup of plain flour. However, many recipes ask for different baking powder to flour ratios in order to achieve the desired outcome – this is when a recipe will ask for plain flour and baking powder as separate ingredients. 

Speaking to The Guardian, baking guru Dan Lepard explains: “It’s a mixture of plain flour with bicarbonate of soda [sodium hydrogen carbonate], plus an acid powder [usually monocalcium phosphate in supermarket mixes].”

For example, our maple and banana bread has a heavier batter and requires more baking powder for it to rise. The recipe calls for three quarters of a teaspoon of baking powder and two cups of self-raising flour. It is for this reason, that some bakers, like the author of One Tin Bake Easy, Edd Kimber, will advise against substituting self-raising flour or you may find yourself with a less-than-desirable outcome. 

“No one really agrees on what the ratio of flour to baking powder is,” he said. 

Lepard suggests either combining 250 grams of plain flour, 10 grams of cream of tartar and 5 grams of bicarbonate of soda, then sifting “two to three times to mix evenly”, or simply 250 grams of plain flour plus 15 grams of baking powder (or about three teaspoons).

“Sometimes, a recipe already contains an acidic ingredient, such as buttermilk or soured cream, so it needs only bicarb to rise,” Lepard explains. “Whereas a banana cake, where the fruit makes it very alkaline, often needs extra acidity, so additional baking powder can be helpful.”

And just like all of us from time to time, baked goods need an extra lift, so don’t be scared to experiment.