Dear Xanthe: 'Why do some recipes use plain flour and baking powder instead of self-raising flour?'

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In the bag: Self-raising flour may lend itself to British cakes such as Victoria sponges
Self-raising flour lends itself to British cakes such as Victoria sponges Credit: Andrew Twort

Dear Xanthe 

Why do some recipes say use plain flour and baking powder instead of saying self-raising flour? What is in self-raising flour – is it as simple as a mixture of plain flour and baking powder, or a slightly different blend?

Dear Anon 

This is an excellent question. Self-raising flour is a very British ingredient; you won’t find it in American recipes, for example. I’ve always happily substituted baking powder and plain flour for self-raising, but for the definitive answer, I turned to Clare Marriage, founder of Doves Farm, who produces a wide range of organic flours.

“Historically, recipes began with plain flour and raising agent was added,” she says. “We’ve come a long way from using ground hartshorn (prepared from the horns of deer) in the 17th and 18th centuries as a raising agent to make cakes.

By the mid-19th century, American professor Eben Horsford discovered there was a chemical reaction in baking, and devised a unique mixture that became known as baking powder, a mixture of a carbonate or bicarbonate and acid. Today, choosing between plain flour plus baking powder, or self-raising flour, largely depends on what you’d like to bake and what other ingredients are going into the mix. It is, as is often the case with baking, all to do with alchemy.

“You will find that, often, continental cakes are characteristically denser than British cakes (and indeed sometimes yeast-based, such as babka or panettone) so will call for plain flour with added baking powder. Recipes for bakes such as scones or fluffy American-style pancakes may call for a little extra baking powder to give more rise.

“When it comes to bakes with more acidity, such as lemon cake, or some American recipes that use buttermilk or molasses, you will need to add bicarbonate of soda (or baking soda as often called in America) in place of baking powder. Self-raising flour is most commonly found in British recipes and is a combination of plain flour and added raising agents that are a balance of acid and alkali (the exact ones vary slightly depending on the brand of self-raising flour you buy), and is perhaps one of the original convenience foods.

“It is our culture of wonderful, fluffy, light-textured classic British cakes – the likes of Victoria sandwich and coffee and walnut cake – which self-raising flour lends itself to so brilliantly.

“If you only buy plain flour, then we recommend adding two teaspoons of baking powder to 100g of plain flour to make your own self-raising flour. It is important to measure them, mix and then sieve the mixture to ensure it’s thoroughly combined.”