How to make self-raising flour from plain (or all-purpose) flour and baking powder.
I use self-raising flour in a lot in my recipes and one question I get asked quite regularly is how they can be adapted to be made from plain or all-purpose flour with added baking powder.
There are lots websites and books about which suggest the correct quantity of baking powder to add to plain to turn it into self-raising, but annoyingly they don’t all agree.
Nigella suggests adding ½ tsp of baking powder and ½ tsp of bicarbonate of soda to 150g of plain flour, whereas Baking Mad suggests adding 2 tsp of baking powder to 150g of flour. Then King Arthur Flour proposes adding 1½ tsp of baking powder and ¼ tsp of salt to 120g of flour. As you can see the suggestions aren’t even close!
So how how on earth do we know how much baking powder is needed to make self-raising flour?
My solution (the same as always)… to get into the kitchen and get baking.
I decided to make lots of simple vanilla cupcakes, one batch using self-raising flour and then all the others made with plain flour and subtly different amounts of baking powder.
NOTE – The vanilla cupcake recipe I used for these experiments is ever so slightly different from the recipe linked above, as in that recipe I add extra baking powder. For this experiment I decided to leave that out as I felt it gave a cleaner comparison.
As expected, the more baking powder that’s used the greater the rise.
You can see the cupcake made with just plain flour is much shorter than the others. Also, as it baked a lot of the fat bubbled out leaving it dry and dense. If you ever have a cake that doesn’t rise as expected, it would suggest that your baking powder isn’t working properly (or you’ve use bicarbonate of soda instead – something I’ll be writing a post about soon).
If you want to check your baking powder you can add a little to some boiling water. If it bubbles (the bubbling will be quite furious), you can get baking. If not, it’s time to get to the shops for a fresh packet.
Going to the other end of the scale, when you compare the cupcake made with self-raising flour to the cupcake made with 1 tsp of baking powder per 50g of plain flour, you can see that the plain flour cupcake is taller (especially at the sides) and flatter on top. I like a tall flat cupcake which is why I often add additional baking powder to my recipes when using self-raising flour.
So, much like in goldilocks and the three bears we have one cupcake that’s too small and one cupcake that’s too big and fluffy. All we need now is a cupcake that’s just right…
How much baking powder should be added to plain flour to make self-raising flour?
The answer is 1 tsp of baking powder per 100g of plain flour.
You can see that the cupcakes are not only nearly identical in terms of height, they’ve also got a very similar dome on top.
Is that a heaped teaspoon or a level teaspoon?
Always a level teaspoon (much more accurate as some teaspoons will hold a bigger heap than others depending on their shape).
Also, I always use a measuring teaspoon rather than one I’d use to make a cup of tea as again it’s much more accurate.
Is self-raising flour in the UK the same as self-rising flour in the US?
Unfortunately not, so if you find a recipe that calls for one of these and you’re not in the right country then I’d suggest using a homemade version.
The version I’ve shared here is for UK self-raising flour (as that’s what I use and what I can get hold of in the shops for my testing). US self-rising flour has a lower amount of baking powder and also contains added salt.
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How To Make Self-Raising Flour
- 100 g plain or all-purpose flour
- 1 level tsp baking powder - I always use a measuring teaspoon rather than one I'd use to make a cup of tea as it's much more accurate.
- Put your ingredients (100g plain flour, 1 tsp baking powder) into a large bowl.
- Mix together (I like to use a whisk) until the baking powder is evenly distributed in the flour.
- Your self-raising flour is now ready to use in your chosen recipe.
Any nutritional information provided is the estimated nutritional information per serving. Please refer to my guide to Charlotte’s Lively Kitchen nutritional information if you would like to learn more about how this is calculated.