Self-raising flour and plain flour are both staples in baking, but they are not interchangeable. Self-raising flour already has a raising agent, such as baking powder or yeast, mixed in, while plain flour does not. Self-raising flour may also contain added salt.
When to Use Each Type
Self-raising flour is typically used for cakes, muffins, and other baked goods that need to rise. Plain flour is better suited for roux, coatings for fried dishes, and recipes where you want to control the leavening yourself.
Because of the added ingredients, self-raising flour has a shorter shelf life. If it goes past its use-by date, it may not rise properly, resulting in flat cakes and muffins. Always check the dates on your baking supplies.
Can You Substitute One for the Other?
No. Substituting self-raising flour in a recipe that calls for plain flour will change the taste and consistency. For example, using self-raising flour in a roux or soup will cause it to bubble and swell due to the raising agent.
However, if a recipe requires self-raising flour and you only have plain, you can make your own. Simply combine one and a half teaspoons of baking powder and a quarter teaspoon of salt with one cup of plain flour. Whisk well to blend. Adjust quantities proportionally for larger amounts.
