The main difference between All Purpose Flour and Self Raising flour is the addition of baking powder and salt in the latter. This means that Self Raising flour already contains the leavening agents needed to make baked goods rise, whereas All Purpose Flour requires you to add these agents separately. It's like the difference between a ready-to-go coffee and a bag of coffee beans, both will get you caffeinated, but one requires more effort.
Now, you might be wondering why this matters, after all, flour is flour, right? Well, not exactly, using the wrong type of flour can affect the texture and taste of your baked goods. For example, if you use Self Raising flour to make a cake that already includes baking powder, you might end up with a cake that's too dense or has a soapy taste. It's like adding too much salt to a dish, it can ruin the whole thing.
So, why should you care about the difference between All Purpose Flour and Self Raising flour? Well, for one, it can make a big difference in the quality of your baked goods. Imagine you're making a birthday cake for a loved one, and it turns out dense and unpleasant, that's not exactly the impression you want to make. By using the right type of flour, you can ensure that your baked goods turn out light, fluffy, and delicious.
Difference Between Strong Bread Flour And Plain at Ian Milligan blog