Self rising flour is basically just a pre mixed flour that has all the needed ingredients combined for baking with, which includes the all purpose flour, baking powder as a leavening agent and a bit of salt.
Self rising flour is a very popular flour used in Southern baking, which makes for creating perfectly tender, pancakes, biscuits and even quick breads without needing to measure out the other individual dry ingredients like the baking powder and salt.
The leavening agents like baking powder are distributed flawlessly throughout the self rising flour and ensures the baked goods have uniform rising.
And in the United States, self rising flour is usually milled from soft winter wheat, which results in a lower protein content that also yields a nice delicate and fluffy crumb.
And because of the active baking powder in self rising flour, the self rising flour also has a shower shelf life than regular flour as self rising flour loses it's rising power within 6 months although it can be used for other goods or even have more baking powder added.
Self rising flour can also be easily made at home, if you have no self rising flour.
All you need to make self rising flour is some all purpose flour, baking powder and some salt.
For every 1 cup of all purpose flour, you mix in 1-1/2 teaspoons of baking powder and 1/4 teaspoon of salt.
If you have a recipe that calls for all purpose flour but you only have self rising flour, you can also use it, but you must also omit the extra baking powder and salt that is called for in the recipe.
And outside of the United States such as in Australia or the UK, self rising flour is often sold as self raising flour, which often includes the baking powder but no added salt.