I don't use a lot of self-rising flour, so rather than store it, I make it as I need it. VERY easy, 2 or 3 ingredients). Self-rising flour contains baking powder and because baking powder will expire after a period of time you need to use up self-raising flour more quickly than plain flour.
In the US self-rising flour usually contains added salt which can lead to some of the recipes tasting a little too salty if this flour is used. I cook low sodium and do not add additional salt to a recipe if using homemade self-rising flour.
There are many self-rising flour "recipes" available--this is the simple one (with better instructions for larger quantity self-rising flour).
Ingredients
FOR A SMALL BATCH:
- 1 cup all-purpose flour
- 1 1/2 teaspoons baking powder
- 1/4 teaspoon salt
FOR A LARGE BATCH:
- 4 cups all-purpose flour
- 2 tablespoons baking powder
- 1 teaspoon salt
INSTRUCTIONS
- Add ingredients for desired batch size to a large bowl. Whisk until combined and use as directed in the recipe in place of self-rising flour.
Storage: If you want to make a larger batch of homemade self-rising flour for later, store it in an airtight container, label and date it, and keep it with your other baking ingredients in a cool, dry place.
from https://www.mybakingaddiction.com/how-to-make-self-rising-flour/