is it ok to use "Self Raising" flour , instead Plain Flour with Baking powder/soda ??
even if the recipes says to use Plain flour + Baking powder ?
I dont want to throw out another cake due to Bitterness .
Self rising flour is formulated to approximately 1 teaspoon baking powder per cup.
If your recipe calls for more baking powder than 1 teaspoon per cup plain or includes both baking powder and baking soda then you will have to figure out how much additional leavening is needed.
Baking soda and baking powder, activate differently. baking soda needs an acid to activate. Baking powder contains the necessary acids to activate, and is double acting. Double acting baking powder, activates with liquid, and then a second time with heat. So baking powder activates as soon as liquids are mixed into the batter, then again when the batter/dough reaches 140°F (60°C).
If your original recipe only contains baking soda, the batter/dough will have one activation with liquid and acid contact. When using self-rising flour, which normally contains both baking soda and baking powder, it will get double activation. in some recipes, like cookies that can affect the texture.
In the US, self-rising flour has a much lower protein content than plain (all purpose) flour. So substituting self-rising flour for plain will affect the strength of the dough/batter; the rise; texture, and mouthfeel. For example, drop cookies, like chocolate chip, that require a stronger flour will be more cake like, rise less, and spread more with self-rising flour due to the baking powder and lower protein.
Some quick breads that require a stronger flour, will not rise as much.
So yes, you can substitute self-rising flour with plain flour. But there are some variables to consider when making the substitution.