I was making some banana bread. I didn't have any self-raising flour so made my own by adding baking powder (BP).

An unfortunate senior moment saw me add the BP to the wet ingredients instead of into the flour...sigh...

I figured it would still work. After all, the BP is just another ingredient, right?

The final result tastes great, but it didn't rise at all. I don't understand why that would happen, can someone explain why the BP should be added to the flour?