Q&A: Why use cream of tartar instead of citric acid for fizz in bath bombs or solid bubble bath?

I wrote this last year, but didn’t share it, for some strange reason. It was supposed to come after the ingredient entry for cream of tartar last November… So why use might we use cream of tartar (INCI: Potassium bitartrate) instead of citric acid? Why do I use it in my bubble bath bars instead of citric acid?…