Question: how much polysorbate 80 to use in bath bombs?
Answer: Many suppliers will tell you that you should add 1-3% of Poly 80 to your bath fizzies but I found that 2% makes them expand or they stay soft forever. The best rule that works for me is to use 1 part Polysorbate 80 to 2 parts of carrier oil or butter. So if you use 1 tablespoon of oil – add half tablespoon of Poly 80.