Back to Basics: Bath bombs, Annie asks: I found your link when I was enquiring on Google as to why cornstarch is used. I really couldn't find a valid reason and didn't want to waste time and ingredients. I always go to you - my first place to enquire on anything technical as well. It's coming up Christmas time and, because I make soaps and cosmetics, my friends presented me with a challenge for bath bombs, of all things, so I'm lying in bed researching.
I've never found a good reason for including corn starch, so I don't use it. Bath bombs are a chemical reaction between an acid - citric acid - and a base - baking soda. Add water and they fizz like crazy! I use an oil to bind it all together, and the fragrance and colour make the bath bomb fun and fragrant. Corn starch doesn't add to the reaction and doesn't seem to add anything to the hardness or cohesion of the bath bombs I make, so I don't bother with it.
But this is just my opinion, and I want to know what you have to say! If you do use corn starch in your bath bombs, why? How much? How do yours compare to those without? Give us some of your thoughts on this topic!