BASIC BATH MELT RECIPE
1 part citric acid
2 parts cocoa or shea butter
3 parts baking soda
16% citric acid
32% cocoa or shea or mango butter
48% baking soda
1 to 2% fragrance oil
Melt the cocoa or shea butter in a heat proof container in a double boiler until liquid. Remove from the double boiler, then add the baking soda and citric acid and stir well. Add oil soluble colouring (for instance, powdered chocolate colouring or micas), and fragrance oil. Pour into molds and let set. If you can set them in the fridge, all the better: They'll be harder sooner, and, if you're using all cocoa butter, they will get a lovely shine that makes them look even more chocolate-y.
(As you'll remember from the butters post, shea butter isn't as hard as cocoa butter, so making these with all shea or mango butter will make them softer. I recommend using a 50-50 mix so you can ensure your melts will be hard enough to package and transport. Or feel free to use only cocoa butter. It's less expensive than shea or mango butter, and it is very moisturizing in the tub.)
You can use melt & pour soap or chocolate molds or silicone ice cube trays for these bath melts, but please make sure you don't use those molds for future edible projects (if you are fragrancing your melts). Ideally, a 100 gram batch would make 5 - 20 grams bath melts. You don't want to use more than 1 or 2 per bath because you don't want to get a ring around the tub!
MAKE THEM FANCY!
Melt, colour, and fragrance some cocoa butter and dip in the hardened melts to make them look like truffles. Or you can melt, colour, and fragrance your cocoa butter and drizzle it over top.
Anything you can do with chocolate, you can do with your bath truffles. You can roll them in coloured fine sea or Epsom salts to look like sugar. You can pour them in layers, then cut them to make them look like layered mints or tiger butter.
Package these in candy foils to make them look tasty! But label them very clearly with DO NOT EAT because someone is going to try to eat the wonderful smelling treats you've made!
AS A NOTE... Bath melts will make your bathtub slippery, so you can add an emulsifier to this mixture. You can add something like emulsifying wax at 4% (I do have an emulsification post coming up, so if you're not sure about it, then wait until I post that next week!) and reduce your butters to 28%.