I'm trying so hard to get through your comments, but I'm still back in June. There are just so many good ones, it's hard to answer them with a quick comment or two.
Formulating a Cream Cleanser for dry skin, Afriyie's Faith asked: Hi Susan, thank you so much for creating an awesome blog and for sharing your knowledge! I have very sensitive skin so I would like to make this cleanser with simple ingredients such as plant oils and extracts. How do I add the SCI to the plant oils? Would I need a preservative and emulsifier? Many thanks
CREAM CLEANSER FOR DRY SKIN
20% cocamidopropyl betaine
25% BSB or SMC or SMO Taurate
10% C12-15 alkyl benzoate
6% stearic acid
5% PEG-7 glyceryl cocoate
0.5% extract of choice
0.5% to 1% preservative of choice
Weigh the SCI, stearic acid, and cocamidopropyl betaine in a container and put into a double boiler until it is well melted. In a second container weigh the rest of the ingredients except the Crothix, preservative, and extract and heat in a double boiler.
Here's the thing - sodium cocoyl isethionate (SCI) is pretty particular when it comes to melting, and it won't melt in oils. It isn't that water soluble either, so we need to melt it in another surfactant the way I have done in this formula. It melts really well in cocamidopropyl betaine, which increases mildness, so that's why I've written this formula this way.
What kind of preservative? I'd use something that was water and oil soluble to make sure it is super effective. (Read this post for more information!)
You wouldn't need an emulsifier as the prills would just float in the oil in little spheres. When you add water, it'll foam up and wash your face.
Actually, this sounds like something fun I'll put on my to-formulate list!
So the short answers to your questions are...
You could just put the prills, noodles, or flakes in oil.
You don't need an emulsifier as the prills, noodles, or flakes will just sit in the oil.
You will need a preservative.