Emulthix: A light to medium weight lotion with botanicals, Emily asks: I love the sounds of cold emulsions and have always wanted to try one, but I have been worried that there would be beasties in my oil if I didn't heat and hold it - I'm guessing that this is overridden by the preservative?
I know, it's weird, right? I'm normally all about the heating and holding and all that good stuff, so using cold emulsifiers is a strange thing to me, too!
In general, we don't worry about beasties in our oil soluble ingredients as almost all of our potential contaminants are found in the water phase of our products. When we're making cold products, we need to be especially careful to clean our creating containers - a spray with 70% alcohol is a great choice - and utensils before using them. Clean your stick blender or mixer well with alcohol, and only use distilled, reverse osmosis, or de-ionized water.
Only use clean containers when you're making products. Do not re-use old ones. And don't clean ones that are fresh from your supplier. It's assumed they are clean, and by cleaning them, you can introduce icky things that ruin the packaging.
And use a good broad spectrum preservative at the recommended level. I like to use liquid Germall Plus at 0.5% in most of my products, and I rarely have problems.
Preservatives should be there to battle the things to come, not the things already in the mix, so if we adhere to these good manufacturing processes, we'll have a nice, clean product!
Why do we heat and hold with anhydrous (non-water containing) products?
How to preservatives work?