Learning to formulate: The cool down phase, MSC asks: What is the maximum percentage of ingredients, specifically oils, that I can add in my cool down phase? I recently read that it is better not to heat Argan oil, which I would like to use. If I wanted 4% of my oil to be Argan could I add that during cool down, at the same time as my preservative and essential oils, or would that not work?
You're asking two questions here, so let's tackle each one individually.
Is it okay to heat argan oil? (Answer is originally from this post.) Yes. There is no reason not to put it in the heated phase of our products. There's a perception out there that some carrier or exotic oils are fragile creatures, that they can't handle heating and holding at 70˚C/158˚F. They can. The smoke point on these oils is much much higher than the heating and holding temperature, and you are doing them no harm by heating them.
Does heating and holding damage our oils?
Heating, holding, freezing, and thawing our oils
Why we heat & hold ingredients
Why we heat & hold our ingredient separately
Why? Because these ingredients don't get the benefit of the heating and holding phase, and we really want that process to happen as it's an essential part of creating a stable emulsion. (Yes, you can create an emulsion by putting your ingredients in the microwave long enough to melt, but it isn't going to be stable, and runs the risk of separating or failing!) If you have a ton of oil soluble ingredients in the cool down phase, you aren't heating and holding them, which means they might not emulsify as well.
So to answer the question - argan oil should go into the heated oil phase with your other oils and your cool down phase should be as small as you can make it!
How do you know into which phase we should add an ingredient?
How do you know how much of each ingredient to add to a product?