I have a rinse-off conditioner formula I LOVE that is stable at 40 degrees up until about 7 weeks, at which point some separation is starting to occur. Nothing drastic yet, but there seems to be almost an inch of a yellowish layer forming on top. RT sample still looking great.
I used BTMS-50 at 10%, wondering if maybe it needed some other co-emulsifier? Cetyl alchol, cetearyl alcohol, e-wax, montanov 202, or...? Perhaps a little xanthan gum to hold it all together? I once had a lotion formula that was giving me similar problems and adding 0.25% xanthan completely took care of it.
I feel like this formula was almoooooosst perfect and just needs some slight tweak to make it stable.
Other ingredients, in no particular order:
Witch Hazel hydrosol
Aqueous extracts of various herbs
Ginseng Extract (caprylic triglyceride based)