Cool-down phase
The stage of a recipe (around 40°C) where heat-sensitive actives, fragrance, and preservatives are added.
Most lotions and creams are made by heating the water phase and oil phase separately to 70°C, combining them, then blending. Many useful ingredients — vitamins, fragrances, most preservatives — are damaged by sustained heat. The cool-down phase is when the emulsion has cooled to below 40°C (sometimes specified as below 45°C) and these delicate ingredients can be added safely.
Ingredients commonly added at cool-down:
- Preservatives (phenoxyethanol, Cosgard, Liquid Germall Plus, Optiphen)
- Fragrances and essential oils
- Vitamins (panthenol, niacinamide)
- Most botanical extracts
- pH adjusters