What are the phases in a formula?
Short answer
Groups of ingredients handled together at the same stage: water phase, oil phase, actives, preservative and pH adjustment.
Explanation
The book uses a consistent structure. Phase A: water or hydrosols with water-soluble ingredients. Phase B: oils, butters and the emulsifier. Phase C: heat-sensitive actives added during cooling. Phase D: preservation. Phase E: pH adjustment.
A typical cream in the book is 55–75% water phase, 15–27% oil phase (including 3–5% emulsifier), 2–8% actives, about 1% preservative, and pH adjuster as needed.
What to do
- Weigh each phase into its own sterilized container before you start heating.
Source: The Big Book of Homemade Skin Care — All formulas in The Big Book of Homemade Skin Care