- Lye Calculation Fundamentals
- Saponification (SAP) Values:
- Definition: The amount of lye required to saponify 1g of oil.
- Example: Coconut oil SAP = 0.183 (NaOH), Shea butter SAP = 0.128 (NaOH).
- Using a Soap Calculator:
- Input oils/weights → calculator outputs lye and water amounts.
- Importance of superfatting (5–8% for moisturizing).
- Safety Margin: Always double-check calculations to avoid lye-heavy soap.
- Properties of Oils
- Coconut Oil: High cleansing, bubbly lather; can be drying in excess.
- Olive Oil: Mild, moisturizing; produces a soft bar with stable lather.
- Shea Butter: Adds hardness and creamy lather; high in vitamins.
- Palm Oil: Firm bar, stable lather (use sustainable sources!).
- Castor Oil: Boosts lather; use sparingly (5–10% of total oils).
- Balancing a Recipe
- Hardness vs. Moisturizing: Coconut (hardness) + Olive (moisture).
- Lather: Coconut + Castor for bubbles.
- Example Recipe:
- 40% Olive Oil, 30% Coconut Oil, 20% Palm Oil, 10% Castor Oil.
- Activity: Practice Calculating a Basic Recipe
- Task: Use a soap calculator to determine lye/water for 500g of oils.
- Input: 50% Olive Oil (250g), 30% Coconut Oil (150g), 20% Palm Oil (100g).
- Output: Lye (NaOH) = (250×0.134) + (150×0.183) + (100×0.141) = 72.05g.
- Submission: Learners submit a screenshot of their soap calculator results.