Understanding Oils and Butters in Saponification

Every plant oil brings unique characteristics to handcrafted soap. The key to formulating a world-class bar lies in balancing hardness, cleansing power, lather quality, and skin conditioning.

Key Oils and Their Characteristics

1. Olive Oil (Oleic Acid)

• Role: Extreme mildness and nourishment. Perfect for sensitive skin and baby soaps (Castile soap).
• Cons: Slow trace, soft bar out of the mold requiring extended cure time (4 to 8 weeks).
• Recommended Usage: 30% to 70%.

2. Coconut Oil (Lauric & Myristic Acids)

• Role: Produces fluffy, abundant lather, hardness, and high cleansing power.
• Caution: At high ratios (>30%), it can be drying. Pair with a higher superfat percentage (8% to 10%).
• Recommended Usage: 15% to 25%.

3. Shea Butter (Stearic Acid & Unsaponifiables)

• Role: Provides bar hardness, creamy lather longevity, and luxurious skin protection.
• Recommended Usage: 10% to 20%.

Balancing Formulas with the INS Factor

The INS Factor (Iodine Number - Saponification) measures overall bar balance. The ideal target score for a well-balanced bar is approximately 160.

• High INS (>170): Hard bar, fast trace, potentially lower lather.
• Low INS (<140): Soft bar, gentle on skin, slower drying.

Download our Free Soap Formulation Kit to calculate INS values and superfat percentages automatically!