Superfat in soap making refers to the excess oils and butters in a finished bar of soap that have not undergone saponification and thus remain as unsaponified fats. This intentional excess ensures a milder, more conditioning soap bar.
Understanding Superfat
When making soap, oils and fats are combined with a lye (sodium hydroxide for bar soap, potassium hydroxide for liquid soap) solution. This chemical reaction is called saponification, where fats are converted into soap. Superfatting involves formulating the recipe with more oils than the lye can completely convert into soap.
How Superfat is Achieved
- Lye Discount: The most common method involves calculating the amount of lye needed to saponify all the oils and then intentionally using a slightly lesser amount of lye. This ensures that a percentage of the oils remains unsaponified.
- Adding Oils at Trace: Some soap makers add a portion of their superfatting oils (often luxurious oils or butters) after the soap batter has reached "trace" (a pudding-like consistency). This guarantees these specific oils remain unsaponified.
It's important to note that superfatting can be incorporated into cold process and hot process soap making methods. However, it is not possible to control or create a superfat with melt and pour soap bases, as these are pre-saponified soaps.
Why Superfat Your Soap?
Superfatting offers several benefits that enhance the quality and user experience of handmade soap:
- Increased Mildness: The extra oils provide a protective barrier on the skin, reducing the harshness that can sometimes be associated with soap and making it gentler for sensitive skin.
- Enhanced Moisturizing Properties: The unsaponified oils nourish and moisturize the skin, preventing it from feeling dry or stripped after washing.
- Improved Skin Conditioning: These extra emollients contribute to a softer, more luxurious feel, improving the overall conditioning of the skin.
- Safety Net: A superfat ensures that all the lye has reacted with the oils, preventing any "lye heavy" or caustic soap, which could irritate the skin.
Typical Superfat Percentages
The ideal superfat percentage can vary depending on the desired properties of the soap and the oils used. Generally, a higher superfat percentage leads to a more moisturizing and gentler bar, but too high can result in a softer bar with a shorter shelf life and a greasy feel.
| Soap Type | Typical Superfat Range | Characteristics |
|---|---|---|
| Facial Soap | 5-10% | Gentle, nourishing, ideal for sensitive skin |
| Body Soap | 5-8% | Balanced cleansing and moisturizing |
| Shampoo Bars | 0-3% | Focus on cleansing scalp, less residue |
| Laundry/Utility Soap | 0-1% | Maximum cleansing power, no extra oils |
Choosing the right superfat percentage is a crucial step in soap making, allowing artisans to customize their products for specific skin types and uses.
