Surfactants in Traditional Bar Soap

You've encountered a common issue when trying to add surfactants like Coco Betaine, Sodium lauroyl glutamate, and Lauryl glucoside to traditional bar soap made via saponification with NaOH. The separation you observed is expected because these types of surfactants are generally not compatible with the high pH environment of traditional bar soap.

Traditional bar soap made with NaOH typically has a pH ranging from 9 to 11. Many surfactants, including the ones you mentioned, are designed to be stable and effective in lower pH conditions, such as those found in liquid soaps, shampoos, or synthetic detergent (syndet) bars (which often have a skin-friendly pH around 5.5).

When you add surfactants formulated for lower pH into a high-pH traditional soap base, they can become unstable, lose their properties, or react in ways that cause the mixture to separate, as you experienced.

Therefore:

• Can these specific surfactants be used in traditional NaOH bar soap? Generally, no, due to the significant difference in pH requirements.
• How to fix the separation? It is difficult or impossible to effectively incorporate these specific surfactants into a finished traditional bar soap base because the pH incompatibility is a fundamental issue.

If you want to improve the moisture and foam of your traditional bar soap, consider these methods that are compatible with the saponification process:

• Superfatting: Adjust your recipe calculation to leave a small percentage of oils unsaponified. This "free oil" remains in the finished soap and contributes to a more moisturizing feel.
• Adjusting Oil Blend: The types of oils you use in your saponification recipe greatly influence the lather and feel of the soap. Oils like coconut oil and palm kernel oil contribute to bubbly lather, while oils like olive oil or shea butter provide a creamier lather and conditioning properties. Experimenting with different oil combinations is key to achieving desired foam and moisture.

If your goal is specifically to use surfactants like Coco Betaine, Sodium lauroyl glutamate, or Lauryl glucoside, you would need to work with a different type of soap base, such as a synthetic detergent (syndet) bar base or a low-pH soap base designed to be compatible with these additives.