Modifying Your Liquid Soap Formula

You're interested in adding Glycerin and Natural Essential Oil to your liquid soap formula based on the Sulfate Free Shampoo Base. This is a great way to customize your soap!

The original formula is:

• Sulfate Free Shampoo Base (pH 7, Clear, Foaming): 35%
• Distilled Water: 64%
• Preservative: 1%
• Total: 100%

When adding new ingredients like Glycerin and Essential Oil, you need to reduce the percentage of other ingredients to keep the total at 100%.

Adding Glycerin

Glycerin acts as a humectant, helping to attract and retain moisture, making the skin feel softer. While Glycerin can be used at high percentages, for a wash-off product like liquid soap, a typical and effective usage rate is between 1-5%. Adding 99.5% as you mentioned would be far too high and would likely result in a very sticky or unusable product.

Adding Natural Essential Oil

Natural Essential Oils, such as Ylang Ylang Oil, are used for fragrance. They are very concentrated and should be used in small amounts, typically between 0.1-0.5% of the total formula. Using too much can cause skin irritation.

Suggested Adjusted Formula Example

To incorporate Glycerin and Essential Oil, you can reduce the amount of Distilled Water. Here is an example using recommended percentages for the added ingredients:

• Sulfate Free Shampoo Base (pH 7, Clear, Foaming): 35%
• Glycerin (USP/Food Grade): 3%
• Natural Essential Oil (Ylang Ylang Oil): 0.3%
• Preservative (e.g., Mild Preserved™ COS): 1%
• Distilled Water: 100% - 35% - 3% - 0.3% - 1% = 60.7%

New Formula:

• Sulfate Free Shampoo Base (pH 7, Clear, Foaming): 35%
• Distilled Water: 60.7%
• Glycerin (USP/Food Grade): 3%
• Preservative (e.g., Mild Preserved™ COS): 1%
• Natural Essential Oil (Ylang Ylang Oil): 0.3%
• Total: 100%

General Mixing Steps

1. Measure the Distilled Water.
2. Add Glycerin to the water and stir until fully dissolved.
3. Slowly add the Sulfate Free Shampoo Base, stirring gently to avoid excessive foaming. Continue stirring until the mixture is uniform.
4. Add the Preservative and stir to combine.
5. Add the Natural Essential Oil and stir gently until dispersed. The oil may cause slight cloudiness.

Important Considerations

• Ensure the preservative you choose is suitable for the product's pH range (6.5-7.5 for this base). Mild Preserved™ COS is an example of a broad-spectrum preservative suitable for pH 2-8.
• Always start with a low percentage of essential oil and adjust to your preferred scent strength, staying within safe usage guidelines.
• Test the final product for stability, clarity, viscosity, and skin feel.