Understanding Color Change in Your Oil Soap with Citrus Fragrance

The color change you observed in your Oil Soap after adding a Citrus fragrance, specifically mentioning Citral, is a common issue related to the stability of fragrance components in certain bases, especially those with a high or low pH.

Why the Color Changed

Fragrance ingredients, like Citral, can be sensitive to the pH environment of the product they are added to. While the overall pH of your soap base doesn't change significantly upon adding the fragrance, the existing pH level can cause chemical reactions within the fragrance itself. This reaction leads to the degradation of certain fragrance molecules, resulting in a change in color over time, often progressing from yellow to darker shades like orange, red, and eventually black, as you described.

Is it Safe to Use?

The color change primarily indicates that the fragrance components have degraded. While this degradation affects the scent and appearance of the soap, it does not necessarily make the product unsafe for use. However, if you notice any changes in texture, consistency, or experience skin irritation, you should discontinue use.

How to Prevent Color Change

To prevent this issue when using citrus or other potentially sensitive fragrances in soap bases:

• Choose pH-Stable Fragrances: Look for fragrances specifically designed and tested for stability in soap or high/low pH environments. Suppliers often provide information on the recommended applications and stability of their fragrances.
• Test Stability: Always perform a small-scale test by adding the fragrance to your soap base and observing it over time (days to weeks) under different conditions (e.g., room temperature, elevated temperature) before making a large batch.
• Consider Alternative Scents: If a specific citrus fragrance consistently causes discoloration, you may need to choose a different fragrance that offers a similar scent profile but uses more stable components.

Using fragrances specifically formulated for the type of base you are working with is key to avoiding stability issues like color change.