Body Salt Scrub Formulation Issues and Solutions

It appears you are experiencing two main issues with your body salt scrub: oil separation and color change (yellowing). These are common challenges with salt scrubs due to the high salt content and the nature of the ingredients.

Here are some suggestions to help improve the stability and prevent these issues:

Preventing Oil Separation

The separation of oil from the salt is likely due to the density difference between the oil and the water/liquid soap phase, and the high percentage of salt which is a heavy solid. Your current emulsifier (ewax) and thickener (stearic acid) may not be sufficient to create a stable suspension for such a high load of salt.

• Use a Suspending Agent: Incorporating a suspending agent can help keep the salt particles evenly dispersed throughout the scrub and prevent the oil from separating.
  • Xanthan Gum is a very effective natural gum that can create a gel network to suspend particles. It is easy to use and works well in formulations with high salt content. You can add it to the water phase before mixing with the oil phase. A typical usage rate is 0.1-2%.

Preventing Color Change (Yellowing)

The yellowing is likely caused by oxidation of the oils or other components in your formulation. While you are using BHT, it might not be sufficient, or the type of oil used might be particularly prone to oxidation.

• Add a Chelating Agent: Metal ions present in water (especially if not distilled or deionized) can catalyze oxidation reactions, leading to discoloration.
  • Disodium EDTA is a chelating agent that binds to these metal ions, preventing them from causing instability and discoloration. It is typically used at a low concentration (0.1-0.2%) in the water phase.
• Enhance Antioxidant Protection: You can boost the antioxidant protection in your formula.
  • Vitamin E (dl-alpha tocopherol) is a fat-soluble antioxidant that is very effective at protecting oils from oxidation. It works synergistically with BHT. Add it to your oil phase.
  • Ensure the oil you are using is fresh and has good oxidative stability. Some natural oils are more prone to oxidation than others.
  • Consider the fragrance used, as some fragrance components can also cause discoloration over time, especially when exposed to light or air.

By adding a suspending agent like Xanthan Gum and enhancing antioxidant/chelating protection with ingredients like Disodium EDTA and Vitamin E, you should be able to significantly improve the stability and appearance of your body salt scrub over time.