Addressing Rancid Smell in Lotion

Subject: Addressing Rancid Smell in Lotion

Hello,

Regarding the issue with your lotion sometimes developing a rancid or spoiled smell, even with a preservative, this inconsistency can be frustrating. Based on your formulation and the staff's feedback, here are the potential causes and suggested solutions:

1. Fragrance Incompatibility or Instability: Fragrances are complex mixtures. Sometimes, components in the fragrance can react with other ingredients in the formula over time, leading to off-odors. The staff noted that if the fragrance is inconsistent between batches, this could explain why the smell doesn't occur every time.

   • Solution: The staff recommended testing your formula with and without the fragrance to determine if the fragrance is the source of the problem.

2. High Concentration of Emulsifier (Satin Cream Maker): You are using Satin Cream Maker at a relatively high percentage (12.57%). While this emulsifier is effective, using it at a high concentration can potentially affect the overall stability of the formulation or interact with other ingredients, which might contribute to odor development. It also increases the formula cost unnecessarily.

   • Solution: The staff suggested considering a change in the emulsifier system to Butter Cream Maker (Product ID 1041) combined with AnyGel (Product ID 1282) if you can incorporate heat into your mixing process. This alternative system might offer better stability and cost-effectiveness.

3. Preservative Concentration: Although you are using a preservative (Mild Preserved Eco), the concentration might be slightly low for this complex formulation, especially given the presence of natural ingredients like Natto Gum and shea butter water, which can be prone to microbial growth if not adequately preserved.

   • Solution: The staff recommended increasing the concentration of Mild Preserved Eco (Product ID 1001) to 1.0% to ensure sufficient preservation.

Summary of Recommendations:

• Primary Test: Follow the staff's suggestion to make two batches: one with your current formula including the preservative but without fragrance, and another with the full formula (including preservative and fragrance). Observe both batches over time to see if the off-odor develops only in the batch with fragrance.
• Adjust Preservative: Increase the concentration of Mild Preserved Eco (Product ID 1001) to 1.0% in future batches.
• Consider Emulsifier Change: If the above steps don't fully resolve the issue, or if you are open to using heat, consider switching the emulsifier system to Butter Cream Maker (Product ID 1041) + AnyGel (Product ID 1282) as suggested by the staff, adjusting the percentages as needed for the new system.

By systematically testing and adjusting these factors, you should be able to identify the cause of the inconsistent smell and achieve a more stable lotion.

Relevant Product IDs from your formula: 74, 116, 145, 737, 1019, 403, 654, 128, 78, 247, 1001.