Lotion Separation Issue During Homemade Formulation

Question

I am trying to make lotion myself based on research, but when I emulsified it, it seems like the ingredients did not mix well. The total batch size is 250g. The ingredients are as follows:

Distilled Water 71% (177.5g)
Glycerin 2% (5g)
Extra Virgin Olive Oil 8% (20g)
Stearic Acid 3% (7.5g)
Poly sugar mulse d9 (Sorbitan Oleate DecylGlucoside Crosspolymer) 2% (5g)
Chamomile Extract 1% (2.5g)
Arnica Extract 3% (7.5g)
Seaweed Extract 2% (5g)
Aloe Vera Extract (liquid) 3% (7.5g)
Vitamin E Acetate 3% (7.5g)
Essential Oil 1% (2.5g)
Mild Preservative Eco (Ethylhexylglycerin and Propanediol) 1% (2.5g)

The process I followed is:

Heat Distilled Water to 70-80°C, remove from heat, and add Glycerin.
Heat Extra Virgin Olive Oil, Stearic Acid, and Poly sugar mulse d9 to 70-80°C.
Combine the water from step 1 with the oil phase from step 2 and emulsify until the temperature is below 40°C (it mixed into something like milky water, not thick lotion).
Weigh and add the extracts from items 6-10 and emulsify until combined.
At this point, it started separating into a milky water part and a thicker, floating part.
Add the essential oil and preservative.
The final result is a thick part floating on top and a milky water part below. What step did I do incorrectly? Thank you.

MySkinRecipes Expert · Accepted Answer

Lotion Separation Issue and Solution

Based on the ingredients and process you described, the separation likely occurred because the water-based extracts (Chamomile, Arnica, Seaweed, Aloe Vera) and the oil-soluble Vitamin E Acetate were added after the main emulsion had formed and started cooling, but before it was fully stable or thickened. Adding these ingredients at lower temperatures can disrupt the emulsion, especially with a relatively high percentage of extracts (9% total) and the oil-soluble Vitamin E Acetate (3%).

Here’s a suggested revised process to help prevent separation:

Combine Water Phase: Combine Distilled Water and Glycerin. Heat this phase to 70-80°C.
Combine Oil Phase: In a separate container, combine Extra Virgin Olive Oil, Stearic Acid, Poly sugar mulse d9, and Vitamin E Acetate. Heat this phase to 70-80°C. Ensure both the water and oil phases are at approximately the same temperature before mixing.
Emulsify: Slowly add the hot Oil Phase to the hot Water Phase while mixing continuously with high shear (e.g., using a stick blender) for several minutes. Continue mixing as the emulsion cools.
Add Water-Based Actives: Once the temperature drops below 40°C and the emulsion has started to thicken, add the Chamomile Extract, Arnica Extract, Seaweed Extract, and Aloe Vera Extract. Mix well to ensure they are fully incorporated.
Add Preservative and Fragrance: Once the temperature is suitable for your preservative (check the supplier's recommendation, usually below 40°C or 30°C), add the Mild Preservative Eco (containing Ethylhexylglycerin and Propanediol) and Essential Oil. Mix thoroughly.
Cool Down: Continue mixing occasionally until the lotion reaches room temperature.

Additional Tip: The combination of Poly sugar mulse d9 and Stearic Acid might benefit from a water-phase thickener (like a gum or carbomer) to increase the viscosity of the water phase. This can help stabilize the emulsion and prevent separation, especially when incorporating a high percentage of water-based extracts.