Potential Causes of Separation

1. Inaccurate Weighing (as advised by cosmeceutical7): Making small batches of only 20 grams makes it very difficult to accurately weigh small percentages of ingredients, such as 1% Light cream maker (which is only 0.2 grams) or the total 1% Hyaluronic Acid powders (0.2 grams). If the amount of Light cream maker, which acts as the emulsifier (the ingredient that helps oil and water mix), is insufficient or inconsistent between batches, the formula will not be stable and will easily separate. This is the most likely primary cause of inconsistency in small batches.
2. Dissolution of Hyaluronic Acid: Powdered Hyaluronic Acid (both Standard and Nano) requires time and/or energy to fully dissolve in water. The product description for Hyaluronic Acid (Standard Molecule) indicates that if you don't have a blender, you need shaking and refrigeration for at least 3 hours to dissolve completely, or high-speed blending (>1000 rpm). If the powders are not fully dissolved before combining the phases, the viscosity of the water phase may be inconsistent, affecting emulsion stability.
3. Technique and Order of Mixing: While adding the water phase to the oil phase while mixing is a valid method for creating emulsions, its effectiveness depends on the specific Light cream maker used, the mixing energy (speed and duration), and the temperature. If your Cream maker requires high shear mixing or a specific temperature range for emulsification, manual mixing or inadequate blending might result in incomplete emulsification.
4. Addition of Centella Asiatica Extract: The product description for Centella Asiatica Extract (Madecassoside 90%) recommends adding it in the final step (into the finished gel or cream) and avoiding heat. Adding Centella to the water phase before emulsification might affect the stability of the water phase or, if the Cream maker is sensitive to certain components in the extract, could interfere with the emulsification process.
5. Ingredient Storage: Product information for Hyaluronic Acid (Standard Molecule), Hyaluronic Acid (Nano Molecule, 800daltons), Hyaluronic Acid (Nano Molecule, 2000daltons), and Centella Asiatica Extract (Madecassoside 90%) recommends refrigeration for long-term storage to maintain quality and efficacy. Phenoxyethanol, Moringa Oil, Jojoba Oil, and Grape Seed Oil can be stored at room temperature but should be kept away from heat, sunlight, and air. Improper storage can degrade ingredient quality over time, potentially contributing to formula instability, although weighing accuracy and emulsification technique are more probable causes for the immediate separation issues.

Recommendations for Improvement

1. Improve Weighing Accuracy: If possible, increase the batch size to make weighing small percentages more accurate, or use a highly precise scale.
2. Check Cream Maker Instructions: If you know the specific name of the Light cream maker, carefully review the supplier's instructions for usage, including required temperature, addition phase, and mixing method/energy.
3. Ensure Hyaluronic Acid Dissolution: Make sure the Hyaluronic Acid powders are fully dissolved in the distilled water and the water phase has formed a clear gel before combining it with the oil phase. Allow sufficient time for dissolution, using refrigeration or blending as recommended by the product instructions.
4. Adjust Centella Addition: Try adding the Centella Asiatica Extract in the final step, after the emulsion has formed and cooled down, to avoid potential interference with the emulsification process.
5. Maintain Consistent Mixing: Aim for consistent mixing speed and duration in each batch. If using a blender, ensure it provides sufficient shear for emulsification.
6. Proper Ingredient Storage: Store ingredients according to the supplier's recommendations, especially Hyaluronic Acid and Centella Asiatica Extract, which benefit from refrigeration for long-term stability.

The inconsistency and separation in your small-batch emulsion are most likely due to variations in the amount of emulsifier caused by weighing inaccuracies. Improving weighing precision and ensuring proper emulsification technique based on your specific Cream maker are key to achieving stable results.

Hope this helps!