You didn’t use emulsifying wax in a formulation that called for emulsifying wax.
You didn’t use a complete emulsifying wax.
Some suppliers sell ingredients they call “emulsifying wax” that may have some emulsifying properties but require co-emulsifiers and/or stabilizers to work. These so-called “emulsifying waxes” won’t work in my lotion recipes on their own. Make sure you’re reading product descriptions and reviews, as well as looking at the INCI for the ingredient. If the INCI is just one ingredient, be wary. For instance, an INCI of just “Cetearyl Alcohol” would not be an emulsifier, but “Cetearyl Alcohol (and) Polysorbate 60” is—that’s Emulsifying Wax NF.
You didn’t use enough emulsifier.
Different emulsifying waxes have different recommended usage rates, but most of the emulsifying waxes we use work well at 20–25% of the oil phase. To determine this, add up everything in your oil phase (including the emulsifying wax) and then divide the amount of emulsifying wax by that total. To take this formulation as an example; the oil phase is 13%, and there is 3% emulsifying wax. 3 ÷ 13 = 23%. That’s within the 20–25% range.
As always, know your ingredients, as this isn’t a universal rule. Compare your emulsifier usage rate with what your suppliers recommend and what you see in sample formulations from suppliers and manufacturers; if you’re using the emulsifier at a drastically lower rate than recommended, that might be your problem.
You didn’t blend/stir the lotion enough.
Some emulsifying waxes require somewhat constant whisking until the lotion has cooled to maintain the emulsion, and some really need high-shear blending in order to form stable emulsions. Know your ingredients!
Your cool down phase was too large.
If your cool down phase is 10% or larger, that can destabilize emulsions.
Something about your formulation conflicts with your emulsifier (or something else in the formulation).
Check on charge, pH, oil phase size, and electrolyte content to start with. Once you figure out where the conflict is, remove it and see if that fixes the problem.
You altered the proportions of the formulation enough to break the formulation.
Most emulsifying waxes work with relatively specific oil to water ratios, and changing those ratios too much can break the emulsion. This can happen by attempting to convert a recipe written in weight to volume measurements.
The preservative you added broke the emulsion.
Optiphen Plus is is one preservative that can de-stabilize emulsions.
Your formulation was too thin for the emulsifier.
The thinner an emulsion is, the more likely it is to split. How thin is “too thin” will vary with the emulsifier. Adding a bit of a gum or other gelling ingredient can help stabilize the emulsion.
Posted in: Troubleshooting & Adjusting