Dear Valerie: I am considering some different waxes for a project and I noticed some of the wax documents disclose drop point (and no melting point), while other waxes note melting point (but no drop point). Which reading should I rely on for choosing a wax? —Wax N. Poetic

Dear Wax, 

The first lab machine I recall using in college, aside from a scale, was a melting point apparatus. Stuffing the capillary tubes and watching the warm glow of the ancient heating elements was really satisfying. I particularly loved snapping the capillary tubes after taking them out. It was pure lab ASMR. I’ve thought about buying a melting point device for my lab to fulfill that nostalgic hole on my countertop but it’s more cost effective to rely on what the raw material manufacturer tells me.

The difference between melt point and drop point is actually a pretty important one, and I wouldn’t know it without going through my wax obsession phase (and asking Koster Keunen a million questions.)

Simply put, melting point measures the temperature at which the wax goes through a phase transition, from solid to liquid. Drop point is the temperature at which the wax’s crystalline structure deteriorates and starts to flow. It’s not the temperature where the wax goes from a liquid to a solid.

Melting point not only contributes to hardness of a product, but it will also guide you in your formula process as it tells you how hot you need to heat the wax/oil phase up. If the melting point of the wax says 40-55ºC, your oil phase should be heated up to at least 55ºC. This ensures everything is melted and prior crystal structure is erased, which allows for uniform recrystallization on cooling. Melting point is usually noted as a range, from when a material first starts to melt until it’s fully melted. 

Drop point is an interesting metric because it informs you of the stability of a wax-based product. If a wax has a drop point of 60ºC, that means at 60ºC the wax can no longer stay in its form and will start to flow, get mushy, etc. This is especially an important metric in anhydrous stick formulas because once they’re made into a stick, you don’t want them to lose their structure. Unless you’re a fan of taking out a lip balm from your pocket and having it deteriorate all over your lips or leak out of the component.

Combining low drop point waxes with high drop point waxes gives the final wax-based product its own drop point, which should be tested for. If you want to increase your drop point, it’s not as simple as increasing your high drop point waxes. Doing so may negatively impact your formula aesthetics. Play with different polarities of oils to modify the gel network, try different ratios, try different waxes or—as someone at Koster Keunen once told me in a true Portlandia “put a bird on it” moment— just throw a little polyhydroxystearic acid in.

You can read more Dear Valerie here.

Valerie George

askvalerie@icloud.com

Valerie George is a cosmetic chemist, science communicator, educator, leader, and avid proponent of transparency in the beauty industry. She works on the latest research in hair color and hair care at her company, Simply Formulas, and is the co-host of The Beauty Brains podcast. You can find her on Instagram at @cosmetic_chemist or showcasing her favorite ingredients to small brands and home formulators at simply-ingredients.com