Home Cosmetic Science Talk Formulating Anhydrous Sugar Scrub (question regarding heat stability)

  • Anhydrous Sugar Scrub (question regarding heat stability)

    Posted by Jennyk on March 19, 2021 at 3:04 pm

    Hello fellow formulators!

    I’ve been making the anhydrous sugar scrub below for a while now and I absolutely love the consistency and feel of it, but I’ve failed multiple times at getting it to stay solid during shipping when the temperature is above 90 degrees.

    Assuming I’m insulating my shipments well, and using ice packs during extreme heat, is there anything else you’d recommend to prevent this from happening? I realize it’s inevitable that the formula will soften, but I’m trying to prevent situations where the sugar separates from the oil, causing the oil to leak outside of the jar. 

    Would I be better off increasing the emulsifier, or adding stearic acid? I’m hoping to not change the consistency of the formula when it’s at room temp, and I’m concerned that both of these solutions will do just that.

    My most recent trial was to replace the coconut oil (melting point 74 degrees) with “high melt coconut oil” (92 degrees) since that seems to be the weakest link in this formula, but upon testing it appears to not have done much.

    Any suggestions? Thanks so much for whatever advice you can offer!

    60% sugar
    11% high-melt coconut oil
    11% shea butter
    11% rice bran oil
    4% Emulsifying wax (cetearyl alcohol/ceteareth-20)
    1% vitamin E
    1% essential oil
    1% Germail Plus

    Anca_Formulator replied 2 years, 10 months ago 5 Members · 4 Replies
  • 4 Replies
  • bill_toge

    March 20, 2021 at 9:27 pm

    hydrogenated castor oil / castor wax (m.p. 70-80 °C / 158-176 °F) acts as a gelling agent and generally improves the thermal stability of oil-based products

  • EVchem

    March 22, 2021 at 4:23 pm

    I’m a fan of adding a little aerosil (silica) but it can potentially change texture/feel if you go too high

  • smok

    March 22, 2021 at 7:15 pm
    why using Emulsifying wax (cetearyl alcohol/ceteareth-20)?
  • Anca_Formulator

    April 18, 2021 at 1:42 am

    You can add a butter with a higher melting point, such as cocoa butter. Or you can add 5 % of fatty alcohols with higher melting points, like cetyl or behenyl alcohol (158 F) also helps. If not enough, increase percentage gradually. Also Cera Bellina works.Then there is Softisan 378 (Glyceryl Stearate (and) Stearyl Alcohol (and) Polyglyceryl-2 Stearate) which also works. Good luck!

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