Glycerin vs Glycerin? - Cosmetic Science Talk

Glycerin vs Glycerin?

edited November 2013 in Formulating
I made a formula using some glycerin that I got from from Amazon and liked how it turned out...
I then made the same formula with glycerin from Bulk Apothecary and it looked the same but didn't last as long. Its shelf life is less.

I'm guessing there's some variation between the 2 glycerins. Does anyone know how you distinguish between different types of glycerin? They both say "Vegetable KOSHER USP FOOD GRADE."

Comments

  • If USP grade then it means food grade, it's beyond comprehension why you are getting this anomaly. Maybe some processing difference from different suppliers. 
  • I'm not sure what you mean as "didn't last as long".  What happened to the product?  Was it microbial contamination?  That is a likely explanation.  One source produced the glycerin under proper conditions and the other didn't.
  • what's the strength?

    USP is usually 99.9% (ish) , there are other grades out there that are as low as 85% - perfectly good as food grade, but the extra water may cause a problem.

    UK based, Over 20 years in Toiletries, now on the dark side, I&I cleaning products
  • Perry: the gel dried out, got crusty etc for the one glycerin in about 6 months; the other one stayed moist and true to its original gel consistency for 18 months and counting.

    milliachmeist & Duncan: The "good" glycerin has a COA available, http://www.essentialdepot.com/msds/coa glycerin kosher food.pdf which says 99.84% purity. I am still waiting to hear back from the other supplier for purity/strength - maybe that will be the explanation?
  • On another note about glycerin, does anyone know of a supplier that carries Glycerin RM  w/o sulfate impurities? All the ones that I know of are w/ sulfate impurities. 
  • The test for sulfate is a Pharmacopoeial limit requirement, pretty sure anyone will leave it off the C of A if you ask nicely.  ;) 
  • @alchemist Thank you for the info! =)
  • There is Glycerin (99.5%) from Cremer Oleo (Supplier):
    http://cremeroleo.com
    Reference: Formulary Nature I Classic - Edition 2015 - drstraetmans
  • This sounds like more of a packaging issue than a Glycerin issue if your gel dried out ... I suspect the seal was not tight on one allowing for evaporative loss of water over some period of time.  Glycerin is not volatile.  All depends on what else is in your formula.
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    Provides Formulation Development and Lab-Scale Contract Manufacturing Services.  See website for details www.desertinbloomcosmeticslab.com

  • Mark, this thread has been resurrected from 2013 - I don't think the originator cares very much now.

    I was caught out this morning by the same overkeen newbie.
  • Ahhh ... didn't even notice that.  Thx.
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    Provides Formulation Development and Lab-Scale Contract Manufacturing Services.  See website for details www.desertinbloomcosmeticslab.com

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