A question for the lab guy's

I manufacture a soft shaving soap from 100% KOH and is super fatted <10%

It has been toxicologist tested for the EU market and was given a 12 month shelve life.

Recently I had a customer who reported that his soap had separated just within the 12 month period. At first I thought it may of been bad storage conditions, heat damage.

But after asking him lots of questions I know believe that the soap became contaminated.

The soap intended use is to remove some of the soap product from it's container and with a wet brush, lather the soap in a separate shaving mug/bowl.

My customer was lathering straight from the products container. He then had a period of not using it and stored it in a cupboard with the lid on. After a couple of months he opens the tub to discover the separation. He also reported no bad smell. But this got me thinking, is it possible to contaminate the soap.

The soap formula has no preservative because it's expected PH level is 9.5-10.5 which inhibits growth. But am I right in thinking that adding tap water would reduce the PH level, introduce minerals for bacteria to thrive and if the brush is not clean introduce bacteria?

I have discontinued the shaving soap until I feel happy that the product is safe to use.

If contamination is the case then I need to make some obvious changes to this product.

Any help with this would be greatly received.


  • BelassiBelassi Member, PCF student
    edited June 2016
    Yes, almost certainly that is what happened. You have free oil and water, once the pH drops, bacteria can begin to grow. Rather than adding a preservative you might think about changing the packaging system so that the customer uses it as directed.
    Cosmetic Brand Creation. Concept to name to IMPI search to logo and brand registration. In-house graphic design inc. Pantone specs. Cosmetic label and box design & graphics.
  • Thank you for your speedy reply. Yes that was my thought too Belassi, a change in packaging, reduced neck with a clear and easy to read usage instructions.

    I don't like the idea of using mixed preservatives and a chelating agent, kind of goes against the idea behind having the product.

  • BobzchemistBobzchemist Member, PCF student
    Either that, or boost the pH up over 12.0. You'd probably have to change the superfat to using non-saponifiable emollients if you do that, though.
    Robert Zonis, Sr. Formulation Chemist, Beaumont Products "All opinions and comments expressed are my own, have no relation to Beaumont Products, are fully copyrighted, and may not be used without written permission."
  • Thank you Bob, why didn't I see this myself. Yes that makes perfect sense now you pointed this out.

  • Just curious, did you perform any form of Challenge testing (PET)? Changing the packaging is a good step, but it would be better to have a reliably self preserving formula. Consumers can do a lot to a package and that liability is not worth skipping a PET. I have had formulas fail PET at a pH of above 10, its uncommon, but can happen.
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