Home Cosmetic Science Talk Formulating Hair Preservative not working with soapwort shampoo

  • Preservative not working with soapwort shampoo

    Posted by tamicet on June 16, 2017 at 5:25 am

    Hi, I’m new here so forgive me if I started this discussion in the wrong category. First of all I’d like to say I find Chemists Corner extremely helpful, educational and informative so a big thank you for that.
    I am posting here because I can’t find any answers to my dilemma elsewhere on the internet and I’m hoping that someone can give me some advice.
    I make a natural shampoo out of soapwort to try to combat dry patches on my scalp as everything thing else I have tried does not seem to work. The recipe is as follows:
    I boiled 2 cups of distilled water with 2 tablespoons each of dried soapwort root, dried marshmallow root and white willow bark. When the mixture has simmered down to about 1 cup, I strained it, poured it into a foaming bottle sprayed earlier with 99% Isopropyl Alcohol and let it cool down to below 50C. I then added Liquid Germall Plus at 0.5%.
    The first time I made it, I didn’t have a preservative on hand yet and it molded within 1 week. However this time with LGP, after 18 days it hadn’t molded but I had decided to test it using Microcount Duo by Schuelke to see if the preservative was working. 24 hours after I smeared both sides of the dipslide with a cotton bud soaked with the shampoo, the total plate count side was completely covered with small red spots which, from what I could understand, means that it is full of bacteria although the yeast and mold side seems clear.
    I kept the bottle of shampoo in the shower.
    I understand that botanicals are hard to preserve, however I did not expect that after 18 days (probably even earlier) bacteria to grow with the inclusion of LGP at the maximum recommended rate.
    So I suppose my question is, am I doing something wrong? If the preservative is the problem, is there a preservative someone can recommend for this recipe please, keeping in mind that I live in a European Union country?
    Thanks in advance for any advice!

    tamicet replied 6 years, 9 months ago 4 Members · 8 Replies
  • 8 Replies

    June 16, 2017 at 3:25 pm

    what is  the Ph of your product?

  • belassi

    June 16, 2017 at 4:45 pm

    So you appear to be assuming that synthetic surfactants are the cause of your problem. That’s quite possible if you are relying on shop bought products, 95% or more of them are based on SLS/SLES. May I suggest a better approach would be to formulate using non-sulphate based synthetics such as cocoamidopropyl betaine, sodium cocoamphoacetate and a thickener, or buy a blend eg. Iselux.

  • tamicet

    June 17, 2017 at 6:56 pm

    Thanks for answering!

    DRBOB@VERDIENT.BIZ: to tell you the truth I hadn’t thought to check the ph at that time. I’ll make a smaller batch and test it.

    Belassi: yes the dried herbs and botanicals are all shop bought. I will try your suggestion. Thanks for your help!

  • belassi

    June 17, 2017 at 11:34 pm

    What I was implying is that your scalp problem may improve if you formulate or buy a non-sulphate blend of shampoo. You might like to incorporate natural substances, for instance I have tried making shampoo out of coffee and beer with success.

  • johnb

    June 18, 2017 at 8:38 am

    24 hours after I smeared both sides of the dipslide with a cotton bud soaked with the shampoo

    Was the cotton bud sterile?

  • tamicet

    June 21, 2017 at 6:12 pm

    Belassi: Thanks again…beer or coffee sound enticing in a shampoo! I make a gentle cold process soap with beer but it hadn’t crossed my mind to use it in a shampoo formula.

    johnb: as far as I know the cotton bud was sterile because I used another cotton bud from the same packet to spread a sample of my homemade deodorant on the dip-slide of another Microcount Duo test vial and it resulted clear.

  • johnb

    June 22, 2017 at 7:49 am

    Cotton buds are not sterile, nor are they designed to be. To obtain any meaningful information it is necessary to have all equipment sterile. Cotton or rayon swabs for bacteriology are readily obtainable from laboratory supply houses, even Amazon https://www.amazon.co.uk/neoLab-2-1019-Sterile-Cotton-Handle/dp/B01AWE8R26/ref=sr_1_15?s=industrial&ie=UTF8&qid=1498117544&sr=1-15&keywords=swabs
    (OK that is Amazon UK but I’m pretty sure that similar things are available anywhere).

    The reason you obtained a “clear” result from your deodorant is most likely because these products are usually designed to be antimicrobial with an immediate activity. Preservative materials often take some time to act so, presented with a fresh source of infection (your cotton bud), it is overwhelmed resulting in apparent lack of activity of the preservative.

  • tamicet

    June 30, 2017 at 6:52 am

    Hi johnb. Thanks for your advice. Will buy sterile swabs and try the tests again.

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