Home Cosmetic Science Talk Formulating Skin Soap Odor: Prominent Coconut Oil Odor

  • Soap Odor: Prominent Coconut Oil Odor

    Posted by Aijalon on March 11, 2016 at 8:08 am

    Greetings to all!

    I am working in a Soap Manufacturing Facility wherein we use the cold process in producing our soap products with Refined Deodorized Coconut Oil as our main fatty acid. For quite sometime now, we have incidences where our soaps (around 3-4 months old and beyond) produce a bad prominent coconut oil odor. 
    What could possibly be the reason for this? My root cause analysis lead me to believe that it is the storage conditions (high temperature and humidity) that caused our soaps to release the odor. If my analysis is right, how can I possibly resolve the problem given that the country I live in is tropical with high to elevated environmental conditions?
    If it’s not the environmental conditions, maybe the processing? Raw materials?
    Thank you hearing me out. 
    David08848 replied 8 years, 2 months ago 4 Members · 10 Replies
  • 10 Replies
  • belassi

    Member
    March 11, 2016 at 4:28 pm

    It sounds as if one or more of the oils you are using is going rancid at that storage time. It’s important to use the correct blend of oils. If you will tell us what the blend is, I will be able to comment further. It is not the coconut oil, unless the oil you’re buying is impure or old.

  • Bobzchemist

    Member
    March 11, 2016 at 6:17 pm

    I agree with the @Belassi on rancidity being the cause. The easiest way to fix it is to use BHT, either mixed into your oils as soon as you get them, or mixed into your soap, or both.

  • Aijalon

    Member
    March 11, 2016 at 11:55 pm

    Thank you @Belassi and @Bobzchemist for your response. 

    We only use Refined Deodorized Coconut Oil in our Soaps. As for the oil rancidity, we perform quality control tests in our Oil before we use it in our production. Also, before we release the products out from our Warehouse, we perform organoleptic evaluation in our soap bars. 
    It is only after a few months after product release that the incidences occur. 
    By the way, our packaging is just a unit box (gloss 80). Our soaps are directly placed inside the box. No plastic or wax paper used.
    I will read more on BHT for now. Thank you!
  • belassi

    Member
    March 12, 2016 at 3:24 pm

    If you are using only coconut oil then you must be using a high superfat percentage - at least ten percent, probably more - otherwise your soap will be horribly drying to the skin. With that percentage of unreacted oil, that could easily be responsible.

    It would be better to change your formula. Palm oil makes a good soap and is very stable and not prone to go rancid, also gives good hardness and whiteness. A suggested blend would be something like 40% coconut, 40% palm, 20% high oleic oil (eg modified rapeseed) similar to olive oil, with a 4% superfat. And also add BHT as Bob said.
  • Bobzchemist

    Member
    March 12, 2016 at 7:40 pm
    I’ve go to ask - if you didn’t want our advice, why did you waste our time asking questions?

    You really need to talk to/hire a consulting chemist if you don’t believe us. Oxidative stability/rancidity is not something that can possibly be detected in your pre-production testing, since the reaction is clearly hapening during several months post-production.

  • Aijalon

    Member
    March 13, 2016 at 3:16 am

    @Belassi, Yes, our soap is drying to the skin but our consumers seem to like the drying effect. Though, I’ll make sample batches of your suggested blend with the addition of BHT. 

    @Bobzchemist, I seriously want your advice and by no means want to waste your time. Forgive me if I offended you in any way. I misunderstood what you meant by oil rancidity. I was thinking of the raw oil being rancid before it is saponified. Also, I’ve already read more on BHT. I guess I’ll have to dose our products with it.
    Thank you!  
  • Aijalon

    Member
    March 15, 2016 at 1:23 am

    Greetings to all!

    I’ll be dosing the oil we use for our soaps with BHT. I looked into its recommended dosage and found out that it should be around 0.01% - 0.1%. I was thinking of using 0.05%. For those who have experience using BHT, is this dosage reasonable? 
    I know I need to do experimental studies to validate this assumption (which I will do as soon as I can get a hand on BHT). For now, I would like to get opinions/theories regarding this.
    Thank you very much! 
  • belassi

    Member
    March 15, 2016 at 2:00 am

    I had a lot of problems when we began making soap 5 years ago. Most of our problems stemmed from the fact that we weren’t making enough to be able to buy the proper oils in industrial sized amounts, and so we used unsuitable oils.

    By unsuitable, I mean any oil containing say linoleic acid. Corn oil, sunflower oil, soya oil … these oils that you find in the supermarket do not make good soap. It “sweats” under high humidity and temperatures. It goes rancid in 4 months.
    The three basic oils to use that do not go rancid, are coconut, palm, and olive. Coconut for bubbles and cleansing, palm for creamy lather, hardness, whiteness, and stability; and olive for creamy lather, stability, and skin conditioning effect.
    Too much coconut strips the skin of its natural oils and can cause problems.
    Once we found a good combination of oils and began buying them from our local oem, we found that our problems with stability went away.
    One thing you haven’t mentioned, what type of fragrance are you using?
  • Aijalon

    Member
    March 16, 2016 at 7:29 am

    We get our fragrance from Givaudan and Eurofragance via a distributor here in our country. It’s oil-based and natural. Our colorants are also oil-based.

  • David08848

    Member
    March 16, 2016 at 12:19 pm

    Coconut Oil should only be used in the 20-25% range because of the drying/irritation it can cause.   A larger percentage of Palm oil was a good suggestion and an even larger percentage of an oil such as olive with a high percentage of oleic acid would be a good choice as well.  You need to reformulate to deal with this rancidity problem and not produce as much if it is going to sit in a warehouse for months!

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