Heat and Hold raw ingredients in emulsions

ZaraZara Member
edited November 2020 in General
Is it true that you have to heat and hold the water and oil/emulsifiers at a particular temperature (70 degree) before mixing them? 
I use distilled water and boil it and let it boil for 5 minutes and just melt the oil part. 
I really appreciate your input. 

Comments

  • Nope!

    Many old threads on this issue...search them.

    Many modern formulas are now cold process....go figure!

  • Boiling water wouldn’t hurt. You can wait until it cools down and use it in cold process formula. I use steam distilled water which I buy in 5lt containers. It’s not sterile to begin with (although food grade) but the moment that container is opened it’s not as clean as it was. And since it takes me around a month to use that container I boil it each time after the first use. I noticed that erlenmeyer flasks work pretty well for this purpose. Water heats faster than in a beaker and it partially traps the vapor.
  • Many o/w formulas contain waxes and waxy emulsifier which often melt at 65-80 C. Maybe that’s where 70C came from?
  • Thank you for your responss,
    I understand that you need to boil the distilled water to sterlie it but I don't understand that you need to keep it in that temperature for 20 minute. I don't believe there is no point. 
  • Nope. I never ever ever heat and hold.
  • ZaraZara Member
    edited November 2020
    Thank you everyone,
    I never use heat and hold method but the problem is, there are lots of misinformation on the internet and just wanted to make sure.
    Thanks again , I really appreciate for sharing your knowledge. 
  • PerryPerry Administrator, Professional Chemist
    It depends on your formula because as @ngarayeva001 said, a number of formulas use fatty alcohols and waxes that melt at around 60 - 70C. When creating an emulsion with them you need to melt them so the temperature has to get over 70C just to use them. But "heat and hold" is often suggested as a preservative strategy. This is not a good preservative strategy.

  • MicroformulationMicroformulation Member, Professional Chemist
    We used "heat and hold" with older emulsifiers (non-ionic emulsifiers) to essentially get a more stable emulsion. The temperatures and pressures were NOT high enough to sterilize the water. The newer emulsifiers do not require this step in my experience.
    markfuller@microformulation.com Microformulation.com Microformulation Cosmetic Consulting provides Custom Formulations for both large Commercial accounts as well as smaller entrepreneurs. We can provide Naturally compliant Formulations under the NSF, NPA, Whole Foods and USDA Organic Certifications. BS.Pharm Albany College of Pharmacy, Union University.
  • Perry , Thank you , I've read this method first time on Swiftycraftmonkey blog. I don't believe keeping the oil/wax and water portion at 70 degree for 20 minutes would do any good but it was like a what if. :)
    Microformulation , thank you.
  • PerryPerry Administrator, Professional Chemist
    @Zara - Generally, when making an emulsion that uses ingredients like Cetyl Alcohol, Stearyl Alcohol, Glyceryl Stearate or other fatty acids/alcohols/waxes, it makes sense to heat above 70C and hold it there for some time. This is to melt the materials and ensure they blend together.

    Also, when you create the emulsion you heat up the water to the same temperature and mix the two phases together. The heat (and mixing) will ensure you get smaller emulsion particles. This will lead to a more stable emulsion. 
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