Emulsion - water retention

Hi all, 

I am trying to make an o/w emulsion. New to emulsions here, but had a question. If I have a formula that uses say 50% water (lets also say its its 50g by weight). As i heat the oil phase and the water phase up to the right temperature (70-80C), wouldnt the water phase drop below 50g on heat up/evaporates and therefore throw the formula off?

Also depending on what vessel I use and the volume of water i to heat up, wouldnt the evaporation rate differ? 

If so, what is the best way to retain water? Do most chemist just bench the use of more water to account for evaporation/water loss during heat up stage?

Thank you so much!


  • Yes, rather than try to retain the water you can heat more than enough to compensate for evaporation. Measure right before mixing.
  • MicroformulationMicroformulation Member, Professional Chemist
    In the lab, it is easy to compensate for water loss by using the predicted weight of the vessel/product and accounting for the water loss. On the floor, it requires that the water loss be extrapolated in process scale-up. (An educated guess).

    Now, to be more precise, in manufacturing this factor is rarely monitored unless it is a Formulation that is fairly brittle in this regard. At 80C and with covered tanks, it is less significant than you may believe.
    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.
  • I figured out in an empiric way that usually 2-3% of water is being lost during heating, which depends on the shape of your beaker.  So I just add more water initially.
  • Large industrial-scale tanks have some welded, protuding marks to top it off with some extra water compensate for evaporation.

    You can do the same, just don't blindly trust the beaker marks as they're often way off
    Check the marks with a quality graduated cylinder

  • Thank you all for your responses! Really appreciate the help here as I am new to the process. Thank you!
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