Mixing speed for lotions & creams, excessive air in a finished lotion, size of mixing bowl.

Sorry for asking 3 questions at once. I haven't seen posts that cover these 3 topics. 

I am now using a stand mixer, Sunbeam brand, for domestic use,  NOT a professional piece of equipment. 

When mixing the ingredients for a lotion or cream is it best to start mixing fast, then slower, or slower first, then fast? 

Sometimes my lotions are a little more airy than I like, probably due to excessive mixing speed. Any ideas how to get the excess air out? Sometimes gently whamming the jar bottom  on a padded table helps, but not always. 

I do not have professional equipment, so I cannot apply a vacuum to the batch to suck out excess air. The fluffiness of the lotion makes it hard to get it out of a pump bottle. I do not want to use plastic squeeze bottles because there is already too much plastic floating around. Plus the canning jars I use are re-usable & are easily sterilized with home-brew sterilant solutions. 
  
My formulae and heat & hold periods are not the problem causing the separation because the formulae worked well when I used a stick blender.  I was unhappy with the stick blender because the motor heated up too much AND because it caused fluffiness in my lotions. 

Can using a rather large bowl for a small amount of lotion cause inadequate mechanical emulsification because the water & oil phases aren't being brought together well enough in a large bowl?  I have found that a 200 gram batch may work out really well, but then when I try to make a 600 gram batch in a large bowl, it separates. I am guessing the bowl was too large? 


Comments

  • BobzchemistBobzchemist Member, PCF student
    This does not sound like a problem we can help with, other than to suggest different equipment to process your batches with.
    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."
  • I made 2 batches yesterday, in different mixing vessels. I made the exact same formula so if I had a failure, the mixing would be to blame.

    The 200 gram batch was mixed in an IKEA metal measuring cup. I started off mixing at almost maximum speed, then to a more medium speed. Total mix time was 15 minutes with breaks scattered throughout to allow the motor to cool off. I use a split plastic bag over the mixer to keep the splattering from going all over the kitchen AND to try to keep air currents from depositing things I can't see,  into the lotion.  NO separation so far :)

    The 600 gram batch was mixed in the smaller bowl that came with the stand mixer. That was also mixed at very high speed to begin, then to a medium speed. Total mix time was 21 minutes because I feared any less would mean the mechanical emulsion would not have happened. This is also staying emulsified, so far. 

    My most recent lotion failures showed separation within a mere 2 hours, so I think this is a success. 

    So I guess it is very important to use the right-sized mixing vessel for different batch sizes.


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