What does sugar add to an egg white foam?

Reader Allison writes:

Could you explain how sugar effects [the egg white foam] equation? I know that meringue I make with a higher sugar content holds longer for me (in addition to Italian meringue that holds even longer.) It seems to stabilize it, but I would love to know more about the science.

That’s a really interesting question. As soon as sugar hits the watery egg white, assuming you’re not adding too much or too much at one time, the crystals begin to dissolve. As they do so they combine with the water to make a syrup. The more sugar, the denser the syrup, and it surrounds the protein-reinforced bubbles, creating a sort of cushion in the spaces between the bubbles. Think of the sugar molecules like packing peanuts among a bunch of glass Christmas ornaments in a shipping crate. That’s pretty much what they are.

4 thoughts on “What does sugar add to an egg white foam?”

  1. Hi,

    Thanks for all your postings. I’ve been following your blog for a while now and tried quite a few things from it too and drooled over the rest 🙂 The carrot cake was especially great !

    My mom is always concerned about how much sugar she takes (she’s at risk for diabetes) Is there anyway I can reduce sugar from a cake recipe.. and by how much please? I’d like to make her something that she can eat without worrying so much about the sugar content.


  2. Hello there joepastry, I’m interested in this also. (See my latest blog post.) Your blog post was really good to read, you’ve certainly given me lots of food for thought!


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