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.