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.

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Fat: The Foam Foiler

There is a popular myth which holds that even a speck of egg yolk, butter or oil can make an egg white foam all but impossible to form. This is, um…a myth. Sure, you ought to go out of your way to prevent fat or other oily and/or soapy substances from coming in contact with […]

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The Clenching Fist

The frustrating thing about fiddling with egg white proteins is that the same whipping action that uncoils them will cause them to bunch and clump if you don’t quit while you’re ahead. The point of no return occurs somewhere right after the stiff peak stage, when the proteins that were arranged in nice regular lattices, bonded elegantly, cradling big fat bubbles of air…start to lose their mojo.

What happens? In a nutshell, the excess agitation causes the protein molecules to bond excessively to their neighbors and gather together in masses (coagulate). As this happens water molecules are squeezed out from between them and the forces of surface tension start to take over again. The bubbles start to pop. The foam starts to turn grainy, then clumpy, then watery, at which point it’s pretty much useless.

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Let’s Talk Foam

What’s a foam but a bunch of bubbles? Masses of air surrounded by thin walls of liquid. The shape of a bubble is a factor of surface tension, i.e. the pull that the water molecules that make up the wall exert upon one another. That pull causes the wall to reduce itself into the most […]

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Making Crème Anglaise

The process of making crème anglaise is almost identical to that of other stirred custards like pastry cream. It simply involves heating your milk and/or cream mixture, then slowly adding it to the yolks so as to avoid cooking them. After that you simply bring the mixture up to temperature and presto — you’re done. Start by scraping the vanilla seeds into the milk. You can substitute a teaspoon of vanilla extract, but custards make real vanilla shine. Use it if you can.

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Crème Anglaise Recipe

Crème anglaise is a standard that every aspiring pastry maker needs to know how to prepare. Essentially it’s just a custard (of the “stirred” variety), that’s so thin that it can be used as a sauce. It’s most common application, however, is as an ice cream base. To make it all you need is:

seeds from half a vanilla bean
2 cups whole milk (for a richer result use half milk and half cream)
4 egg yolks
1/3 cup sugar

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This Week: Floating Islands

Îles flottantes is a dessert that everybody’s familiar with. In France. Here in the States, and I dare say in lots of other places on Earth, it’s virtually unknown. Why I can’t say, but it’s a treat you’ll find in France wherever simple food is served: in bistros and in homes. It’s comfort food, in other words. But what exactly is a “floating island?” Basically it’s a blob of meringue poached in milk, floating in a puddle of crème anglaise and topped with caramel and/or nuts. It’s sweet but not too sweet, rich but not too rich, light but satisfying. In many ways a perfect dessert. If you’ve never tried it, you’re in for a very pleasant surprise.

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Making Cheese Wafers

My grandmother was born and raised in Chicago, but these wafers seem to me to be Southern in origin. Not only are they topped with pecans, but their flavor profile bears an uncanny resemblance to a classic Southern spread: pimento cheese. Regardless of where they come from you’ll find them rich, tasty and refined. Begin by preheating your oven to 325. Combine the flour, salt and cayenne pepper in a bowl or the bowl of a mixer fitted with the beater and stir on low.

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The Making of a Cook

My mother’s mother was a wondrous cook. Or perhaps I should say she became a wondrous cook. When she and my grandfather were first married in 1928 my grandmother knew next to nothing about the subject of cookery. An attractive, bookish type, she was far more interested in the law than in roasts or pies (she had the distinction of being the first female graduate of Loyola University’s law school). Those interests were to change once my grandfather realized that her kitchen repertoire consisted of little more than light salads, vegetables and other insubstantial, womanly fare. So he sent her to cooking school.

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