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How to make fluffy, delectable meringue using science

A scientific look at the power of eggs.

by Madeline Muzzi
Updated: 
Originally Published: 

Chemically speaking, egg whites and egg yolks are quite different. Egg whites are about 90 percent water along with some protein. Egg yolks, on the other hand, have plenty of fat mixed in with their proteins.

This difference in their composition results in distinctly different properties and taste. When separated, eggs can make things as light and fluffy as a meringue or as rich and decadent as pastry cream.

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Meringues are made from egg whites, sugar, and air. They're essentially bubbles trapped in a scaffolding of egg white proteins.

Some of the proteins in an egg white attract water and some repel them. When the whites are vigorously whipped, air is forced in and the entanglement of proteins separates. The water-loving proteins cling onto the water, while the water-repelling proteins cling onto the air, creating bubbles.

80%

After it's completely dry, the meringue will be almost weightless. This is because meringues are around 80% air.

Unlike light and fluffy egg whites, egg yolks excel at making things decadent and creamy.

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In addition to rich flavor, egg yolks have the power to thicken liquids. When egg yolks are heated, the protein strands unfold. As the strands reach out to connect to other proteins, they trap moisture and tie the whole mixture together.

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That's what makes lemon curd, crème brûlée, and pastry creams thick.

You can see this transformation take place. As the mixture is heated, it will thicken and coat the back of a spoon.

Taking advantage of the unique properties of eggs can create a fluffy and creamy pavlova.

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