Egg White Magic

Big question: How does a runny, clear egg white turn into a fluffy white cloud?

Whisk egg whites from liquid to foam to soft peaks, add sugar, and see how trapped air and sugar build a glossy cloud.

What you need

• 2 eggs
• 2 tablespoons sugar
• A large, very clean, dry bowl
• 2 small bowls for separating the eggs
• A whisk, or a grown-up with an electric mixer
• A small plate
• A timer

What to do

1. Separate the eggsWash your hands first and check every ingredient with your grown-up. Separate the eggs the way you learned in Lesson 6, or ask your grown-up to do it. Put only the clear whites in the large bowl, with no yolk at all. Wash your hands after touching raw egg.
2. Make foamWhisk hard. The clear liquid turns cloudy and bubbly, like bath foam. Take turns, or your grown-up can switch to the electric mixer, which is a grown-up job. Keep fingers and spoons away from the beaters, and your grown-up turns the mixer off and unplugs it before anyone lifts the beaters or adds sugar.
3. Soft peaksLift the whisk. If the whites make a little mountain that flops over at the tip, you have soft peaks. Put one spoonful on the plate.
4. Add sugarWhisk in the sugar a spoonful at a time. The foam turns thick, shiny and bright white.
5. ComparePut a spoonful of sugared foam beside the plain one. After 10 minutes, which one sags?

What is happening?

Egg whites are mostly water with proteins in it. Whisking beats in tiny air bubbles, and the proteins unfold and link up around each one, making thin walls that hold the air in. Even a tiny bit of yolk or grease gets in the way of the proteins, so the bowl must be very clean and dry. Sugar dissolves in the water in those walls and makes it thick and syrupy, so the walls drain more slowly, the bubbles last longer and the foam turns glossy. Beaten eggs trap air in cake batter too.

Raw egg can carry germs, so no tasting the raw egg foam and no licking the whisk or spoons. When you finish, wash your hands with soap and water. Your grown-up throws the foam away and washes the tools in hot, soapy water.

Try it

• 
  Junior Bakers

  Vanilla Cupcakes

• 
  Junior Bakers

  Funfetti Cupcakes

Check yourself