9.1 Introduction to Egg White Foams
Before You Come to Lab
Name: _________________________________
Watch the “Science: The Magic of Meringue — Why Timing Matters When Whipping Egg Whites and Sugar” posted on Canvas.
1. When is the ideal time to add sugar to egg whites when making a sweetened egg white foam (meringue)?
Watch the Chocolate Soufflé Recipe video posted on Canvas.
2. How is the egg white foam combined with the chocolate mixture?
Egg White Foams
Egg white proteins can foam when beaten, allowing them to be the structure in recipes such as angel food cakes, souffle, and meringues.
Egg whites foam because proteins denature upon beating and form a film around air bubbles.
The first step of making an egg white foam is to separate the white from the yolk using an egg separator (not the shells due to food safety concerns).
Then the egg whites are beaten to the stage listed in the recipe. There are 5 stages:
- Foamy: large air bubbles, very soft, used as an egg wash.
- Soft peak: peaks hold their shape but fold over easily, the point at which other ingredients are introduced.
- Upper soft peak: peaks hold shape and fold over slightly, endpoint for meringues and angel cakes.
- Stiff peak: peaks hold shape and do not fold over, used in macaroons and hard meringues.
- Dry: dry, resulting from overbeating, the protein in the foam has been denatured too much, resulting in a dry foam and water layer in the bottom of the bowl.
Important Ingredients and Steps to Consider
- Cream of tartar is an acid that helps stabilize the foam.
- Folding is a gentle mixing step that allows egg white foam to be incorporated into recipes without breaking down the foam
- Fat needs to be avoided when making egg white foams. Fat of any kind (from yolk or other sources) inhibits or limits foam formation. The fat interferes with protein foam on the air bubbles’ surface.
