What makes angel food cake so light, airy and delicious? Angel food cake is different from most cakes because it uses egg whites, not traditional levening agents like baking powder or baking soda to rise. Egg whites don’t look like something that would help make a cake rise, but with the right treatment, they are!
Cakes rise because of gas bubbles. Baking soda and powder make carbon dioxide gas in a chemical reaction.Egg whites trap air when they are beaten.The air expands in the hot oven creating the light airy cake
Egg whites do not contain gas bubbles. Egg whites don’t rise up when they are fried. So what’s happening here? The egg whites don’t create the gas bubbles, they trap air as they are beaten. Science can help us understand how and why that happens.
Egg whites are made up of proteins and water. Parts of protein molecules are attracted to water (hydrophyllic) and other parts are not (hydrophobic). In the raw egg, the proteins are folded so that the hydrophobic parts are on the inside and the parts that are attracted to water are on the outside. When the egg whites are beaten, the folding is disturbed (denatured) and, at the same time, air is beaten into the mixture. This creates a foam which holds pockets of trapped air. Because the pockets are fragile, bakers must be careful when adding the flour to the mixture. Folding, rather than mixing is used to keep as many bubbles as posible!
When the foam is heated, the trapped air bubbles expand creating the light and airy cake that taste so good! Heat also makes the foam solidify, so the cake don’t collapse while it cools. To be extra careful, most tube pans have small “feet” so that the cake can be cooled upside down to keep the cake high while it cools.
Angel food cake is not too hard to make.Two parts need extra attention. First, be careful when separating the egg whites from the yolks. It’s important to keep fat of any kind away from the egg whites because fat will interfere with the formation of the foam. Egg yolks contain fat, so keeping the yolk away from the white is critical. Fortunately, many inexpensive devices to separate eggs are availble for people who are not comfortable separating eggs by hand (just grab the yolk but make sure to clean your hands well before and after) or by dipping the yolk from one half of the cracked shell to the other and letting the white fall into a bowl. Adding the flour to the egg-sugar mixture must also be done carefully. Instead of stirring with a spoon, the flour is sifted on top of the egg whites in smaller portions and folded into the batter with a rubber spatula. While both these steps need to be done carefully, don’t be intimidated! With a little practice, anyone can make a great angel food cake.
A typical angel food cake recipe uses a dozen egg whites and fills a ten inch tube pan. This size cake is great for larger parties The recipe included here only uses 4 egg whites and, instead of a tube pan, makes 12 cupcakes. This recipe is perfect when you only want to serve a few people. Angel food lasts a few days at room temperature or can be frozen.
Angel Food Cupcakes
Makes 12 cupcakes
10 tablespoons granulated sugar, divided
6 tablespoons all purpose flour
1/4-teaspoon salt
4 egg whites
1/2-teaspoon cream of tartar
1/2-teaspoon vanilla extract
1. Preheat the oven to 350oF
2. Line cupcake pan with 12 paper lines
3. In a small bowl, mix 4 tablespoons (1/4 cup) of the sugar, the flour and the salt. Set aside
4. Separate the eggs (save the yolks for another use)
5. Combine the egg whites and cream of tartar in a bowl.
6. Beat the mixture (use a whisk attachment, if available) until it forms soft peaks. (The whisk will start to leave lines through the egg whites.)
7. Gradually add the remaining 6 tablespoons of sugar (about a tablespoon at a time)
8. Beat the mixture until it forms stiff peaks (a fairly stable peak forms when the whisk is removed)
9. Mix in the vanilla extract.
10. Sift the dry ingredients over the egg white mixture, a third at a time. Gently fold the dry ingredients into the egg white mixture using a rubber spatula after each addition.
11. Bake for 18 - 22 minutes. The cupcakes are done when a they are light golden brown on top and a toothpick inserted into the center of a cupcake comes out clean
12. Cool the cupcakes in the pan.
