How to Bake the Best Cake, According to Science
There is an oft repeated saying that cooking is an art and baking is a science. That’s because when you’re cooking, most foods are pretty forgiving – you can “guess” the amount and let your taste and preferences guide you along the way. But when you bake, you fly blind. You can’t tell much from the taste of the dough, and you can’t spoon out the taste as it bakes.
You can usually fiddle with the parts of the cake that give it flavor, but with the more “functional” ingredients in baking – butters, eggs, baking powder – precise proportions are important. NPR’s science podcast Short Wave recently showcased the science of cake baking: To celebrate Short Wave ‘s third birthday , the show enlisted the help of biochemist-turned-baker Adriana Patterson and used science to help make a more fluffy and delicious cake. And you can too.
“We like to say that everything is science, and science is for everyone,” Short Wave producer Kimberly McCoy told Lifehacker. “The short wave is an inclusive experiment. We want to involve as many people as possible in science.”
How science can help you bake a fluffy pie
According to Patterson, the cake is “a stabilized baked foam” similar in texture to a biscuit. If your goal is to make a very fluffy baked foam, you need to add as much air as possible. “The more air you blow into it, the more spongy and fluffy it is,” Patterson explained in a podcast.
Adding a leavening agent, such as baking soda, to cake batter increases its carbon dioxide content substantially. When mixed with an acidic ingredient and a liquid, baking soda creates small bubbles in the batter or dough—bubbles that you should protect by not stirring too much. As soon as you add heat, the air bubbles expand, resulting in a fluffy cake.
But if you want a very fluffy cake, you need more than just baking soda and powder. You need science – and meringue. Egg white is about 10% protein in the form of long chains of folded amino acids floating in water. “When you whip it at high speed, you are essentially turning on the air and spinning the egg whites,” Patterson said. “Once these proteins are untangled, they create a web that contains an air clot,” Patterson said. The addition of an extra web of air pockets means even more fluffiness.
Cream glaze is a colloidal dispersion of C12H22O11 and milk phosphoprotein.
The chemistry of cake icing is simpler than cake icing, as there are no reactions from the heat, but buttercream is still quite scientifically interesting.
“Buttercream is an emulsion,” Patterson explained. “It has a special component or molecule called an emulsifier that holds water and oil together. In butter, it is the casein that holds the fat and water together.”
The slightly crunchy texture of some types of buttercream frosting is the result of an excess of solid sugar compared to the liquid part of the frosting. Only a certain amount of solid sugar can dissolve in water and fat, so undissolved grains of sugar remain suspended in the glaze. But it’s easy to make a smooth buttercream with non-solid sugar. “The butter has enough casein so that we can add more water-based ingredients and still have that stability. We can add honey. We can add maple syrup. I like corn syrup because it has a neutral flavor that can be seasoned to your liking.”