The Science of Baking: How Physics and Chemistry Can Make You a Better BakerMarch 26, 2014
Baking is a science. Almost all baking recipes call for flour, eggs, fat, sugar, and a leavening agent (baking soda or powder), and follow a standard sequence of steps. If you follow all the instructions precisely, your end product is always the same. That’s what science is about, accuracy in its methods and results that can be reproduced consistently. Mostly, baking is physics and chemistry, both of which we are breaking down for you via our step-by-step illustrated guide.
Step 1: Creaming sugar and butter
The process of creaming is, simply put, just mixing butter and sugar together. But under the dizzying whirr of your paddle mixer, a third component is being incorporated, air. The jagged sugar crystals cut air into the butter and the butter forms a layer around the air pockets, making the mixture lighter and fluffier.
Step 2: Adding the egg
Eggs serves three purposes in baked goods. First, the protein in the eggs forms a layer around the already butter-covered air bubble, preventing it from collapsing while baking in the oven. Second, it provides much-needed water to the batter (more on that later). Lastly, it gives your baked goods that appetizing tinge of yellow.
Step 3: Folding in the flour
Flour gives your baked goods structure, via gluten—a mixture of two proteins present in cereal grains. They form an elastic network around the air bubbles you worked so hard for, helping your baked good hold its shape, even through the structural stress of expansion that happens while baking. Take care, though, not to over-beat the flour. This will result in a heavy and dense cake, that can be unpleasant to eat, because of too much gluten development.
Step 4: Heating things up
The rise in your baked goods comes from two things. First, when your leavening agent is heated, whether it’s baking soda or baking powder, it releases carbon dioxide into the dough or batter around it. As the temperature rises even higher, vapor forms from the water in the butter and eggs. All this gas expands, enlarging the existing air bubbles in your batter. To prevent the gas from escaping, the gluten that you developed through the previous step holds everything together, keeping the baked good whole. For easy visualization, think of your cake as a network of tiny, soon-to-be-delicious balloons.
Step 5: Settling down
As the heat continues to rise, the egg proteins coagulate, the starch in the flour absorbs any remaining moisture, and the gluten loses its elasticity. The batter has now set, taking its permanent shape.
Step 6: Browning
Ever wonder why your raw batter doesn’t taste exactly the same as the end product? That’s because during baking, the Maillard reaction works its magic, breaking down the sugars and amino acids in your batter to form flavor compounds that mere mixing and folding doesn’t. Apart from the flavor it imparts, this chemical reaction is also responsible for the golden brown color of pastries and breads (and even steaks and dulce de leche).
Finally, after all the physical and chemical reactions, the breaking down as well as the development of bonds and flavors, and yes, all your hard work too, your cake is now ready to enjoy.