Jess Bailey / Unsplash
Glass jar of flour with a wooden spoon

Cooking is chemistry! Bake a mug cake and explore the science of leavening

biologyZoe Harvey, Marketing Communication SpecialistJun 5, 2020

Cooking is something we do everyday that doesn’t feel like science, but it is! By deciding which ingredients to mix together, how to cook them, and for how long, we’re applying principles from chemistry, physics, and biology to create something delicious (hopefully!).

We’re showing you how to bake a simple mug cake, one of our favorite recipes from our Chemistry in the Kitchen summer camp, created by our educators and tested by campers.

The approximate time to create this mug cake is 15-30 minutes, depending on how many young cooks you have in the kitchen. We’re providing prompts to discuss how and why the cake rises so you can think about chemistry while making this sweet treat.

What you will need:

  • Microwave

  • One large coffee mug with a smooth interior (avoid handmade pottery and non-microwave safe mugs)

  • Fork or other mixing utensil

  • ¼ cup all purpose flour (or almond flour for gluten free)

  • ¼ cup white sugar

  • ¼ teaspoon baking soda

  • ½ tablespoon unsweetened cocoa powder

  • ⅛ teaspoon salt

  • ½ tablespoon vegetable oil

  • ¾ teaspoon of vinegar

  • ¼ teaspoon vanilla extract

  • ¼ cup water

  • (optional) chocolate chips

Step 1. Mix your ingredients

Mix the flour, sugar, baking soda, unsweetened cocoa powder, and salt in your mug. Then, slowly stir in the vegetable oil, vinegar, vanilla extract, water, and optional chocolate chips until there are no lumps.

In baking, leavening is the air that causes breads, cakes, and other baked goods to rise when cooked. That gas is produced in different ways, depending on what type of leavening agent you use. This, in turn, varies according to what you're baking, but the simplest way to think of it is that the leavening agent produces the gas, and the gas causes the dough or batter to rise. There are three main types of leavening agents:

  1. Biological - like yeast. Yeast is a fungus that uses sugar to produce CO2 gas and alcohol.

  2. Chemical - like baking soda and baking powder. Both are basic and react with acids to produce the gases for their products.

    • Baking soda reacts quickly, then is done producing gas. It often reacts with ingredients like buttermilk, lemon juice, yogurt, sour cream, or other acids.

    • Baking powder is considered to be a double-acting agent, which means it often reacts two times, right when it is mixed and again when it is heated.

  3. Vaporous - This is when the water in the dough reaches 212 F then vaporizes, which produces bubbles. Vaporous leavening is often used with butter. When butter is incorporated throughout the dough, the water within it gives off steam when heated.

What do you think the leavening agents are in this mug cake? Are they biological, chemical, or vaporous?

Step 2. Cook!

Microwave your mixture on 50% power for three minutes. Once it’s done, let it sit in the microwave for 1 minute to cool. Remove carefully, and enjoy (and make sure your cat doesn’t take a bite like mine wanted to!).

Did your cake turn out light and fluffy? If not, why do you think that is? An optional question for older kids and adults: how do microwaves cook food? Spoiler: microwaves cause water molecules in food to vibrate, which heats them up and helps us make delicious mug cakes, reheat leftovers, and more.

We hope you loved making your mug cake and eating it, too. Discussing how baking works is just as important as baking itself. With this cake, you used chemical reactions to create bubbles, making a light, fluffy mug cake in your microwave. In summary: you did science!

Share your mug cake masterpieces with us on social media using #ShareYourDiscovery or by tagging us in your posts. We’re getting hungry already.

Need another easy science recipe? Check out our three-ingredient beer bread or visit our science recipes Pinterest board.