You can’t think of the holidays without thinking of cookies! From gingerbread houses to sweet sugar cookies, everyone has a favorite—including a certain someone who is responsible for magically bringing presents to kiddos across the world!
It just so happens that National Cookie Day was last week, and because science and baking go hand-in-hand, we are going to explore the chemistry behind the perfect cookie! Too much flour, different fats, baking soda, and liquids, they all play a roll in crafting your cookie favorites.
First, let’s consider what holds our raisins, chocolate chips, and macadamia nuts together: the dough. Depending on the cookie, the dough can be created using different ingredients. For this example, we’ll use the classic chocolate chip cookie which requires eggs, butter, brown sugar, white sugar, baking soda, flour, salt, and vanilla. How do these things mixed together go from gooey to great? The answer: Heat causing a series of chemical reactions.
- You’ve just placed your dough on the cookie sheet and popped it in the oven. The heat causes the butter inside the dough to melt, which is what causes the cookie to go from a doughy ball to a round flat cookie.
- Next, your cookies will blow off some steam—literally! At 212 degrees Fahrenheit, the water in your dough turns into steam and the water vapor rises through the dough. Additionally, the baking soda starts to turn into carbon dioxide gas which will raise the cookie up even further.
- By now, you’ll start to notice that your cookie is turning golden brown in color, which means your cookie is just about done! Some tasty reactions are happening, including caramelization, when sugar reaches a high enough temperature, it begins to break down from clear crystals and transforms into a brown liquid, and the Maillard reaction. This reaction combined with reaction from the combination from the sugar and protein from the eggs and flour creates a simply scrumptious result.
You can conduct your own experiment by making a batch yourself and trying different ingredients, but if you want to make the classic chocolate chip cookie—look no further than this Ultimate Chocolate Chip Cookie Recipe.