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The Science of Baking Cookies

Many chefs can make a proper chicken breast, pasta, and many other dishes without a fuss. But when it comes to baking, it’s an entirely different story. That’s because more than being an art, baking is a science. Baking requires both keenness and precision. At its core, it is about mastering which mix of ingredients works and which one doesn’t. Ingredient amounts matter a lot because even the slightest addition or reduction of ingredients could mean the difference between the end product being a masterpiece or just average. The old saying “the devil is in the details” isn’t just true when dealing with collectors — particularly rings true when it comes to the science of baking cookies. Every detail counts, whether it’s the proportion of sugar, salt, flour, fat, or eggs, you shouldn’t leave anything to chance.

In this article, we will explore the science of baking cookies. More specifically, we will explore how to mix different ingredients to create both structure and flavor in your cookies.


Flour can make dough crispy, crumbly, or chewy depending on it’s ratio to the rest of the ingredients in the dough. Like in shortbread, a high ratio of flour in the dry cooking dough to the little amount of liquid in butter creates a tender and crumbly texture. Cookies such as pinwheel or biscotti need to maintain shape while baking and should also have a high flour ratio. When baking fluid-batter cookies such as brownies, it is ideal to use a lower flour ratio to the amount of liquid to create a chewy or cake-like texture. The flour ratio you should use when making drop cookies falls somewhere in the middle of the two examples above. The exact ratio of flour you should use depends on whether you want your drop cookies to be crisp or soft, crumbly or chewy, or thin or thick.

Although bleached and unbleached flours are interchangeable cookie recipes, it is worth noting that the bleaching process changes protein structures. This results in less formation of gluten in batter and doughs made using bleached flour. Therefore, it is better to use unbleached flour when you want to create a more chewy texture, as in nut bars and drop cookies.

Using whole-grain flour like whole wheat is another baking alternative. It would be a good idea to substitute no more than 30% of the flour with a whole grain flour if you desire to create a nutty and hearty flavor. However, if you desire to make a slightly gritty, less chewy, and dense cookies, a higher ratio of whole-grain flour would be ideal.


When it comes to baking cookies, granulated white sugar plays many roles. Not only does it add sweetness, but it also adds more brownness to the cookie and absorbs moisture in the dough, making it more crispy. Granulated white sugar also facilitates spreading as the sugar melts. The ratio of sugar used in most cookie dough recipes is very high, and only about 50% of the sugar used dissolves when mixing. More sugar dissolves in the baking phase causing the dough to soften and spread. If you would like an ideal outcome, use pure cane sugar since products with both cane and beet sugar are less consistent in quality.

On the other hand, Brown sugar makes cookies more chewy and moist. Dark brown sugar contains about 20% molasses, while light brown sugar contains about 10% molasses. Molasses add moisture, and since it is a bit acidic, it makes the proteins in the cooking dough to become firm more quickly, thus creating a more chewy texture.