In the last couple posts, we’ve seen that the temperature of cookie dough affects its spread and texture, which explains why many recipes chill the dough for a couple hours. But what about chill times that range from one to three days? That’s more than enough time for the dough to cool. These long periods of refrigeration, which are also called “aging” or “ripening,” are meant to improve the flavor and texture of our cookies. In this experiment, we’ll explore how significant these changes really are.
Experiment Overview
Goal: To see and taste differences in cookies as the dough ages
Recipe: Ultimate Chewy Chocolate Chip Cookies by Handle the Heat
Method: Prepare the cookie dough. Bake a couple cookies, then refrigerate the rest of the dough. Bake the remaining cookies 3 days later.
Results: As the cookie dough aged, we noticed
– Drier dough
– Thicker cookies with less spread
– More browning
– Chewier texture
– Improved flavor
Conclusions: Aging cookie dough affects its spread, texture, and taste. The improvement to flavor alone is reason enough to wait!
Testing Method
Ingredients and Equipment
- Ingredients as listed in Ultimate Chewy Chocolate Chip Cookies
- Stand mixer
Baking the cookies
- Prepare the cookie dough as described in the recipe. Form two balls of dough, each 57g. Refrigerate the balls for 1.5 hours. Cover the remaining cookie dough with plastic wrap and refrigerate 60 hours.
- Toward the end of the 1.5 hours, preheat oven to 350°F. Bake the 2 cookies for 14 minutes. Cool for 5 minutes, then remove to wire rack to cool completely. Wrap tightly in plastic and freeze. These are the Day 0 cookies.
- After 60 hours, remove the remaining cookie dough from refrigerator until soft enough to scoop. Form 4 balls of cookie dough, each 57g, and refrigerate overnight.
- The next morning, preheat oven to 350°F. Bake 2 cookies for 14 minutes and 2 for 16 minutes. Cool for 5 minutes, then remove to wire rack to cool completely. These are Day 3 cookies. Remove the Day 0 cookies from the freezer and thaw at room temperature. Taste and compare.
Results
To better understand some of these results, I suggest reviewing the post on starches and their relationship to sugars. Remember that starches are long chains of sugars. Both starches and sugars absorb water.
Also, as you’ll see, I under-baked the Day 0 cookies in this experiment. I baked two Day 3 cookies for the same amount of time in order to control for any variability from bake time, but I will also describe the science behind other people’s observations that we didn’t see in my under-baked cookies.
Drier dough
After three days, the cookie dough felt drier. In the past, I’d always assumed that I hadn’t wrapped the dough tightly enough in the fridge and all the moisture evaporated. But the water actually stays in the dough. It just migrates.
Most cookie dough is fairly dry. In this recipe, the only water comes from the eggs and butter. Even so, freshly mixed cookie dough is wetter than aged cookie dough. The water in the eggs is thickened by proteins, so the other ingredients can’t absorb it quickly. And the butter coats the flour and keeps it dry.
However, as we’ve discussed, the chemical structures of starch and sugar make them extremely attractive to water. So if we give the dough time, the water slowly migrates from the eggs to the flour and sugar. In flour, starch holds most of the water, but proteins such as gluten and enzymes also hydrate. When we unwrap the dough three days later, the dough feels drier and firmer because most of the water has been absorbed.
Note that water absorption is a chemical process whose rate, like all chemical processes, changes with temperature. At warmer temperatures (like room temperature), molecules have more energy to move faster, so the water would migrate to the flour more quickly. However, to prevent bacterial growth, we want to refrigerate the dough. Remember, too, that we also want to chill the dough to control spread.
If the temperature is too cold, water absorption slows. In the freezer, for example, water molecules solidify into ice and stop moving. So although the freezer is a good place to store cookie dough long-term, the dough won’t really age there. If you’d like to store aged cookie dough, you can move it to the freezer after a couple days in the fridge. Even better, you can age the dough, portion it into individual cookies, then freeze. When you want a warm cookie, you can bake one straight from the freezer.
Thicker cookies with less spread
Since the Day 3 dough was drier, it spread less than the Day 0 dough. The Day 3 cookies also baked up thicker because they spread less. As we’ve discussed in the last few posts, cookie thickness changes the texture of the cookie. Thinner cookies bake up crisper the whole way through, while thicker cookies have a greater contrast between crunchy edges and soft, gooey centers.
I got an even more dramatic difference in spread when I tried this experiment with Sally’s Baking Addiction’s oatmeal raisin cookies. Like flour, oats can absorb a lot of water, and just one day in the fridge significantly reduced the spread of these cookies. This also improved the cookies’ overall appearance since the oats were more evenly distributed.
More browning
As you can see from the side view of these cookies, the Day 3 cookies developed more color than the Day 0 cookies. I also expected the browning to be more even in the aged cookies, but unfortunately, we could not observe this difference because I under-baked the cookies and they didn’t brown much.
As cookie dough ages and dries, the concentration of sugar increases, and sugar enhances browning. Not only does sugar concentration increase as water is absorbed, but more sugars are actually added to the dough. This is the work of an enzyme in flour called amylase.
You may remember amylase from our discussions about yeast and bread, or perhaps from eggs and custards. Once hydrated, amylase breaks down the large starch molecules in flour into sugar molecules. With time, amylase creates more and more sugars from the starch. These sugars are chemically identical to the sugars we add to the dough, so they also contribute to browning.
Chewier texture
The increase in sugar concentration is also responsible for changes in the texture of the cookie. I did not notice a difference in this experiment (again, perhaps because I under-baked the cookies), but other sources say that aged dough bakes crisper or chewier cookies, while Day 0 cookies tend to be softer and cakier.
As we’ve discussed, sugar plays a huge role in the texture of cookies. As a cookie bakes, the sugar dissolves or melts, but when it recrystallizes, it’s responsible for crisp, crunchy textures. Brown sugar also contains a specific type of sugar called fructose that makes cookies chewy because it holds onto more water than the sucrose in granulated sugar. (Molasses and honey also contain a lot of fructose.) As cookie dough ages, the concentrations of these sugars increase due to water absorption and amylase activity. So the texture of the baked cookie also changes.
Improved flavor
Although I didn’t notice any variation in texture, I was immediately blown away by the difference in taste between the Day 0 and Day 3 cookies. The Day 0 cookies just tasted sweet. But the Day 3 cookies had a deeper, more complex flavor. I’m not sure how to describe it, but other people have characterized it as caramel, butterscotch, or toffee notes. Whatever the flavors were, they were undoubtedly better than the Day 0 flavor.
I will note that I tasted these cookies side by side. I’m not confident that I would have noticed anything without a comparison. And the other two taste testers did not report any differences in taste despite trying both cookies together. So although aging cookie dough improves its flavor, the change may not be discernible to all palates. With the oatmeal raisin cookies I mentioned earlier, the effects of aging on flavor were not so pronounced, and I wasn’t sure if I actually tasted a difference in the aged dough. These cookies were more heavily spiced, which probably masked the effects of aging on flavor.
Aging improves flavor for some of the reasons we’ve already described. As water is absorbed by flour, flavor compounds become more concentrated. And because sugar enhances flavor, additional sugars from amylase activity also affect the taste of the cookie. But aging also gives distinct flavors—from vanilla extract, butter, brown sugar, and all the other ingredients—time to meld together into a more unified taste. Think about how the spices in chili or tomato sauce blend into something more than the sum of their parts as they simmer. Aging cookie dough similarly gives flavors time to marry and intensify.
Conclusions
The process of aging undoubtedly changes cookie dough at the molecular level. Water absorption and enzyme activity dry the dough and increase sugar concentration, but the magnitude of change in spread, color, texture, and browning depends on the specific dough. And although flavors also intensify and meld together, the benefits to taste may be more noticeable to some people than others.
From this experiment, I’ve learned that, if a recipe calls for it, aging my cookie dough will improve its flavor, and that alone is enough reason to wait. However, if I don’t have the time to age my dough, I am confident the cookies will still be presentable if I skip the aging step. (In that situation, though, I would look for a recipe that does not require aging!)
References
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Corriher, S. O. Bakewise; Scribner: New York, 2008.
Corriher. S. Give It a Rest: Why Some Dishes Taste Better with Time. Fine Cooking.
Figoni, P. How Baking Works, 3rd ed.; John Wiley & Sons, Inc.: Hoboken, 2011.
Gaines, C. S.; Donelson, J. R.; Finney, P. L. Effects of Damaged Starch, Chlorine Gas, Flour Particle Size, and Dough Holding Time and Temperature on Cookie Dough Handling Properties and Cookie Size. Cereal Chemistry 65(5), 384–389, 1988.
Hamel, P. Chilling cookie dough. King Arthur Baking, 2015.
Leite, D. Perfection? Hint: It’s Warm and Has a Secret. The New York Times, 2008.