Chilling cookie dough: Does it make a difference?

Why refrigerate chocolate chip cookie dough — or for that matter, any basic drop cookie dough — before baking? Does chilling cookie dough really make any difference?

The short answer: yes, chilling cookie dough prior to baking does make a difference. But the story behind that "yes" might surprise you.

We recently tested this question with a batch of chocolate chip cookie dough. Understand, though, that these results can be applied to other kinds of plain drop cookie dough: sugar cookies, snickerdoodles, etc.

First, we baked some of the cookie dough immediately, without any chilling. Then, we put the dough in the fridge and continued to bake cookies over the next 10 days, at regularly spaced intervals after aging.

The result?

Chilling cookie dough for just 30 minutes makes a big difference.

The cookies pictured above are the same size, weight-wise. But look at the difference in spread — the cookie dough that was refrigerated spread less. The cookie dough without refrigeration also browned less.

So, the longer the dough is chilled, the more the cookies change?

The longer you chill cookie dough, the smaller the changes become.

Call it the law of diminishing returns. The major difference is between no chilling at all vs. chilling cookie dough for 30 minutes. After that, the baked cookie continues to evolve — though very gradually.

Over time, chilling cookie dough produces cookies with darker color and more pronounced flavor.

Here you see the beginning and end of the test: Clearly the cookie baked from dough aged for 10 days in the refrigerator spread less and is darker in color. Its flavor is also more pronounced; our taste testers couldn't identify any particular flavor note that stood out above the rest, but simply noted that the cookie aged for 10 days "tastes better" than the cookie baked on day #1.

Overall, cookies baked immediately tasted rather flat; and their texture was soft and rather doughy, without being chewy. Cookies baked after chilling the dough (for as little as 30 minutes) became chewy, and progressively more flavorful with longer aging. 

So, what does chilling cookie dough do, exactly?

1) Chilling cookie dough controls spread.

Chilling cookie dough before baking solidifies the fat in the cookies. As the cookies bake, the fat in the chilled cookie dough takes longer to melt than room-temperature fat. And the longer the fat remains solid, the less cookies spread.

In addition, the sugar in the dough gradually absorbs liquid. If you bake the dough immediately, before sugar has a chance to absorb much liquid, that liquid remains "free" in the dough, and promotes spread. Think of this in terms of thin vs. thick pancake batter: the more liquid in batter, the more it spreads, right? Same with cookies.

2) Chilling cookie dough concentrates flavor.

As the dough chills, it gradually dries out, concentrating the flavors of all the ingredients. Think of watered-down lemonade, vs. lemonade with less water: dull flavor vs. bright, tangy flavor. Same with cookies.

Something else happens as the dough rests: part of the flour breaks down into its component parts, including a simple carbohydrate, sugar. Thus, since sugar is a flavor enhancer (like salt), the cookies may taste more flavorful, as well as sweeter after aging.

3) Chilling cookie dough changes texture.

Again, it's not really the chilling, but the dough gradually drying out, that's responsible for texture change. The drier the dough, the more concentrated the sugar. And a higher percentage of sugar creates cookies with chewy/crisp (rather than soft/doughy) texture.

So, enough with the science; let's enjoy one of these fresh-baked chocolate chip cookies, shall we? At the end of the day — or even after just 30 minutes — there's simply nothing finer.

Learn more: 

Cookie science: How to achieve your perfect chocolate chip cookie

Do you have any chocolate chip cookie tips to pass along? Please share in "comments," below.