Why You Should Avoid Using Old Cookie Sheets

The best cookies often have layers of flavor and texture. On the outside, they're baked until crisp and golden, while their center is soft and chewy. Admittedly, there are a lot of factors to consider when trying to achieve perfectly baked cookies, from ingredients to temperature to baking time. One thing you might not have considered is the cookie sheet itself — could using an old pan be the reason for your cookie conundrums?

First things first: It's important to differentiate cookie sheets and baking sheets. Although the terms are used interchangeably, the two pans have totally different functions. As you'd expect, a cookie sheet is used primarily for baking cookies, whereas a baking sheet can be used for roasting and baking anything. Unlike a baking pan that has four rimmed edges, Epicurious explains that a cookie sheet has one raised side and three flat edges for better heat circulation and easy transferability after baking. 

While baking and cookie sheets exist in a variety of materials, aluminum is preferred as it's fairly durable and doesn't seep into foods as easily as other materials like non-stick cookware (via Healthline). Over time these sheet pans can start to look a bit worse for the wear, but does this have any affect on your baked goods?

When deciding whether or not you should replace cookie sheets, the answer relies on the exact level of wear and tear. If sheets have warped beyond extreme, acquired scratches, or if the non-stick coating has disappeared, MyRecipes notes that it's probably best to replace them. As for stained, dull, or charred sheets, proceed with caution.

According to America's Test Kitchen, if your cookie sheets are visibly dull or dark, this can create faster heat absorption, which could lead to burning. While these weathered sheet pans can be a positive thing for browning and roasting vegetables, meats, and garlic bread, the same can't be said for cookies as they often face a much darker fate.

To avoid burnt batches of cookies, Martha Stewart suggests investing in sturdier pans that have a thicker metal gauge as they're less prone to warping. As for discoloration, using parchment paper or silicone mats can also extend the life of your cookie sheets, as will making sure to wash your pans with cleaning solutions featuring ingredients like baking soda, vinegar, and a bit of elbow grease!