Here's Why Baking Sheets 'Pop' In The Oven
Anyone who's baked a sheet pan of cookies has heard it. All of a sudden there's a tremendous "bang" from your oven. What happened? Did something explode? Are your cookies ruined?
Nope — your baking pan popped in the oven, and now, it's warped and crooked. This happens for several reasons. The first is something called thermal stress, per Science Direct. Metal expands when it's exposed to high heat, particularly if the temperature change, as in from room temperature to the heat of the oven, is sudden. This stresses the metal so it's more prone to warping. Second, because no metal pan is completely even, some parts may expand more quickly than others — and it pops and warps.
While your cookies will probably survive, the pan itself is now a problem. Can you fix the pan? Should you use it again? And can you prevent this warping in the first place?
How to avoid warping
Now that we know what causes this banging and warping, is there anything you can do about it? According to Cook'n, yes.
First of all, don't buy flimsy cookie sheets and rimmed baking pans. They're far more likely to warp and pop in the oven. Look for heavy-duty steel pans that are solid and have a nice heft to them, suggests The Strategist. Buy sheet pans with a rolled or rimmed edge, too — the support makes the pan more stable. Cook'n adds that those pans are made by pressing steel with consistent pressure so there are fewer weak spots. Second, don't put a baking pan or cookie sheet in the oven unless it has quite a bit of food on it. Try to cover the surface with food and cover it evenly.
America's Test Kitchen adds that bare spots in the pan heat more quickly than spots with food on them, which is why a nice, even covering of food is the best choice. And when the pan is out of the oven, you can save further warping by not rinsing a hot pan in cold water, according to Martha Stewart. Let the pan cool first, then wash it.
Can you fix a warped pan?
There are multiple ways to fix a warped pan. But if you can't fix a damaged pan, throw it away. Warping will expose the food to slightly different temperatures, resulting in uneven baking. And if you're baking something that releases oil as it bakes, the oil will pool in one corner of the pan, ruining your food and presenting a hazard when you take the pan out of the oven.
To fix a warped pan, put it in a low oven (about 200 degrees Fahrenheit) for about 10 minutes. Then gently hit the wood with a mallet until it's straightened out. (It may be best to do this on the floor of your kitchen or the basement to protect your countertop.) You can repeat this process as necessary until the pan is straight. Then add another pan weighted with some heavy cans or books on top as the pan cools so it holds its shape.
Once that's done, use your sheet pan to make these fabulous sheet pan dinner recipes.