Published November 1, 2007. From Cook's Illustrated.
The flimsy jellyroll pans sold in most stores are useless. But a heavy-duty rimmed baking sheet is an unheralded workhorse every cook should own.
Many times a day, our test cooks reach for a rimmed baking sheet. We use them for baking cookies, biscuits, scones, and jellyroll cakes, as well as for roasting oven fries and asparagus. With a wire cooling rack set inside, they're good for broiling or roasting meats and in prep work such as holding breaded cutlets before frying. Our baking sheets aren't just for baking—they are true kitchen workhorses.
But you'd be hard-pressed to find these essential pans in most cookware stores. Known as a half-sheet pan in restaurant supply stores, the real thing is made of heavy-gauge metal and measures 18 by 13 inches with a 1-inch rim all around. The closest thing you'll usually find in retail stores is a flimsy, too-small 15 by 10-inch "jellyroll pan."
Once we assembled several pans, a close look revealed that these pans are not identical. Rimmed baking sheets are formed by a machine that presses a flat metal sheet into a predetermined shape, maintaining consistent pressure so the metal will flow in without wrinkling or cracking. They can be made from different alloys and gauges of aluminum, aluminized steel (a thin coat of aluminum over steel), or a tri-ply sandwich of shiny stainless steel with an aluminum core.
After testing, we found that solid construction is more important than the choice of materials. A too-flimsy pan warps under high heat. We observed this when the oil pooled at one end of a warping baking sheet as we made fries in the 475-degree oven, resulting in uneven browning of the potatoes. And the thicker the pan, the better. A pan that is too lightweight can transfer heat too intensely, burning batch after batch of cookies.
These rimmed baking sheets were originally designed for baked goods such as cookies and jelly rolls, although the Test Kitchen has found many uses that go beyond their original design, including cooking meats (with a wire rack inside) and oven fries.
While we experienced varying levels of warping with our pans during testing, warping can happen with any sheet pan, even a heavy-duty one, under certain conditions. Abrupt temperature changes are likely to result in warping, for example, if an empty, cold baking sheet goes into a hot oven. Similarly, having only a few scattered pieces of food on a baking sheet creates different temperature zones on the metal, with some spots where the pan is shielded from heat under the food, and others where it is fully exposed to heat. Different temperature zones contract or expand at different rates as they are heated, which causes warping.
Slight warping does not affect the pan's cooking performance, however, to help prevent warping in your baking sheet, cover the pan's entire surface with food as uniformly as possible, and heat the pan gradually rather than abruptly. Using a wire grid cooling rack inside the sheet pan can help distribute heat better than cooking meats directly on the pan surface. We found a few brands of cooling racks that fit well inside our winning baking sheet (See related testing of cooling racks for details).
* Note: One of our recommended brands, Gourmet Standard, is no longer in business.