Baking sheet warps in the oven

How To Stop Baking Sheets From Warping In The Oven

You’ve done the right thing and bought yourself a lovely new half sheet pan only to be disappointed to find that it warps in the oven. What is going on?

It’s a fact of physics that cookware has a tendency to warp and twist – when metal is heated it expands, this expansion has to take effect somehow and the result is often seen in warped or twisted baking pans.

There are a few things to look for when first buying a baking sheet pan that can help to prevent or at least minimise this warping phenomenon.

  • Rolled edges – rolled edges with reinforced rods can help to maintain the shape of your baking pans. A half sheet pan such as our aluminum or stainless steel sheet pans are much less likely to warp than a completely flat cookie sheet with no edges at all.


  • Thickness of material used – a heavier/sturdier sheet pan is much less likely to warp than a lightweight/flimsy baking pan. If it feels as though you could easily twist it a bit with your bare hands, chances are good that it will be likely to bend when subjected to heat.


  • Type of material used – aluminum is much more commonly used in the construction of half sheet baking pans mainly because it is much less likely to warp than other metals such as stainless steel.

It’s important to understand, though, that warping can unfortunately occur with any sheet pan, even a well made, heavy-duty one, under certain conditions. If you are able to avoid some of these conditions, you’re much less likely to experience warping with your half sheet pans.

  • Avoid abrupt or sudden temperature changes. Abrupt changes in temperature are likely to result in warping. Try gradually heating your pan up in the oven rather than placing an empty pan straight into a hot oven.


  • Spread food evenly over the bottom of the baking pan. Choose a pan that’s the right size for your cooking needs – having only a few scattered pieces of food on a baking sheet creates different temperature zones on the metal. In some spots the pan will be protected from the heat by the food, while other parts of the pan will be fully exposed to the heat. These different temperature zones contract or expand at different rates as they are heated, which will likely cause your pan to warp.

how to stop baking sheets from warping in the oven

  • Uneven heat in the oven – similar to above, if your oven has a hot spot or an area that doesn’t heat as evenly as the rest of your oven, your baking tray is being exposed to these different temperature zones. This will inevitably cause your pans to warp. There’s not a lot you can do about this one other than try out the different shelves/racks in your oven – perhaps one of the racks will have a more even heat distribution than another. Fan forced ovens usually distribute the heat around the oven cavity well, but this might depend on where the fan is situated – is one part of your baking pan being subjected to hot air more than another part?

Our stainless steel half sheet pan was invented for people who wanted to avoid cooking with aluminum, either for health reasons or for ease in washing up.

We have done everything possible to try to prevent warping occurring in this baking pan – it has a reinforced rolled edge and is made from extremely thick, heavy duty stainless steel. But, it is a metal that expands when it is heated. In some circumstances it may warp – it’s physics.

If a non warping half sheet pan is extremely important to you, we’d recommend our aluminum half sheet pan. While not infallible, this pan is less likely to warp than any baking sheet pan made from stainless steel.

Warping baking pans can be annoying, especially if your pan is brand new, but, unfortunately, thanks to physics, some movement in baking pans is normal and to be expected.
Luckily slight warping does not affect a baking pan’s cooking performance, but you do want to do what you can to try to prevent or at least minimise it.

So remember, to help stop your baking sheet from warping in the oven, cover the pan’s entire surface with food as uniformly as possible, and heat the pan slowly and gradually rather than abruptly.