I like to roast in a gas oven at 400F for extended periods. Ex: I will cook large batches of bacon at 400F for about 35 min, and large batches of Brussels Sprouts at 400F for 60+ min (with stirring). I have a large, gas convection oven.

A challenge I experience is my pans warping. This can cause them to suddenly deform in the oven, flinging food out of the pans and causing burns in the oven.

I recently got a set of 18-gauge stainless steel baking sheets, an upgrade from a thinner, cheaper set I had before. These have helped some, but I still experience warping. My questions:

  1. Would aluminum be better than stainless steel for purposes of preventing warping?
  2. Is the use of metal inevitably going to risk warping? (i.e. do I just need to give up and switch to glass or something?).
  3. Do I just need an even higher gauge (e.g. maybe 10?). (note: I like to use baking sheets that are at least 20in x 14in, and it's hard to find sheets this large at gauges higher than 18).
  4. Am I somehow missing something else entirely?

I've read that having fewer raised edges can reduce warping. But, I really need the pans I use to have all four edges raised about an inch.

  • 1
    Not sure I can formulate an answer from this info, as idk the precise specification that makes the difference - however, my cheaper [£5 - 10] non-stick 'bendy-metal' ovenware will deform in the oven . My expensive [£15 - 35] enamelled steel doesn't , ever. Alternatively, caterers seem to use exclusively aluminium with sides up to 3 or 4" deep, so that may be an option too. Maybe a rule of thumb; if you can flex it when cold, it will flex on its own when heated.
    – Tetsujin
    Commented Dec 4, 2019 at 11:03
  • I found some 16 gauge stuff that was a bit out of price target, as I'm also on the same hunt, and theoretically it's 25% thicker than 18 gauge, (0.05" vs 0.0625) so that could be enough.Generally thick aluminum will be better to avoid warping for baking sheets, but not so good for health. Toxicologists consider it a "heavy metal" because of its adverse properties in the body. Whereas steel, being primarily iron and carbon isn't really volatile for living things. High nickel content is not so good in some stainless alloys though. Commented Jan 27, 2023 at 1:18

2 Answers 2


12-gauge baking pans are easy to find, and not that expensive - you just have to look in the stores that sell to professional cooks. Search for "12 gauge sheet pan" and you'll get plenty of results. Just make sure that you check the size: a full-size sheet pan (18"x26") won't fit in most household ovens.

  • I liked this, un/fortunately for me, I am avoiding aluminum as much as possible, so it's been a challenged to find a stainless steel 12 gauge sheet pan, but I found a "blue steel" one, a bit pricey though... restaurantsupply.com/… @67USD before tax+shipping! Better than 90-120 like the two big name brand residential kitchen chains (SlT/W-S). Commented Jan 27, 2023 at 1:16

The bottom surface of the pan will expand as it heats. The edges will also expand but they won’t be able to expand as much as the bottom surface. This will cause the warping, even cracking.

As you have mentioned one way of avoiding this is having one or two edges, as the cookie sheets would have. These pans will not create such tension as the surfaces of the pans expand.

In your case however I think you need thicker pans that can withstand the tension.

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