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We recently bought a flat top (glass top) stove to replace our standard electric stove with the coiled "eye" heating elements. The flat top is certainly easy to clean, and if you have a boil-over, it does not fill the pan under the burner and spill into the interior of the stove - all pluses. However, I find that every nonstick fry pan I have has developed a 'bow' or curvature. That is, the center of the pan is bowed out, so that when the pan rests on the flat top stove surface it does not make great contact anywhere except right in the center. All the edges of the pan curve up, away from the heat. Thus it takes awhile to heat up, and probably wastes lots of heat. This bow may have been present with the regular "eye" coiled heating elements, but it wasn't as noticeable because they were not as absolutely flat at the glass. I even bought a new nonstick skillet, and swore to never use it on more than medium high, to keep this bow from forming. Still, it has bowed over a few months use, so even on the new skillet this problem remains.

My question is, what can I do to avoid or fix this problem? I keep wishing for some high heat tolerant and conductive thing to put between the stove surface and the pan so I get good thermal contact (something like a thin bag of sand, but with the bag made out of a material that would not be destroyed by the heat). Or am I just buying cheap nonstick cookware, and if I really spend a lot on a frying pan, the problem would not occur. This last part is really my question. I have spent $30 on a frying pan, only to see this same thing occur. If I spend $200 on a frying pan, will that solve the problem (will it not do this bowing thing), or will I get the same results in a few months? In case it's relevant, I live in the US (North Carolina).

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    One more tick in the "I do not want one of these glass-top stoves" column.
    – Ecnerwal
    Dec 10, 2016 at 4:45

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The reason that cookware warps is that it is has too thin of a base. When it has been heated to a high temperature, it warps upon cooldown. The only way to avoid this is to buy very sturdy, heavy duty cookware. You need to look for something with a very thick and heavy base, then you will have no issue.

And don't think that it will put you in the poor-house. I bought new pans 6 years ago, and they are still fine. The most I paid was $30 for my 14 inch pan. Every other pan I bought on sale for 10-15 dollars.

As for pots, you should be able to get a good set of Lagostina (or comparable brand) which are certainly not professional, but they will do the job. They will not run too much money.

Just reread your post, originally missed the bit on the end. You absolutely do not need to spend 200 dollars on a pan. Just do your homework on the brand you are buying. Where do you live (country, I mean. Not trying to be too personal)? I may be able to suggest some places if you live in North America.

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    He added a comment to the Question that says he lives in NC, by the way.
    – Preston
    Nov 24, 2014 at 1:25
  • It's 2021 now and you can buy those korean stone surface pans, they got thick bottom, does not warp and the non stick is awesome, lasts a long time. I cook chinese food and use of cold water on a very hot pan often occurs, cookware stays perfectly flat after use.
    – Huangism
    Oct 2, 2021 at 2:10
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Ensure that you're not washing them until after the pan has cooled - the cooler water can cause warping if you do like my fiancee and take them right off the heat into the sink to soak.

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    You can wash them warm, but you don't want to give them a sudden thermal shock. (a small amount of liquid to deglaze should be okay, but not tons of water after having had the pan blazing hot). I prefer washing them warm, as I find it easier than letting them cool down fully first. And like mrwienerdog mentioned -- heavier pans will have less of a problem than thinner ones.
    – Joe
    Oct 24, 2011 at 16:35
  • Right, I was referring to the practice of plunging them into lukewarm or cold water from the sink immediately after removing the cooked food, while the pan is still at its hottest.
    – Yamikuronue
    Oct 24, 2011 at 16:39
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    It's been 9 years. Is she still your fiancee? I see this as a deal breaker :/
    – Madis
    Sep 10, 2020 at 18:42
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    lol no, we're happily married and own our first home together at long last. And our pan bottoms are flat!
    – Yamikuronue
    Sep 11, 2020 at 19:07
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This most frequently happens with thinner pans used on too small of a burner.

Effectively what you're doing is heating up the center of the pan so that it expands, but the outside edge hasn't heated up yet. As the center can't go out, it goes up (or down).

You either want to make sure that you're using an appropriately sized burner for the pan, or you can try pre-heating the pan over low or medium heat. It also doesn't help that some of the heat will conduct up the sides of the pan, keeping the outer edge cooler than the middle.

... there's also a chance of this happening with stainless steel pans with a disk of another metal attached to the bottom, as the two metals expand at different rates ... but in that case it's a problem with too high of heat over the whole surface. Tri-ply pans (where there's stainless wrapped around both sides of the thermal core) reduce the problem, but they're quite expensive.

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I have one large, deep sided skillet, which bows upward like that. I'm very careful not to shock the pans, but this one is very thin. The other pans I have, with thick bottoms, don't move at all.

I got into the habit of putting the tea pot on, while cooking. This is partly because I'm usually also making coffee, and I use the hot water to warm the cup while the coffee is brewing. As a side effect, if I want to add some water to a hot pan, I have boiling water to use. Hope it helps.

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Aluminum likes to bow as you describe. If you lack any good hard surfaces in the kitchen, take the pan outside and whack its bottom on the sidewalk a couple times. That'll reflatten it. Carefully aplied hammers or fists can accomplish the same job inside.

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You propably need new pans. To keep them from warping like your old ones, follow these simple rules:

  1. Use a heating element that is at least as large as the bottom plate of the pan.
  2. Pre-heat all pans on a really low setting before cranking up the heat. Don't heat the pan empty whenever you can avoid it, and no hotter than necessary. (This will also extend the life of the coating)
  3. Allow the pan to cool on it's own after use, only wash after it's not too hot to touch anymore.
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    Actually, "at least as large" is not good enough. If the pan is prone to bending, its center will bend inwards when used on a too-small element, and it will bend outwards when used on a too-large element. You need something that is the exact size.
    – rumtscho ♦
    Jan 23, 2018 at 9:19
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Ensure that the thickness is 8 mm or more; the curvature occurs in pans less than 5 mm tick, in my experience.

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