I had a set of great looking frying pans with layered bottoms that I was unable to use on my glass ceramic cooker.
The problem was the bottom would bend when heated up and lose close contact with the cooker surface. Once that happened it would take an hour to boil the amount of water that is normally boiled within five minutes – heat would just not go into the pan, so using the pan was just a waste of energy and time.
I got rid of that pan and instead used the cheapest most basic pan with single layered bottom; it doesn't bend too much and maintains contact with the surface so it works alright.
However if I want a more advanced pan than the most basic one I use now (for example, with ceramic coating), the local retailers only offer pans with layered bottoms. And of course it'll be close to impossible to return a pan just because doesn't accept heat well on my stove – that hardly counts as manufacturing defect. I'd rather not risk buying a pan if there's reasonable chance that it bends while heating up, making it unusable to me.
Is there a way to be sure that a frying pan with layered bottom won't bend too much when heated and that it is suitable for use on a ceramic glass cooker?
Best Answer
From what I've seen, encapsulated-aluminum disk bottom pans and straight aluminum pans are simply prone to warping. The aluminum is just too soft and can't take the mechanical stress, and the disk-bottom pans have problems with dissimilar metals. Different metals expand at different rates, and thus will separate over time if heated and cooled repeatedly.
Now, it's possible to get a disk-bottom pan that won't warp or separate, but the outer jacket of stainless must be quite thick, at least 2 mm. The disk in the bottom also has to be completely covered by the steel -- if you can see a different looking metal peeping out, the pan is a no-starter for you. It'll probably be a heavier, thicker pan, with fairly thick walls as well.
The simplest solution is to use a pan that's cast-iron, all-stainless, or multi-ply AKA clad aluminum/copper. Cast-iron is too thick and rigid to warp, and is a homogeneous material, so it isn't prone to problems from dissimilar metals. All-stainless is stronger and more elastic, and again homogeneous. It has lousy heat conduction though.
Multi-ply pans avoid warping because they're better made and incorporate thicker outer layers of stainless, which hold the pan rigid against warping. I think the process by which the aluminum or copper is contained in the stainless is also more robust.