Never happened to me but I am really curious as to what others come back with.

wouldn't you need to warm the pan/cool the lid if it is a matter of different rates of expansion? warm the pan to expand it (and to keep the air inside from contracting & creating a vacuum), cool the lid to contract it?

I'd say try to heat the pan up to release the vacuum.

I concur with DCMarkie. It sounds like when the pan cooled, the air inside started to take up less space, causing a vacuum inside the pan that makes the lid difficult to remove. By heating the pan (and the air inside it!) the lid should slide off normally.

I had something like this happen once, it wasn't a non-stick pan, but it was a mismatched pan and lid. Heating the pan / cooling the lid worked for me.

A matter of vacuum I should think (the lid must have been really tight), in which case heating the pan again should solve it.

Another possibility, perhaps far fetched, in the illustration the nonstick pan looks like, caphlon and the lid looks like stainless steel. Was the cook top induction? or Gas? in either case the lid could have overheated and melted the teflon causing the sticking. I don't believe that is what has happened but could be.

I have a stainless steaming insert that only fits into a nonstick pot if get the water in the pot boiling first. If I leave the insert in while it cools, it gets stuck, but if I warm the pot again, it slides right out.

I'm sure the above comments are correct (heat the pan, cool the lid), but as someone who is most definitely not a scientist, I'm loathe to play around with anything where there's a build-up of trapped air or pressure. I'd probably lose an eye.

I have a stainless steaming insert that only fits into a nonstick pot if get the water in the pot boiling first. If I leave the insert in while it cools, it gets stuck, but if I warm the pot again, it slides right out.

I'm sure the above comments are correct (heat the pan, cool the lid), but as someone who is most definitely not a scientist, I'm loathe to play around with anything where there's a build-up of trapped air or pressure. I'd probably lose an eye.

I would suggest putting ice in the recesses of the lid and using a propane torch around the rim of the pan to create a temperature differential, expanding the pan while keeping the lid relatively cooler. The coefficients of expansions of stainless and aluminum are reasonably high [17 & 23] respectively. I would not heat the entire pan - could build up enough pressure that could be suddenly released with who knows what consequences.

I'm with akay on this one. SAFETY GOGGLES! Especially if you go the ice and propane torch route!

If you use force, such as clamping the lid handle in a vise and forcing the pan handle - will likely break the spot welds holding the handle on.

First of all, there are so many good reasons to roast your vegetables instead of steaming them. I add this to the list. ;)

So. In the case of the mismatched expansion/contraction rates, the pan would have heated first, then the lid from the steam. Some of the steam might have escaped while the lid was loose, then when everything contracted together, a vacuum may have formed. But when everything went back to the default state, presuming the lid wasn't air-tight to begin with (and who steams with an air-tight lid? Hopefully nobody), the vacuum should have been released. So that doesn't seem a likely scenario.

The fusing of the nonstick material when it heated and cooled, doesn't seem that likely to me, just because non-stick traditionally isn't very, er, sticky. But I don't know how the new materials react, so maybe the new materials have a sticky state where they bond really well and a non-stick state where they aren't receptive to that. I would hope that stovetop temperatures aren't going to reach that, especially at the lip of the pan that had water in the bottom. So maybe.

Now, if the lid normally sat on top of the pan, and the lid fell down into the pan after the pan expanded, then that would make sense. Because the lid probably didn't expand or contract noticeably, and it's a much harder metal, perhaps the nonstick pan contracted around the lid and the soft metal moulded to the lid. In that case, hypothetically heading the pan up to cooking temperature would release the pan, but if there's still water in there, that might be dangerous, because you could be building up quite a bit of pressure heating the pan back up.

In any case, heating seems like the best chance to release the lid, but carefully. Once the lid is off, the state of the inside of the pan should suggest whether it was vacuum, moulding, or sticky nonstick material.

Thanks everyone! This is my pan and lid situation, and it seems like my fear of explosion upon heating is not a foolish fear?

Since I don't have a butane torch, what about partially sinking the pot in hot water and putting ice on the lid? I'm still scared just thinking about it. POOF!!

I think if you just don't put it on full blast heat for 10 minutes, you should be okay. Heat it up gently, and see if it's just the vacuum. That's the best case. You should be able to do however much heating you did to cook the vegetables without a problem, since it didn't explode before.

I highly doubt you'll have an explosion. Starting from room temp, slowly heat the pan while keeping the lid cool with ice. The lid should come off one the pan is warm, but before the lid has had a chance to heat up. As for the contents of the pan, the aim here is to only get the pan warm enough to expand it a little. Keeping the lid iced should aid in keeping the lid from expanding more than the pan again.

I doubt you can cause an explosion by heating the pan but you might want to wear safety glasses just in case. I think the idea of putting ice on the lid is good but you don't need to use a torch, it won't heat the pan evenly and you need to expand the whole pan. Just put the pan on a medium-hot burner (with the ice on the lid) and try lifting the lid every 20 seconds or so. If it's not loose by the time the ice melts you probably need to try something different.

I had this happen with my stainless steel dutch over. We tried everything to separate the lid from the pot including ice and tools. The thing that finally worked was putting it back on the stove after it had cooled. As the pot heated back up, the lid was cooler and we were able to finally get it off.

I'm going to go out on a limb and vote that it's just a vacuum issue. And if you heat the pan on the stove gently, there should be no risk of any "explosion."

Thanks a lot everybody! I'll give these a try this evening and report back with the results. Unless the explosion levels the house.

We had a similar situation at work, and we placed the 'fused' items in a hot oven (about 430 degrees) for about 10 minutes, it took care of it, they slid apart.

My parents had two pans fuse together (one inside of the other, after my dad stacked them while drying dishes). I suggested that they slowly heat them on the stove, since heat might cause the bottom pan to expand enough to release the pan that was stuck in it. It worked! Best of luck!

I've pulled a pan out of its drawer to find it in such a state. I tried cooling it and heating it but what worked was some elbow grease. I eventually pried the lid off with a butter knife.

maybe if you oil the edges it'll come off easier when you heat it up and cool off the lid. the higher pressure steam probably escaped around the edges while cooking and when it cooled, a vacuum formed inside, making it even harder to remove. wear gloves just in case it decides to pop off and the hot pan comes your way. maybe stick it in the freezer first to cool everything, and then take it out and heat the pan quickly.

Thats easy!! Allow it cool to room temperature, heat rapidly (not to allow the plate get heated-up). It is just a vacuum. Steam inside the pot will release it. This is another reason why I like lids with vent.

haha i did this when i mismatched brands of lids and pans. i called calphalon and he suggested that i heat up the plan slowly and then try to pull off the lid in increments.

It didn't work, so i googled, wrapped a can opener in a towel and hit the edges of the lid (it had suggested a rubber mallet) and it released the pressure and i got it off! put my broccoli on the other hand, was really mushy from all those attempts of heating and re-heating the pan...lol.

What happened was:
The air and moisture under the tight fitting lid was hot. When he removed it from the element the air and moisture cooled and created a negative pressure chamber (cooling air molecules got closer together) thus sucking the lid on more creating a tighter seal.

The company is right, that seal is not perfect and over time it will release; however, just putting the pan back on the stove will increase the air pressure inside the chamber and make it easier to remove the lid.

The only setback is if the lid is gouged itself into the metal, there is a risk it could explode off the top like a pressure cooker. But that's a really low risk that could result from heating the pan too rapidly.

Hey folks! So I tried everything suggested here (except the butane torch) and it still didn't come off.

One thing people seem to be missing is that the seal formed while the pan was still on the burner, there was no cool off time to create the vacuum so I'm wondering if it is something else; something chemical.

I haven't tried the mallot solution though ... that seems fun! I'll give that a shot tonight.

Thanks again y'all!

Probably unrelated, but working at a bicycle repair shop we see fused-metal situations pretty frequently. Aluminum and steel will fuse together if left in tight quarters without any grease (lube everything, people!). The nonstick coating of the pan presumably would have prevented the metals from chemically fusing to each other. However, I have no idea what the coating is made of or if it could have been the culprit.

This happened to me once, and we finally gave up trying to get the lid off. Then, out of the blue 3 days later, we heard a noise and the top of flown off the pot and landed on the floor many feet away!

I'm a day late and on the money. When I saw the photo, my first thought was that the lid vacuum sealed to the pan, which was confirmed in the update. If they really want it separated now, my best suggestion would be to drill a small hole in the lid and be careful to keep the lid weighted down during the process so it doesn't fly off when the pressure is relieved. This small hole will not only release the pressure, but also work in the future to keep it from happening again. A small enough hole near the perimeter won't significantly affect the ability to steam veggies in the future.

I have Cuisinart pans that are basically a knock-off of the Calphalon pans. The manual for them says this might happen if you put the lid on a hot pan then let it cool without removing the lid. They say to reheat the pan and it will come right off.