Will a induction cooktop warp your cookware? 

Engineer here. I can tell you exactly what's going on with cheap induction plates. Devices like this where you just plug it in and it outputs energy, be it a cooking hob or a panel of LED lights, use a thing called pulse width modulation (PWM) to control the output level. It can't turn it on half power, the output is always gonna be 100%, so what it does is just turn it off half the time. So over the course of the cooking time, you have a controller just flicking it back and forth from completely off to completely on. In a high quality device, that's fine because it can do it several times per second and the pan behaves normally, hence your lack of issues with your main cook top. Introduce a cheap pan with cheap components (like my Tefal that I also only use to boil water) and you end up with a much longer period of time switching on and off for one of a few reasons: either they hired a bad software engineer to program the thing (not likely, this is "engineers fresh out of college know better" level stuff, and all the cheap ones have the same issue); they installed an induction circuit that can't be switched on and off very fast without taking damage; or they used the cheapest chipset possible to squeaze a profit out of the thing (this is what I suspect is the culprit) and this is just the best it can do. So what you're seeing is the pan going on full blast for like 30 seconds and then turning off for maybe 10 to 20 seconds, then repeating the cycle. You can verify this in a quiet environment by just listening to the buzz of the cooker cycling on and off. So even if you're only turning it to 5/10, the pan is experiencing 10/10. If you want a visual, I am sure there are a ton of RU-vid videos on PWM, it's a really important topic for us.

I have used little induction plates and my stove’s induction cooktop for years. I often used high heat on the plates, stir-fries, searing meat, and boiling water quickly in a steel kettle. Never a problem. Watching your video I was reminded of the instruction on all of them. NEVER power on an empty pan. Even stainless steel may warp when heated dry, on induction or a campfire, and hitting a hot pan with a lower temperature can warp it too. So in my opinion your video was a success and I am going to get a carbon steel skillet!

Tiny ~5'' induction coil, terrible power regulation => warped skillet. The typical standalone induction stoves over here are usually around 2500-3500W. The tiny coil creates a hot spot in the center of the bottom which then expands, the surrounding material is much cooler and doesn't expand at the same rate. Therefore, the hot spot can only move up or downwards => warped skillet. It's nothing but physics. Use a decent induction stove with larger coils and good power regulation (as many real power levels as possible + short cycles). Only use a skillet with the bottom size equal or smaller than the true coil size. Pre-heat slowly. Never use the power / boost / quick boil funktion. Tadaaa - no warping issues.

The less expensive the induction burner the smaller in diameter the electromagnetic element. They seem to typically be about 6 or 6.5 inches. If you put a pan with a bottom that is larger in diameter than the diameter of the induction coil and you use a higher heat the area of the pan inside the 6.5 inch area will be at a very high heat and the area outside of the 6.5 diameter area will be much lower heat because it's not being heated by the induction element. This heat differential can warp the pan. You can see the small size of the induction element when he puts the water in the pan. The induction element is causing the pan to heat only on the 6.5" area and not outside it. For example if you cook something like a pancake or rounds of sliced zucchini covering the full size of the 10" bottom of a pan on the 6.5" induction element you will see that the pancake or the zucchini rounds will cook over the 6.5" element area and much less outside that area. Gas cooking is using flame contact to heat the pan and it laps up the bottom and sides unlike induction. The higher end induction cooktops have much larger induction elements. Some are 9 or 10 inches and therefore the cook over the entire bottom of much larger pans. I am sure that the way the electronics modulates the magnetic pulses to the pan also enters into it. The higher end products have larger more expensive elements and more advanced electronics.

One note.... the "spin on a surface" test would only show warping if the pan has warped in a convex shape (bottom bowing down). However it won't do that if it warped in a concave shape (bottom bowing up). You would need to put a small amount of water into the pan to see if if flows away from the middle. This kind of warp could potentially decrease the efficiency and uniform warming of induction cooking.... which you actually saw into the video.

the reason for pan warping is do to the size of magnet in the induction cooker if it's smaller than the pan then it's not heating up evenly 9 in pan needs 9 inch magnet the bigger the pan then you need a bigger magnet or it just heard Sefton parts of the pan and most portable induction tops only use 7 inch magnet hope this answer makes sence

I have one of the Nu Wave branded induction cooktops, and tried using it with my 2mm carbon steel wok. My flat bottom became a round bottom before the temperature went to 375. I freaked seeing the severity of the warp that fast, at it aside on one of my electric coils to cool and just ended up cooking there, my room is WAY too important to my household to abuse like that. Thankfully, she was properly tempered and returned to shape as she cooled, so I just cooked dinner there instead. I have used that burner with my cast iron and while the temp you set it too never matches the temp of the pan, you can use a thermometer and still get consistent heat for shallow drying or boiling. But yes, I think these cheap induction cook tops are not evenly applying the magnetic field, that's where the warping is coming from. That's Aldo why the wattage is still a factor desire being lower than the real build ins, the quality of coil is the problem, it's not getting electricity evenly across the coil, so it unevenly heats the pan.

One thing to note, is that you only checked one type of warp debuyer pans and others, have an upward bow from factory so that if it warps, it would have a higher tendancy to warp upward, and thus would not rock on a flat surface But at some point the oil heavily running to the sides can be quite annoying. putting something straight like a ruler / rolling pin on the bottom of the inverted pans would have been more accurate to judge the changes

My DeBuyer skillet was flat when cold. But when heated on either induction or electric ceramic hobs it spins when at the ideal temperature. When cooling down it was flat again. I had to deform it by putting the pan upside down on a flat surface and bash the centre of the pan with a heavy wooden log so when cold the centre is pointing up a bit. But when at cooking temperature it is flat and if too hot it spins. This put me off buying anymore even though that one pan performs ok for me now. Induction performs ok even if you lift the pan 1 mm but electric cooking plates rely on contact and will be negatively affected.

I had cast iron pans that got split in two on induction top plate twice. But never on regular induction oven. I was told it's because the power in the top plate send higher current through less efficient low quality magnetic coils.

It warped my ALL CLAD tri ply clad fry pan. I have never mishandled any pan in my 60 years of cooking because I treat them properly.

Cheap ones have heater diameter smaller than the pan. You can't see it under the glass. So the middle the pan gets hotter than the sides and that heat will never be even throughout your cooking. That's where the warp happens when it cools.

In case it matters.. uncle Scott’s kitchen had much worse results.. I suspect the individual units vary too..

My 4 liter Demeyere pan warped and became a spnner. I have a Siemens high end induction stove top and naturally never submit my pans to temp chocks. It got replaced under warranty but the new lid doesn't fit as snugly. Bit disappointed.

the problem is not cheap induction plate the problem is small magnet diameter use a smaller pan it will never warp

I don't think most induction owners even know their cookware is warped. Like you, they put a pan on the plate and if it gets hot, they roll with it. For me, I don't like warped cookware. I have seen this in my mom's cookware and I can't stand cooking with it. It's all up to the individual how much damaged goods they are willing to tolerate (or some are totally ignorant of.)

I think the easiest solution would have been to use a reference straight edge. It would give you a bit more of a quantifiable effect.

Nice concept, but it does look like you’re seeing the same non-centered spinning with the pre-heated spin check. Technically, they shouldn’t spin around the center of the pan anyway because the handle changes the center of gravity away from the center of the pan and towards the handle. I also noticed that the post cook top warping test was only done with one hand on the handle and the other directly across from it, not the diagonal test that you did post portable cooktop testing. I don’t blame you, btw. You learned how to identify the warping after the tests were finished. I only pointed it out because the results are suggestive, but the testing wasn’t completely the same. Good video though. The tests were performed as well as you could expect an initial test to be performed. It’s not to say that the pans aren’t warped, just that technically, the test should be repeated to increase the rigidity of the findings.

Great info from all

Well, you can always use your warped pans on a gas range....

Yes pans (stainless & carbon steel) can warp. The thinner the metal the worse the warping. Pans can warp inward or outward. Doming inwards so oil runs towards the edges. Warp outwards so the pan spins and/or teeter totters. So what's causing this? It's you. You don't know what you're doing. If you're using a plug-in induction cooktop don't put it on high heat/10 with nothing in the pan. Rapidly heating the pan will definitely cause it to warp. Start on power level 5, IF you need more heat increase it from there. These are general settings for induction cooking and your cooktop may very. Keeping food warm/simmering power levels 1-3. cooking food/solids is power levels 4-7 Anything past 7 is for liquids, reducing stocks/sauces, soups, and boiling water. Water boils at 212° F so if you have the pan cranked up to 10 your pan isn't going to get hotter than around 250°, cause the water inside is keeping your pan cool. But if you're grilling onions on 10 because you're brand new to cooking and you have no idea what you're doing, you're going to scorch your pan and probably warp it as well. Can a warped pan be fixed be? Yes. find a hard flat surface like leveled concrete or an anvil if you got one. And get a rubber mallet or a plastic dead blow hammer. And hammer it flat. If all you have is a regular steel hammer, put a piece of dense hardwood inside of the pan so you don't completely marr up your pan. The thinner the pan the easier it will be to get flat, the thicker pans you better be swinging hard. Also find a straight edge/steel ruler to check for flatness. There shouldn't be any gaps (ideally). Also It doesn't need to be dead flat, just flat enough to where your happy cooking in it. Don't overdo it. If you're brand new to induction I personally recommend the Duxtop 9100MC, it has an anti scorching feature that helps prevent you from completely fucking up your shit. It also 2 readouts, ot has power levels 1-10 and cooking temperatures between 140°F-460°F so you have a lot of temperature control. It's basically idiot proof.

I have a 4000$ Samsung cook top and it still wrecks pans, mostly on the massive burner , I think because it has two coils, small inside and a bigger outside coil,

I wish I saw this earlier ... I feel sad...

I’m pretty sure it has to do with how quickly the pan heats up. My Misen 12in carbon steel pan warped within a few weeks of owning it using my Monogram Induction cooktop. Here’s a video of it. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-8M2dBDCUVuA.html

lodge 10in carbon pan paperwork say's heat slowly on induction not to warp pan That's how I do mine no problems. Using some cast iron and carbon steel for 65 years . I have cast iron from my family's farm . Built in1690 york , maine pots and pans go with the farm when it goes to the next family member. I was born in it, we all where!

Great topic for a video. We have an electric stove top, not induction. I've had no warping on my de Buyer 9.5" Mineral B. I also have a 11 7/8" Matfer, which has warped and spins, and I can rock it. At first it only warped when I cooked with it, then went back to flat when it cooled down. But now it's warped permanently. The Matfer is larger than any of the hobs we have, so maybe that's why.

What is the model and brand of your cooking stove? Not the portable one

Why would you have to pre-heat the pan with induction?? Isn't induction supposed to heat the pan instantly??

As a general question, the answer I give is NO, it does not warp my utensils. And I have a GE Profile induction range, which has a very large main induction coil passing a large current into a pan, particularly if the “Power Boil” setting is employed- it is quite audible. All my stainless and cast iron has done quite well in the 6 years we’ve owned the stove. I own no carbon steel cookware, so I can’t speak to that.

Great video, as usual. 👍 One thing I would have liked to see was letting the pan air cool after grossly overheating. Just leave the pan alone until barely warm and then test to see if slow cooling allows the metal to resume its original shape. I just wonder if shock cooling under water ruins the pans' ability to recover. Likely not I guess, but it would be good to verify... with your pans, not mine ;>)

I have a food network cast iron. I used an induction burner and now there is a C shaped mark just outside the center of the pan. And the center isn’t flat. I’m pretty sure it was before I cooked with it. The cast iron was a gift and came pre seasoned, didn’t realize that was a thing.

My husband and I borrowed one of those cheap induction hot plates from my parents to see if we liked it enough to replace our gas stove with induction. We liked it at first but now, after a month or two of using it as our main burner, our two main pans are warped. His 10” carbon steel is warped outwards and rocks on a flat surface, while my beloved 12” all-clad is warped inward so all the oil runs to the sides. I suspect, as you suggested, that the warping has gotten worse over time with repeated use. Good to know that we might not have the same issue with a “real” induction range.

And this was a single test, at not even the max heat! Imagine doing this many times and cranking it to the max, which is probably not uncommon for people who think “induction is super fast to preheat, so I’ll just do it on the max for a minute to sear the food, and then turn it down to cooking temp after that”

Yes, yes it will. My matfer and my stargazers both did (and regained their shape after cooling).

Thanks, Jed. Great beginning and I look forward to further studies/info on your part.

I have has a Miele induction cooktop for over 15 years. It would turn itself off if it overheated the pan, from being left on 8 with nothing in it.

I think the warping is more an issue with thin carbon steel pans and also new pans that are possibly not as able to take temp fluctuation and a pan that has been heated and cooled many times.

Hi, Have you tested Warping using a Glass Infrared Cooktop? I've warped a Stainless Steel Frying pan and pot. My cooktop is rated at 1800 Watts.

Take your pan to a shop with a press and take the warp out. Won't work with cast iron but will with low carbon steel. Use a straight edge to check for warp.

Good cooktop with a great coil size.

the big problem I have is that induction bloats my pan from the middle outwards. And so what little oil I add goes to the sides of the pan.

Has anyone had the same problem with electric ceran glass cooktop? I wonder if the on/ off thing described above for cheap induction cookplate also happens in electric glass cooktop? We recently had a brand new high end cast iron pan ending up bowed after using it on an electric glass cooktop. The electric cooktop is also new ( not our choice, rental unit) and I bought the cast iron as a xmas gift knowing that we are getting a new induction cooktop in our new kitchen soon. We just could not understand why a cast iron pan would bow like this.

Have had this problem with cheap aliminum pots and pan s its not warped. The pan handle in my case was heavier than the pan and lifed up at 10 deg and would spin if pushed. Hope it helps

So you refused to really test. If you really test then you would have used 10 for 4 hours. I DONT CARE THAT YOU DONT USE THAT. Its a test on what people use. AND YES ON 10 FOR 4 HOURS IS COMMON. If you are pressure canning above 3000 feet. It takes 1.5 hours until pressure is up. And another 1.5 hours for the process. So really the test should be 10 @ 4 hours. So you know it safe.

So... I used to have a very expensive high-end induction range and after ruining (warping...) almost a full set of All-Clad D5 stainless steel, two De Buyer carbon steel skillets (8" and 11"), one 12" Lodge cast iron pan and one 12" Jamie Oliver Pro line non-stick pan, I started to wonder WTH was happening. I started asking questions. Then my 6 year old induction range started acting up and one of the eyes became twitchy and unreliable. So I called a repair man to fix it and when he saw the range, he refused to get anywhere near it or any induction range whatsoever. With 30 years of experience behind him as a repair man, he told me that induction technology was not quite there yet, and that the only way to actually "repair" induction ranges was to replace the whole top section! He also told me that he was not going to get involved with replacing the top section of my range because of too many bad history around induction repairs and it's unreliability. So, he left and that was that. Then I called the company that makes that induction range, told them about the "symptoms" of my unit and they said the same thing, that they would have to change the whole top section of it. Then I was made aware of those famous "issues" around induction range and warping. So I called my brother in law who'd just bought his induction range a year prior, and he also confirmed that his cookware now had either a raised spot in the middle, or a lower spot in the middle, which causes the spinning on a flat top. Then I asked around at work and friends that had induction ranges and all 6 of them confirmed that their cookware had been warped or the center raised (making the melted butter or oil slide slide away from the center and just sit on the outer edge of the pan, leaving the center uncovered with the fat or liquid...). So anyway, that happened a little more than 5 years ago, and that's when I switched to gaz and never looked back. I actually took that stupid $2800 induction range out of my house and left it out on the side of the curb along with the garbage bins. Gaz IS better, gaz is the cat's meow! It cooks better, it seasons better, it responds better and quicker to heat changes and --- it doesn't warp your cookware. All this to say, last week I went to your store in Vancouver and purchased two of the used pans (the ones you used in your cooking class program that you don't do anymore -and that's unfortunate...). They were 2 De Buyer carbon steel pans, one 8" and one 11", and BOTH have a raised spot in the middle... I don't care that much about that defect because I got them for our little kit we take with us when we go camping. But those 2 pans, especially the 8", is quite warped... and you used those on your induction-equipped kitchen at the store. So, I don't think it's that simple, and an extensive history of testimonies from so many induction flat top users should carry more weight in this debate. I never used a small induction pod on my cookware because I never had one. My expensive cookware was damaged by that induction range. But now, with my gaz range, my new set of De Buyer carbon steel pans I got (...also from your store...), are still as flat as they were when I got them a few years ago, and I use them every single day. I also have Matfer Bourgeat pans and got the new All-Clad copper-core kit and I gave away all my older sets of pans and skillets to my niece, along with all the non-stick pans I don't need anymore (and don't want to use them anymore). I also told my niece to get a gaz range... In the end, my conclusion is clear. Induction systems, either flat tops or pods, expensive or not, may very well warp or damage pans and skillets, and gaz just simply won't.

Please kitchen tour😇

ironically, this guy always looks like he needs to eat a nice steak

i have had my DeBuyer CS turn into a spinner on our Thermador induction cooktop. Not a portable cooktop. Just fyi. Moving to the Thermadore freedom cooktop for our kitchen reno so hopefully doesn't happen again. This happened searing steaks on high power boost level. Its not a slight spin, its a full on spin and has never gone back to original shape. Also , i think the warp is cumulative after several uses.

It would have been informative to use a laser infrared thermometer to see if there were hot spots on the pans. Or just plain see how hot the pans were actually getting. These thermometers only cost $20 to $30 and would give more “scientific” insight into what might actually be happening. How similar were the actual temperatures of the pans on the different plates? How even were the temperatures spread out over the pans?

Interesting experiment, but one "cook" to me is not enough to merit results as these are supposed to use over and over. Slight warping over and over and over may make pans unusable. I know my electric stove will warp pans.

I wonder if the direct sense induction hobs work better. Instead of measuring the glass temperature, they measure through the glass with laser like the temperature guns or with an actual sensor in a through-hole.

I always use a mallet to flatt the bottom out. Just put it upside down an a massive wooden board and give the elevated part of the bottom some strokes until it's flatt .

I had a lodge cast iron griddle crack on our induction stove

Solution, buy a heat diffusion plate for induction stoves = no warping anymore. As a big bonus you can now use *any* pan or pot, including glass, with your induction stove, since the diffusion plate converts the magnetism into heat so the pan/pot don't need to do it.

I just bought an induction stove from Lowes (not a cheap induction plate) and had it installed this weekend. It instantly warped my largest frying pan. I turned the stove on and 2 minutes later I smelled something burning, turned around and saw the bottom of the pan was glowing red it was so hot, and it had warped immediately. Not only that, the stove makes a horrible humming sound when it first comes on that gives me a headache and makes my poor dog run and hide under the bed. It’s going back to Lowes and I’m going back to gas. If I ruin an entire set of expensive cookware, over time it will cost more to repeatedly replace the cookware than to replace the stove.

hi jed, which manufacturer is your big built in induction hob?

Thanks so much for the great informative content on carbon steel! have you ever compared the de buyer mineral B pans to their Carbone plus? They look near identical but I cannot really find anywhere what the differences are and if they truly effect performance. There is a difference in price, the Carbone plus are cheaper but I have no idea if this means you are missing out on something i.e. slightly lower quality? different material? if you have any idea I would really appreciate any answers

Have you tried Aus ion pan?

Heat is the same and has the same effects no matter the source of the heat.

Some more carbon steel garbage