I am a complete amateur when it comes to the world of cooking.

My recent attempts to teach myself have unfortunately lead to me needing to ask:

How did I explode my saucepan?

I'd put some garlic/onion/olive oil in the saucepan and left it on low heat to soften on my electric hob. After about five there was a loud bang and I turned to find the saucepan falling through the air (which I just caught by the handle). The base of the saucepan had come away from the body. Cue jokes about taste explosions from my flat mate

I am fairly sure this wasn't supposed to happen.

The same thing happened when I was cooking meatballs with some onion on the side - though to a much lesser degree.

Did I just have a duff saucepan, or is there some explosive quality to onions I missed!?

On the plus side, the meal came out okay in the end.

  • 8
    I've never heard of this happening before. Now, despite being a beginner, you have a cool story to tell which will surprise and amuse more experienced cooks. To me, this alone would be worth having to replace the pan with the freak malfunction. Although I can understand that it probably didn't feel amusing when it happened and you were afraid you'd done something wrong, looking back you can laugh at it.
    – rumtscho
    Commented Jun 12, 2015 at 13:31
  • 1
    This is a regular conventional electric or ceramic element, right? Induction hobs can heat a pan vigorously, and certain pans are much more appropriate for induction elements. I've never heard of this, though, either! Was the pan or base warped, and did they come completely apart? Any other noteworthy markings? Picture?? :)
    – hoc_age
    Commented Jun 12, 2015 at 15:03
  • 5
    Also, nice catch, although it would have really sucked if the pan had been hot enough to burn your hand. Commented Jun 12, 2015 at 23:47
  • 21
    Following on from @KyleStrand's comment, do not attempt to catch things in the kitchen. If it's a hot saucepan, you risk burning yourself; if it's a knife that you've dropped, you risk losing fingers. Get out of its way and let it fall to the floor. Commented Jun 13, 2015 at 11:25
  • 15
    I'm a chef. You had a crap saucepan. And as David said, NEVER TRY TO CATCH THINGS IN THE KITCHEN! I was on a cooking course in Ireland. A girl dropped her knife, and tried to catch it because it was pretty expensive. She severed all the tendons in her forearm, almost bled to death, and needed reconstructive surgery.
    – Wad Cheber
    Commented Jun 15, 2015 at 6:52

7 Answers 7


I work in a commercial kitchen and I've seen this happen before, which is why we do not use copper-plated cookware. This can happen whenever you have two different alloys welded together and apply heat to one side or non-uniformly; An effect known as 'thermal shock'. What happens is one metal expands faster than the other, causing a deformation or fracture. Think of it as one side trying to 'pull' the other at the edges. The pop you heard was undoubtedly this delineation occurring, followed by the kinetic reaction of the pot jumping.

I find your claim that the pot leaped through the air difficult to believe, but I have observed audible pops and visible movement when they fail. If you have a flat top (like an electric stove), it could skid for up to a foot from this due to the lack of friction and possible presence of condensate (water) on the surface which can at certain temperatures act like a nearly friction-less cushion. Oil doesn't do this, only water.

If you've ever been in a commercial kitchen you'll notice every cookware item is made of a single cast of metal (most usually stainless steel) because of this. Welded alloy pots and pans just don't last very long -- the effect observed so violently happens at a smaller scale with every heating cycle, eventually resulting in ruined cookware. Also, being a line cook means being exposed to things exploding, dying, catching fire, etc., on a near-daily basis, not to mention an assortment of knives that would make most Hollywood bad-asses blush, so obviously we try to limit the number of things that can go wrong.

Do yourself a favor -- if you stick with the copper-bottomed pots and pans, make sure to put plenty of water or oil in them. Heat with nowhere to go will cause failure quickly.

  • 1
    When I say it was falling through the air, it'd come off the oven. Can't say I saw how it came to that state! Appreciate the explanation and confirmation it's not my terrible skills or exploding onions. Looking at the pan that this happened with on a smaller scale the copper has come partially away on the bottom from that incident!
    – JoshuaMee
    Commented Jun 18, 2015 at 11:41
  • Stainless clad to carbon steel can tolerate many cycles of 800 F to room temp water ( testing for pressure vessels) . I expect copper cladding could do the same. Commented Oct 17, 2018 at 22:14
  • You can get "bimetal disks" in some science museums. They're two metals laminated together, but with different thermal expansion properties. They were concave, and as you heat them up, the expansion differential would cause them to pop and go concave the other way. As they cooled off, they would pop again, and go back to original shape ... but the force was enough that it would leap into the air if it was set on a table. It's possible that this is what's happening.
    – Joe
    Commented Jul 30, 2020 at 15:15
  • And some video of a bimetal disk jumping : youtube.com/watch?v=Lhv9W5B3ITc
    – Joe
    Commented Jul 30, 2020 at 15:45

If your electric hob is anything like the one I had when I was younger, it has small rings in the metal of the hob top.

If the pan was wet, the water can pool there and become superheated, until the weight of the pan isn't enough to contain the force of the expanding steam. At this point, the pan jumps, pushed upwards by the steam. If the pan is cheap or old, the force of the jolt might be enough to break it.

My pans used to dance on the hob when wet, as the steam let off in small amounts all around the hob. After a few minutes, the water would be gone and the pan would sit normally.

  • I've never seen these in the US - other than the expensive ceramic ones, all our electric stoves use coil elements. Are they common in the UK?
    – Random832
    Commented Jun 12, 2015 at 21:00
  • @Random832: In older properties, yes. Commented Jun 14, 2015 at 17:38
  • 1
    @Random832 Just to confirm this was a common feature of older cookers in the UK. I can remember my family having one as a boy, and at least one student flat I lived in had one. That said, I've never heard of leaping pans being a possible result.
    – Bob Tway
    Commented Jun 15, 2015 at 13:09

(if I understand correctly)

You probably used a cheap and very thin saucepan, and on the heat the metal expanded and had stressed to the point of failure, it buckled and acted as a spring.

  • 3
    Some electric stoves have 2 states, on or off, ie full power and no power. A low heat setting means you have less frequent pulses to full heat. This means that pans are getting heated at full blast even on low. I would suggest getting some thicker pans.
    – GdD
    Commented Jun 12, 2015 at 13:17
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    I see this often with cheap baking sheets, also. The loud clang from the oven still freaks my dog out from time to time.
    – Geobits
    Commented Jun 12, 2015 at 17:27
  • @Geobits That scared the crap out of me the first time it happened with baking sheets. Quite a bang with larger sheets! Commented Jun 12, 2015 at 22:49

I've seen similar things happen with the flat kind of electric hob with the little hollow in (this kind: https://commons.wikimedia.org/wiki/File:Electric_stove.jpg )

This can happen when the stove is wet. If there is water in the hollow when you put your pot on it, and the flat bottom of the pot closes the cavity, the water underneath will start to boil. If the stove/bottom of the pan is also oily, it can stick to the stove.

When the water in the cavity starts to boil, it will rapidly expand. With nowhere to go, it's possible for a pot to go flying when that happens. This is not, as you already had a gut feeling about, supposed to happen.

If it does happen though: Don't catch it. The best thing that comes from that is that you can say "hey, did you see that, I caught it". More likely scenarios involve burning yourself or cutting off fingers (for knives).

When things fly through the air, it's likely you're going to have to clean the floor even if you catch it.


Not so much "plate tectonics" but "pot and pan tectonics". This is likely a manufacturing defect. The thermal expansion answers are correct, a sudden shock occurred when a "critical point" was reached and the base has sprung back into its "relieved" state. (I do not think there would have been enough heat for annealing to be a factor.)

As for super-heating, water will "knock" if superheated and detergent is added (or any surface active agent). But normally ceramics or stoneware is involved (something with vertices).


There are many companies which produce glassware that is safe for the oven. Although many of these products resemble sauce pans or skillets, they really are casseroles for use in the oven. If you place them on an electric eye or a gas flame, within a minute they will explode into tiny fragments, usually leaving the handle behind.

I had purchased a rather expensive version of these some years back and my roommate did this, not once, but at least 3 times, ignoring the large embossed letters on the pan: "NOT FOR STOVETOP USE"

  • "The base of the saucepan had come away from the body" suggests it wasn't glassware of any kind that failed... Commented Dec 14, 2016 at 10:29

yes this can happen, its caused from the saucepan being placed into cold water over time, the sudden temperature change from very hot to cold causes decontamination (the saucepan to heat sink / copper base ) partially separating allowing water to enter, once the saucepan is heated again the trapped water turns into steam increasing its volume by 1000 and going off like a bomb.

  • 2
    "decontamination" --> maybe "delamination" ?
    – Lorel C.
    Commented Oct 17, 2018 at 23:22

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