# What makes a pressure cooker explode?



## Jokarva (Jan 17, 2010)

My sister texted me a picture yesterday, she had a pressure cooker (not canner) on her stove - and it just exploded suddenly! Left a big crater in her ceramic cooktop and collards all over her kitchen.

I don't know a lot of details...but she said it hadn't cooked dry, wasn't very heavy, and all the gauges and valves were (as far as she knew) in good order.

I've never used one, they make me very nervous (and rightfully so apparently!)...so what causes a pressure cooker to explode like that?


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## Peggy (Feb 14, 2010)

did she let the pressure gauge get too high?


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## Tracy Rimmer (May 9, 2002)

Many people are under the mistaken impression that they can cool down their pressure cooker "quicker" by taking it off the heat and putting it under cold running water. This can cause them to crack. It's just possible that, if this has been done to this pressure cooker, it had a crack that finally gave way.

Other than that, the only thing I can think of is that she let it go too long, on too high of heat, or the rubber exhaust thingy was clogged.


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## Jokarva (Jan 17, 2010)

I don't know, I do know she said that no one was in the kitchen when it blew.

So, do you have to watch a pressure cooker the whole time it's used - don't they have a valve that lets off steam? Just curious...after this I'm pretty definitely never going to own or use one. Killer appliances - scary!


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## tinknal (May 21, 2004)

Well, pressure.

My guess is clogged vent.


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## tinknal (May 21, 2004)

I'm wondering why one would pressure cook collards.


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## fordy (Sep 13, 2003)

Jokarva said:


> My sister texted me a picture yesterday, she had a pressure cooker (not canner) on her stove - and it just exploded suddenly! Left a big crater in her ceramic cooktop and collards all over her kitchen.
> 
> I don't know a lot of details...but she said it hadn't cooked dry, wasn't very heavy, and all the gauges and valves were (as far as she knew) in good order.
> 
> I've never used one, they make me very nervous (and rightfully so apparently!)...so what causes a pressure cooker to explode like that?


...........For the very same reason that boilers on steam engines were known too explode and kill lotsa folks close by ! my mothers pressure cooker has the little thingmajigger on top that allows some pressure to escape to prevent an explosion . , fordy


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## Paquebot (May 10, 2002)

Not all pressure cookers have a dial gauge. Most have only a weighted gauge. If a piece of food blocks the orifice, pressure will continue to build up until it blows up. That can happen if the cooker is filled too full with a food which is fluffy or may expand when cooked. Collards cook down so the cooker may have been overfilled from the beginning. 

Martin


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## Harry Chickpea (Dec 19, 2008)

Flaws in materials do happen. Did she say which brand and model?

Pressure cookers have various methods of handling the pressure. The older ones like we have have a jiggle top, which releases pressure when it gets to a certain point. Above that, there is a rubber safety grommet that is supposed to blow out if the jiggle top fails. If the safety grommet becomes hard, I can see it failing to blow.

I can definitely understand cooking collards in a pressure cooker. Otherwise, they can take hours to become tender.


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## Paquebot (May 10, 2002)

Harry Chickpea said:


> I can definitely understand cooking collards in a pressure cooker. Otherwise, they can take hours to become tender.


And how many times have you started a pot of greens which was so full that you had to push them down to put the lid on? I have done that many times. No problem with conventional cooking but potential big problem with pressure cooking.

Martin


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## clovis (May 13, 2002)

My cousin had a pressure cooker explode many years ago. He was just 14 years old, and was cooking beans in it when it blew.

He luckily missed the lid blowing off, but scalding hot beans covered his face. A scary event , to say the least.


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## Paquebot (May 10, 2002)

Beans are the second of the two potential types to cause trouble. They may expand and plug the orifice with the same results as fluffy greens. Always read instructions as to how full the cooker may be for certain foods. 

Martin


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## Jalopy (Feb 23, 2008)

When we got our ceramic cook top we were told not to either use a pressure cooker or iron cookware on it because it concentrates the heat in one spot for too long a period. So which happened first the failure of the cooktop or the pressure cooker. If the cooktop failed it wouldn't be a big noise but it could have slid the canner at an angle and the contents then blocked the vent and caused the build up of pressure. Since no one was there who knows for sure? Just an alternative theory.


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## patty12 (Jan 25, 2011)

clogged vent. the pressure kept building and could not escape and then something has to go. That happen to my husband once. he had beans on the ceiling.


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## wwubben (Oct 13, 2004)

We never leave a pressure cooker or pressure canner unattended in our house.There are several things that can cause them to blow up.


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## Alice In TX/MO (May 10, 2002)

Pressure cooking collard greens is strange to me, too.

Only two causes as mentioned above. 1) clogged vent 2) flawed metal on the pot body

She's lucky no one was in the room, but if she had been watching, she *might* have realized something was hinky.


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## Harry Chickpea (Dec 19, 2008)

Paquebot said:


> And how many times have you started a pot of greens which was so full that you had to push them down to put the lid on? I have done that many times. No problem with conventional cooking but potential big problem with pressure cooking.
> 
> Martin


Agree. Generally we use greens that we have blanched and frozen, so the worst of that is already out of the way when we put them in a pot.

This thread makes me wonder if a tinsmith could have a market making jackets like large open ended pipes that would sit on the stove OUTSIDE of the burners and act as shields.


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## Tracy Rimmer (May 9, 2002)

There is no reason to be scared of pressure cookers or canners. So long as they're properly used, and not left alone (big mistake), they're perfectly safe.

They need to be monitored, they need to be used according to the manufacturer's directions, and they occasionally need to have their pressure gauges inspected. A properly set up pressure cooker/canner ought to start exhausting steam within 7-10 minutes, even if just a wisp. If you leave it on for twenty minutes and nothing appears to be escaping, you might want to see if there is something wrong.

It takes a LONG time for them to build up enough pressure to explode, if they don't have some sort of flaw or weakness in the metal.


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## bugstabber (May 12, 2002)

As teens, my sisters and I learned that we had to turn the heat down when the pressure cooker weight started to jiggle. That was the cause of the the little pressure release plug blowing out. Now, that causes some excitement! I remember my sister ran over and held a frying pan over the spewing geyser of liquid and steam to keep some of it from the ceiling. 

Did it have a pressure release plug? I'm glad everyone was okay!


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## mrs whodunit (Feb 3, 2012)

Tracy Rimmer said:


> Many people are under the mistaken impression that they can cool down their pressure cooker "quicker" by taking it off the heat and putting it under cold running water. This can cause them to crack. It's just possible that, if this has been done to this pressure cooker, it had a crack that finally gave way.
> 
> Other than that, the only thing I can think of is that she let it go too long, on too high of heat, or the rubber exhaust thingy was clogged.



The instructions for our old and new pressure cookers says its fine to cool with water.


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## SquashNut (Sep 25, 2005)

It must have gotten plugged up.


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## Karen (Apr 17, 2002)

Since a pressure cooker is 'locked down', the only way it can explode is if the pressure gets too high. However, by federal law, any pressure cookers and canners made after 1995, must have at least 2-3 self-releasing pressure valves to keep them from exploding. 

If the pressure gets too high, one or more of those valves (tiny gaskets actually) will either pop themselves off or blow out (depending on the type), creating an automatic steam/pressure release like a vent so the whole thing no longer can blow up. You only actually need 1 pressure release, but the reason for 2 or more is just an extra precaution. If one fails, there's 1-2 backups.


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## oldmania (Jan 25, 2007)

Most newer pressure cookers have an over pressure plug that will blow, preventing the kettle from exploding. Mine also has a screen on the under side of the vent pipe that prevents the vent pipe from getting food in it. I cook 2 pounds of pinto beans in my pressure cooker at least twice a week. I set a timer, but otherwise do not "watch" my pressure cooker. Love my pressure cooker.


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## watcher (Sep 4, 2006)

I'd put my money on a structural flaw if it actually "exploded". I have never seen a home pressure cooker/canner w/o a safety plug. Even if the rubber in that plug was 40 years old and hard as a rock it would blow out LONG before you could get enough pressure to rupture the containment vessel.

In all my years I've seen one cooker and one canner have a failure. Both times it was the pressure release plug which failed, which is what is supposed to happen. In both cases steam and chunks of food were blown out of the hole with great force. It did look like something had exploded but when you got closer you could see the cooker/canner was intact. 

Like most things they can be dangerous if abused or used incorrectly. The main thing is to check that little safety plug. If it looks the least bit damaged or "wrong" in any way replace it before using the canner/cooker again.


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## Seagrape (Aug 4, 2008)

tinknal said:


> Well, pressure.
> 
> My guess is clogged vent.


That was my thought, too. Pressure got too high--most likely a clogged vent.


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## Evons hubby (Oct 3, 2005)

Jokarva said:


> I don't know, I do know she said that no one was in the kitchen when it blew.
> 
> So, do you have to watch a pressure cooker the whole time it's used - don't they have a valve that lets off steam? Just curious...after this I'm pretty definitely never going to own or use one. Killer appliances - scary!


Too much pressure..... thats the only thing I know of that will cause one to explode. Ok, maybe someone might be stupid enough to try and dry out some gunpowder... but thats really not the norm.


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## SteveO (Apr 14, 2009)

So what actually blew??? did the top come off or the sides split?
A picture of the damaged vessel would be great to see.
If the vessel was flawed I would think it would spring a leak on the side but at 15lbs pressure would not explode. I'm guessing the blow off had dried whatever in it and was pluged solid from the last use. With no place for the pressure to go i wouold think the weakest point would be the lid
Pictures please


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## jwal10 (Jun 5, 2010)

Never saw one explode. Seen plugs pop, makes a real mess. Seen the lid blow off because it was not on right and seen a bottom rupture on one. Also seen it blow the jiggler right off. My guess would be it got dry and heat was too hot. Don't think you should use a pressure cooker on a glass top range. I use a pressure cooker 2-3 times a week, never a problem....James


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## Jokarva (Jan 17, 2010)

SteveO said:


> A picture of the damaged vessel would be great to see.
> 
> Pictures please


This was my sister's, so no pics except the one she texted me of the hole in the stove top itself. 

I do have a little more info though - the lid blew off and knocked a hole in the ceiling, so it didn't explode shrapnel wise. My DS and BIL both thought the other was watching it...so no one was. It didn't go dry, there was juice from the greens (turnip, not collards it turns out) all over the kitchen. The cooker was an old one they'd used for years (that he bought at a garage sale for next to nothing)...but I don't know if they've decided the vent was damaged or plugged or what.

The kitchen is cleaned and insurance is paying for a new stove top. No word if they're getting another pressure cooker though...but I think they will. They used this last one all the time.


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## Alice In TX/MO (May 10, 2002)

I still don't understand pressure cooking greens. Might as well put them in the blender and make green mush. :nanner:


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## LadyJane (Nov 23, 2005)

mrs whodunit said:


> The instructions for our old and new pressure cookers says its fine to cool with water.


We have a stainless steel pressure "cooker" and ours does too.


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## Paquebot (May 10, 2002)

Alice In TX/MO said:


> I still don't understand pressure cooking greens. Might as well put them in the blender and make green mush. :nanner:


Instructions for canning any greens is in a pressure canner at 10 pounds of pressure, 70 minutes for pints, and 90 minutes for quarts. They do not become mush.

Martin


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## Ann-NWIowa (Sep 28, 2002)

I would guess she did not have the lid locked on right. If the lid had been on correctly the safety plug should have blown rather than the top blowing off. 

I had the vent clog with beets in the pressure pan and the kitchen ended up looking like a blood bath because the pressure went down all at once spewing liquid from the vent. I quickly turned off the heat and got the heck away. I guess it didn't clog so much as force a food particle up thru the vent which make it spew.

I would NEVER leave a pressure pan or canner unattended while under pressure.


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## Alice In TX/MO (May 10, 2002)

She wasn't canning. The original post specifically says not canning.


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## Paquebot (May 10, 2002)

Alice In TX/MO said:


> She wasn't canning. The original post specifically says not canning.


Stop and use your head. The contents would be under the same amount of pressure regardless of the operation with the same cooked results. 10# in a jar or 10# in the pot, no difference. 

Martin


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## Paquebot (May 10, 2002)

Here's directions which cook collards in 5 minutes in a pressure cooker rather than 30 minutes to an hour in an open pot.

www.grouprecipes.com/19343/easiest-collard-greens.html

Martin


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