# Lids blew off jars



## farmhousecrafts (Jul 24, 2015)

I pressure canned beef broth last night. The pressure was correct the entire time and the length of time was correct. When finished, I Waite until the pressure went down.

When I took two jars out of the canner and sat them on cloth towels, the lids blew off both of them, burning my hands. It could have been worse. I've never, ever had this happen before, and I've been canning for 40 years!

I tighten the rings, but not too tight. In the future I plan on waiting a very long time before taking the lid off and removing the jars.

But I'm just wondering if anyone else has had this happen?


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## Declan (Jan 18, 2015)

I've heard of it happening, but I don't think it is common. My guess is if you did everything by the book, the lids had defective seals on them. That you were burned, however, makes me think it was something else.


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## farmhousecrafts (Jul 24, 2015)

Later I thought maybe the lids jiggled loose. But I checked the jars left in the canner and they were not loose enough to blow off.

Maybe just moving the canner and moving the jars before they were cooled off caused the built-up pressure to do it. I don't know.

But I DO know I'm letting them completely cool off before ever moving them again!


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## po boy (Jul 12, 2010)

farmhousecrafts said:


> I pressure canned beef broth last night. The pressure was correct the entire time and the length of time was correct. When finished, I Waite until the pressure went down.
> 
> When I took two jars out of the canner and sat them on cloth towels,* the lids blew off both of them,* burning my hands. It could have been worse. I've never, ever had this happen before, and I've been canning for 40 years!
> 
> ...


Were the rings still on the jars?

They say finger tight but I tighten mine very tight.


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## DW (May 10, 2002)

OMG...I've canned for yrs, too. I read somewhere to leave the rings on 24 hrs before you remove them and I usually do this.


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## NEfarmgirl (Jan 27, 2009)

I had a jar of beef stew blow on me after removing it from the canner and I assumed it was from a very sudden temperature change. It was a cooler fall evening and the house was opened up still because I had been canning and baking so it got really warm in the kitchen. I pulled the first jar out and sat it on the counter (towel under it) and nothing happened. I pulled the second one out and set it down to have a volcano of beef stew blow out and hit the ceiling. There was a piece of thin metal cover (for covering ceiling light fixture boxes when you don't need them anymore) under the towel and it was very cold to the touch. I assume the sudden temperature change cause the liquid inside to boil extremely hard causing the lid to fail. None of the other jars did that. I'm sorry you were burned and hope you heal quickly!


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## Cajun Arkie (Jun 11, 2012)

I have never had the lids to blow off but I have had the broth to spew out of the jar when I took the canner lid off. This started immediately after I took the pressure canner lid off and continued for quite a few seconds. I let the jars sit there for a long time before I took them out of the canner. I decided later that perhaps I filled them to full even though I was careful about the head space. I don't know if this makes a difference but they were all wide mouth jars. I also have had beef after I took the pressure canner lid off to seal and unseal and seal and unseal for maybe 5 or 6 times before finally sealing. Now I just take off the jiggler and loosen the lid and let it sit awhile before I try to take them out. I have also been canning for years and have never had this happen until recently.


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## vicker (Jul 11, 2003)

The only thing that would make the lid blow off is if the contents began to boil. The pressure of the canner raises the boiling temperature. If you release the pressure on the canner before the contents of your food containers is below 112f or even lower, depending on your elevation, the contents are going to boil. If the temp is over 112f it is supper heated and will pretty much convert to steam instantly.


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## farmhousecrafts (Jul 24, 2015)

po boy said:


> Were the rings still on the jars?
> 
> They say finger tight but I tighten mine very tight.



Yes, the rings were still on the jars. It was when I sat them on the towel on the counter that the rings and lids blew off.

I have since canned 5 jars of chicken broth. I did not remove the lid of the pressure canner for 4 hours. I didn't even move the canner at all, just left it on the stovetop. I wanted to make sure it was all cooled off.

After 4 hours, when I opened the canner, two of the lids and rings from the jars had blown off. Good thing I waited and that they blew up inside the canner.


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## farmhousecrafts (Jul 24, 2015)

DW said:


> OMG...I've canned for yrs, too. I read somewhere to leave the rings on 24 hrs before you remove them and I usually do this.



I never remove the rings at all.


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## farmhousecrafts (Jul 24, 2015)

Cajun Arkie said:


> I have never had the lids to blow off but I have had the broth to spew out of the jar when I took the canner lid off. This started immediately after I took the pressure canner lid off and continued for quite a few seconds. I let the jars sit there for a long time before I took them out of the canner. I decided later that perhaps I filled them to full even though I was careful about the head space. I don't know if this makes a difference but they were all wide mouth jars. I also have had beef after I took the pressure canner lid off to seal and unseal and seal and unseal for maybe 5 or 6 times before finally sealing. Now I just take off the jiggler and loosen the lid and let it sit awhile before I try to take them out. I have also been canning for years and have never had this happen until recently.



That's what I am thinking, maybe I filled them too full and I also used wide-mouth jars. It said to leave 1" head space, which I did. I need to try again and leave more head space and see if this makes a difference.

I'm bound and determined to figure this out!!


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## farmhousecrafts (Jul 24, 2015)

vicker said:


> The only thing that would make the lid blow off is if the contents began to boil. The pressure of the canner raises the boiling temperature. If you release the pressure on the canner before the contents of your food containers is below 112f or even lower, depending on your elevation, the contents are going to boil. If the temp is over 112f it is supper heated and will pretty much convert to steam instantly.



I have since canned 5 jars of chicken broth. I did not remove the lid of the pressure canner for 4 hours. I didn't even move the canner at all, just left it on the stovetop. I wanted to make sure it was all cooled off. 

After 4 hours, when I opened the canner, two of the lids and rings from the jars had blown off. Good thing I waited and that they blew up inside the canner.

I would think after 4 hours the temp would be below 112.


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## Cajun Arkie (Jun 11, 2012)

farmhousecrafts said:


> That's what I am thinking, maybe I filled them too full and I also used wide-mouth jars. It said to leave 1" head space, which I did. I need to try again and leave more head space and see if this makes a difference.
> 
> I'm bound and determined to figure this out!!


I forgot about this until just now but I also canned some broth in regular mouth pints. Processed them for 75 minutes - they were boiling when I undid the canner lid but did not spew like the wide mouth ones. I have 30 pounds of chicken in the freezer waiting on me to have time to can it and make broth. I will try regular mouth quarts and see what happens. Since I used proper canning methods and headspace and only the jars were different I am wondering if this could be a factor. Am not planning on doing this now until after Christmas but will let you know.


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## haypoint (Oct 4, 2006)

Since you need vacuum in these jars, I'd be careful not to tighten the rings too much. The pressure in the jars when boiling needs to escape. Then the vacuum seals the jar.


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## StL.Ed (Mar 6, 2011)

farmhousecrafts said:


> I have since canned 5 jars of chicken broth. I did not remove the lid of the pressure canner for 4 hours. I didn't even move the canner at all, just left it on the stovetop. I wanted to make sure it was all cooled off.
> 
> After 4 hours, when I opened the canner, two of the lids and rings from the jars had blown off. Good thing I waited and that they blew up inside the canner.
> 
> I would think after 4 hours the temp would be below 112.


What brand of jars and bands are you using? 
If the bands are blowing off in the canner, it sounds like there might be a misfit/defect in the manufacturing process.


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## arrocks (Oct 26, 2011)

The most common cause of what you are experiencing is rapid changes in pressure (not temp). The pressure inside the jars is higher than the atmospheric pressure outside the jars. So the problem is in pressure methodology, not the type of jars, headspace, moving the canner, etc.

Assuming you are not making frequent or big heat source adjustments that will affect the internal pressure then if you have a gauge-only canner then it often means there is an issue with your gauge not reading accurately and may show it has returned to zero pressure when it isn't really zero. 

If a weight-only canner then it usually means there is a problem with the steam vent or weight itself. Or the weight is being removed before the pressure inside the canner has returned to zero.

If your canner has both weight and gauge then normally the weight is more accurate but you could still have issues with both.

Either way it is an inconsistent pressure issue.


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## haypoint (Oct 4, 2006)

A pressure caner builds up pressure. The increased pressure keeps the liquids from boiling at 212 F . It takes a higher temperature to boil. This allows the temperature to exceed 212 F, killing bacteria that could survive a lower temperature. The contents of your jars is above 212 F, but not boiling when under pressure. The temperature must drop below 212 F before the pressure drops to zero. There shouldn't be any pressure difference in the jars and couldn't be if the lids weren't cinched down. When the contents drops to below 212 F, the pressure in the caner should be released slowly. Pressure will be escaping from inside the jars, too. Release the pressure too fast and more than air pressure will escape the jars. You'll have a mess. 
While still scalding hot, but under 212 F, firmly tighten the rings onto the jars. As the contents cools, it contracts, pulling the lid on tighter, sealing the jar.
If the temperature stays above 212 F, and the pressure goes out of the canner, the contents will begin to boil, even if the heat is off.


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## Dogwoodfarm (Oct 4, 2011)

Hi, my first post here. I've canned for 30 years and can tell you that for me broth and stock act much different than soups or solids with liquid. When I can broth the liquid seems much more volatile and even causes more and louder pinging of the lids. The last batch I did pinged on and off cycling sometimes 5 times. This has happened more than once with Ball lids and other brands. I don't know if it's because it's all liquid or what but it was scary. I'd be interested to hear if anyone else has the pinging issue with straight liquid.


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## Cajun Arkie (Jun 11, 2012)

Dogwoodfarm said:


> Hi, my first post here. I've canned for 30 years and can tell you that for me broth and stock act much different than soups or solids with liquid. When I can broth the liquid seems much more volatile and even causes more and louder pinging of the lids. The last batch I did pinged on and off cycling sometimes 5 times. This has happened more than once with Ball lids and other brands. I don't know if it's because it's all liquid or what but it was scary. I'd be interested to hear if anyone else has the pinging issue with straight liquid.


I have had this same issue. After reading this thread I am beginning to think it may be the lids. I have been canning for years and never had this happen before. I leave the lid on the pressure canner for a good long while now because I am concerned about them just blowing off altogether as happened here.


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## WendyJH (12 mo ago)

Today, for the first time in over 60 years of pressure canning I had this happen. The ring and the lid blew off inside the canner. The canner had yet to be opened and had not dropped its pressure yet. After the timer went, I turned off the heat and about 15 minutes later there was a loud bang inside the canner and I feared a jar had exploded (has happened) and hoped it didn't take others with it. An hour or so later, when the pressure finally dropped I removed the weight, cracked the lid and let it rest a few and when I finally removed the cover I was surprised to see it was a ring that had blown off, and the lid, spewing 1/2 the contents of the jar. How would the pressure be so drastically affected inside the canner while still under pressure? I have canned outside where the canner cools rapidly as does the pressure and I have pulled jars that are still boiling but never have I had a lid AND ring blow like this did.



arrocks said:


> The most common cause of what you are experiencing is rapid changes in pressure (not temp). The pressure inside the jars is higher than the atmospheric pressure outside the jars. So the problem is in pressure methodology, not the type of jars, headspace, moving the canner, etc.
> 
> Assuming you are not making frequent or big heat source adjustments that will affect the internal pressure then if you have a gauge-only canner then it often means there is an issue with your gauge not reading accurately and may show it has returned to zero pressure when it isn't really zero.
> 
> ...


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## Danaus29 (Sep 12, 2005)

Did you check the threads on the jar to see if they were okay? Did you feel for chips missing from the lip of the jar? Was the ring old and worn or rusted? Did you leave headroom in the jar and remove the air bubbles before sealing with the lid and ring?


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## ladytoysdream (Dec 13, 2008)

Hi Wendy, 
What brand name of your canning jar ? 
Older jar, or new ?
What brand name of the lid ? 
Was the rim of the jar clean of food before you put the lid 
in place to can ? 
Was the collar new or old ? 
One jar maybe just a fluke. If it was the whole canner load 
then it would be a bigger concern.


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## muleskinner2 (Oct 7, 2007)

When you day "blew off" do you mean the ring and lids flew across the room, or that the lid leaked broth?


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## Pony (Jan 6, 2003)

Once the canner normalized pressure, I let it sit for 10 minutes. After I remove the canner lid, I let it sit for another 10 minutes.

So far, so good. <knock wood>


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## Eric Shaw (8 mo ago)

Do you leave the lid finger tight while boiling? Then tighten once the pressure escapes? Asking


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