# Jars Breaking In Pressure Canner



## akhomesteader (Jan 5, 2006)

A few years ago I bought an All American 921 pressure canner. Almost every time I can something, one jar in the top rack breaks (not always in the same place). Any ideas on what I might be doing wrong, or what I need to change. I've been canning food for 20 years, and until I got this wonderful canner, I hadn't broken more than 3 or 4 jars. Now it happens all the time. Doesn't seem to matter if I'm using wide mouth or regular jars. 

I thought I might try leaving one jar out to see if maybe they were too close. One still broke. I let the steam escape for the right time, and keep the pressure right. The weight jiggles at least once a minute, like the instructions say, although the gauge says 12 pounds of pressure. I cook on a woodburning stove, and sometimes the pressure gets slightly higher, so I have to move the canner from time to time. But I've always had to do this, even with my old canner and never had jars break. Maybe I should let steam escape a few extra minutes???

Thanks,

Jenny


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## oregon woodsmok (Dec 19, 2010)

Are you using those jars from China? Lots of complaints about those breaking.


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## Pam in KY (Jul 26, 2011)

I've heard a lot of complaints about Wal-Mart's Mainstay brand breaking too.


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## akhomesteader (Jan 5, 2006)

No, these are Ball and Kerr. Some are very old, made in USA; some are newer, made in Mexico.


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## Macybaby (Jun 16, 2006)

How are they breaking - bottom popping off or something else. And is it always in the top rack, meaning you don't have this problem with quarts, only when you double stack pints.

It's rather strange, and should not have anything to do with the canner, but if it is only when you doulbe stack that makes it harder to figure out.

The only time I had a lot of breakage - I attributed it to someone must have dropped the box of jars and stressed the bottoms. They would crack in sort of a horizontal line about 1/2" up from the bottom. Basically, the bottoms fell out. 

Another thought, but this would not be the case if they are only the top layer, would be if you are using something metal to remove air bubbles and started scoring the jars. Then they would break differently too. 

And maybe your upper jars are cooling down too much before getting put into the canner, and then they are dealing with heat stress. 

Did you have a canner big enough to double stack before?

I've got four pressure canners, including the 921. This will be interesting to see if you can get to the bottom of it.


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## MichaelK! (Oct 22, 2010)

If they are breaking at the base of the jar I would say that heat conduction through the metal tray they are sitting on is too fast. You could try putting a circular pan like a cake pan on top of the lower section, then adding a little water to the pan so the top jars are sitting in water, not bare metal.

In autoclaves glass breakage was common till I made sure glass jars were sitting in water.


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## akhomesteader (Jan 5, 2006)

Thanks for all the replies. I think I was heating the canner too fast. I slowed it down a bit for my last few canner loads, and not a single broken jar. It was only on the top rack, and only one jar broke each time. The bottom was falling out. I haven't tried canning quarts in this canner yet. My last canner only held one layer.

Thanks again,

Jenny


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