1) I am canning over a campfire. The heat is difficult to regulate this way, and extreme heat could contribute.
2) The jars that have been breaking are old and have been used many times over the years.
3) only the older Kerr jars are breaking. My Mason jars, which are older, have faired just fine. None of my Ball jars and no newer Kerr jars have suffered.
4) No cracks, chips, or deep scratches are obvious.
I used only Mason and Ball jars the past two nights, and only the Kerr pint jars, and I am happy to say that there was zero failures.
Your guess is as good as mine. I think the combination of age, and extreme heat are the main culprits. And possibly just a bad batch of glass.
I found when I can over fire or gas stove to placea folded kitchen towel in the bottom of canner underneath jar rack stops jars from cracking and breaking' don't have this problem on electric stove but hate canning on it.
Good idea Peggy! I will try it out and see what happens.
I have researched jar breakage and have very little of it now. If the jar is broken vertically it is pressure but if the break is around the jar horizontally it is a temperature difference. Your photo looks more like a vertical break as it blew a chunk out of the side so I would say that possibly the ring was too tight with a drastic temperature rise maybe. I have used jars over 100 years old without problems as well as non canning jars such as what mayonnaise used to come in and have had more name brands break than plain jars. All jars are tempered, any difference is that one has someone's name on it. I will say that quarts and especially wide mouth ones seem to have more issues than pints. They must use thin glass in quarts and also ironically pressing their name in the side along with decoration seems to make them less concentric and more unstable than say a mayonnaise jar which is just smooth glass.
I always use a towel under my jars in the pot, my moms taught me that. try it, I have never had a breakage....beans look great@ I cannot wait for mine!
Try putting a folded towel on the bottom of the pot you are canning in, this may help it is something my Grandmother did when canning on her wood stove out in the summer kitchen and she claimed it kept the jars from "cracking" on her. Could help.
I equate her wood stove canning to your method outside, I can on a bar-b-q that you can wood fire and so far so good, and some of my jars are about 50 years old have had them since I was first married. Hope it helps.
Age does have something to do with breakage. However, that does not mean a jar is too old. Anytime a jar is dinged against another or dropped (and we have all had this happen) a tiny chink in the glass can weaken the glass. The chink may be miniscule and not visible to even close scrutiny, but it will weaken the jar. When that weakened jar is used for canning, there is the likelihood it will break. So, an older jar has more miles on it and more possibility of having suffered a bit of inadvertent abuse.
I cannot say about the wood heat or any of that. But, the high heat may be finding all the dinged jars. Just a thought based on no evidence. lol
It is my firmly held belief that Ball jars are the best. I don't use anything else for canning. But, my belief may be false, and I won't debate anyone on that. Well, I may use a Kerr that comes to me, but never buy Kerr, although that is still a good jar and made by Ball, I believe.
When I can without a rack, using a smaller pot that is not for canning, I put a towel on the bottom of the pot and put the jars on the folded towel. So, not even using a rack on the bottom, the towel prevents the jars from touching the bottom and cracking.
A different glass is used for canning jars to make them stronger than a mayo jar. Plus, the glass in a canning jar and the screw part is thicker. The name is not stamped on a jar; glass is poured into a mold.
The rim on a canning jar is thicker to make a wider place to connect to the rubber area on the lid in order for it to have a better seal.
The waste you are experiencing is just killing me.
Hopefully, you can get this worked out. But, everyone should be careful about clinking jars against each other, the floor, or anything else. Even I should be more careful.
Well, I have had several jars break in the exact way the one in your pic did, and for me it was always with older "new" jars, meaning jars that were made in the last 10 years, but used many times. Sometimes they broke the minute they entered the canner, even though they were already packed with hot goods and warm enough that temperature difference was not the issue! The old, old jars (20+ years old) last forever and never break, and brand new ones never break either. So I think the newer glass is just not made like it used to be, and develops a sort of structural fatigue after several canning seasons. Nowadays, I use my jars for a maximum of three years, then repurpose into drinking glasses, coffee mugs, or water bottles.There is nothing more frustrating than losing a quart of something inside the canner because the stupid jar broke, so for me its worth the cost.
All mason jars are made by one company, it is a monopoly that is why lids and jars cost so much. The only jars not made by the same company are the ones imported from China.
Do you have a tray that fits in your pot to sit your canning jars on?
If not, a small towel will work inside the pot.
Yes, I do have a rack.
Even if they are all made by the same company, it is the Kerr jars I am having problems with. None of the others have broken.
In 40 years of canning I've had lots of jars break, almost always the whole bottom drops out like your photo. And for some reason it has almost always been beans that were lost. Perhaps it's something to do with the beans?? I've never water bath canned them, always pressure cooker, and I've found over the years that venting longer than the recommended time has helped.
I agree with the towel on the bottom of the canner. Best of luck with the rest of the canning.
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