I have been canning for several years and the only time I broke a jar is when I used a very old one. It was a square looking ball jar.

I am guessing you got some bad jars.

Jay

the only thing I could contribute to this was the contents of the jar cooled too much before I placed them in the boiling water bath.

This raises a couple of questions. First, the goal when hot packing food should be to pack quickly enough so that your product does NOT cool down before it gets placed in the BWB. It is important to maintain the temp level of the product from pot to jar to BWB for food safety reasons.

Second, was the water in your BWB actually boiling or just hot when you placed the jars into it? It isn't supposed to be actually boiling. ;) It should be pre-heated to approximately 180 degrees but placing any jar, even a very hot packed one, directly into 212 degree boiling water can easily result in breakage and injury to yourself.

So if I read your comments correctly, you need to be both packing much more quickly and place each jar as it is capped into the hot (not boiling) water, then fill the next jar, etc. Only after all jars are in the bath do you turn up the heat to bring it up to a boil.

Make sense?

Dave

When I fill jars with the boiling contents, cap,and screw on the bands, I only do enough for a single batch. My canner has already been brought to a boil and then switched off, so the hot jars are just fine. You need to work VERY fast between the filling, capping, and into the bath. Here, rarely do a see a broken jar. If they are older ones and were used several times, they can get weak and crack. I usually see the bottoms break out as opposed to vertical crack.

This is my first year canning and surprisingly, I haven't broken any jars in the BWB (the kitchen sink is another story). I sterilize my jars in the BWB and after 5 - 10 minutes, take the jar out, pour the water out, fill it, screw on the lids and put it right back in the BWB. Seems to be working for me :-)

How did your jars break? If the bottoms fell out that's thermal shock and supports what Dave says about jars and contents being too cool.

If there's a crack up the side that's a stress fracture indicating damage in shipment or handling at some point.

Carol

I agree with Carol, if the bottom falls out, it's thermal shock, too hot water and too cool jars/contents.

I break a jar or two a year, sometimes, and sometimes none at all. I use jars that were my Grandmother's, sometimes 40+ years old, old mayonnaise jars, anything I can get a lid on. Breakage is still minimal and mostly due to jars that got knocked around during storage.

Annie

I must have read this in the Ball Canning Book after breaking several jars last year.

I put the BWB pot on the stove.
Place in the rack.
Add the empty jars.
Fill the jars with water. Add water into the pot far enough up the sides of the jars WITHOUT causing them to float.
Heat the jars while I'm getting the food item done.
When the food is ready I remove one jar at a time.
Empty the hot water into the kettle. Fill and seal the jar and return to the kettle.
I did this with each jar and it was much, much more successful.
I'm sorry if that was too wordy, because it is actually a very easy process.

Cream

I've only been canning for a very short time but I agree that (at least for water bath canning) filling the canner with the clean jars filled with water and filling the canner with enough water to cover the jars and boiling the jars for 10 minutes for sterilize makes it easy. Once the jars have sterilized I usually put the heat under the canner down low to keep the water hot but not boiling. When the product is ready to go in jars, I can do that one at a time and the jars are hot and ready. I just need to bail some of the water out of the canner as I go or it will be too full.

It isn't quite as easy when I'm pressure canning though since I don't necessarily want that much water and I can usually do twice as many pint jars.

To pass on something I just learned recently from the complete book: The initial time the empty jars spend in the bath does not have to be to the boil, and is not to sterilize them - it's to prevent thermal shock. The resultant timed boil (with contents) does the sterilization, no pre-sterilization is necessary (and wastes energy).

The resultant timed boil (with contents) does the sterilization, no pre-sterilization is necessary (and wastes energy).

True - for anything that will be processed for longer than 10 minutes. But to clarify - the rule is that things processed for less than that amount of time need to go into pre-sterilized jars.

Dave

To clarify, boiling jars does not "sterilize". It does kill a lot of bacteria but to be sterile would require a pressure autoclave.
Doesn't really matter, though as food prep is as far from a true sterile procedure as you can get. You would need a sterile room, sterile equipment and surgical sterile clothes/mask and gloves.
We are using more of an aseptic technique, keeping organisms to a minimum.
Thus, the reason for pressure canning requirements on low acid foods. There is no way to fully eliminate bacterial contamination in the kitchen, try as we may.