There is no acknowledged change in the glass formula from Jarden-Ball as long as you stick with their products and no increase in complaints that I am aware of. Some feel the jars have gotten thinner and when compared to a 20-30 year old jar that is pretty obvious. But the market of late has also been flooded with off-brand and copy-cat jars and lids that many have complained about - Mainstay, Empire, etc. - that are China-made.

But that said, and as one who recently posted here about my own thermal shock issue i have sympathy for you. But it is preventable regardless of the jars used. I know mine happened because even though I was doing things just as I always have for decades, I was rushing to play catch-up from a distraction and I hadn't bothered to check my water temp in the canner before inserting the jars. Clearly in hindsight it had been heating up longer than usual and it was hotter than normal and jar had cooled more than usual on the counter. So while I'd love to blame the jars, I really can't.

When doing cold pack knowing the temp of the water is even more important of course. In fact I have gotten into the habit of just filling the canner with warm tap water and no heat turned on until after all the cold pack jars are loaded. I'd say "hot" tap water but that all depends on what your water heater is set at. Mine is set at 180 so that alone would be too hot for cold pack jars.

Dave

Over the years I have had bad luck with golden harvest pint jars. Lost 3 more this year.

Its weird but my so called junk canning jars never break.

For the record mainstay lids are now made by Jarden and look like golden harvest lids and 80 cents less than ball lids for the 70 MM size.

Clearly I'm going to have to adjust my methods. Perhaps going to hot packing peaches-- easier to get full jars that way anyway. I'd hate to add 15-20 minutes of heat-up time to the processing time. Tomatoes won't be so sensitive to overcooking, so I can start with temperate water and heat more slowly.

I wonder of they've shortcut the annealing process in manufacture? That would be an easy way to save cost for them. That might explain this behavior. I don't have access to an appropriate oven any more or I'd think about trying an experiment.

At this point my recycled spaghetti sauce jars are outperforming the (presumably) authentic Ball jars. I hadn't considered counterfeits. That's a disturbing possibility.

rwiegand, I also have numerous "recycled" jars from spaghetti sauce and mayonnaise, and they have proven to be as reliable as my brand name jars, at least when used for water bath canning.

I just used a dozen brand new wide mouth quarts for canning mature pink half runner beans. I use the same time as required for pinto beans, 50 minutes, and they all came out of the canner unscathed. However, I did lose one old Ball pint to thermal shock while canning sweet pickles, so they seem to me to be pretty consistent with my past experience, but they do seem much lighter.

Annie