Canning some strawberry jam today, went to check on most recent batch and there was a jar floating at the top and the water was red… took the floater out and this is what i found 😳. This is a first for me – any way of preventing this in the future?
by Inside-Object4916
6 Comments
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Most likely this is thermal shock. The best way of preventing it is to make sure that the jars never undergo a sudden/ rapid temperature change. So hot jam into hot jars into hot water then onto a towel or other insulating material (cork mats are also fine, just not metal, stone, etc. that will cool the jar too fast) to cool slowly.
I had this happen to me for many reasons.
I had a bad batch of jars that made it past quality assurance when they shouldn’t have. New, out of the box. Every last one had the bottom bust out from the two boxes in raw packing tuna.
I had jars that were old. Antiques, but the family had been using them since the day they were new in 1960. So raw pack, canning tomatoes (unsafe practice, do not do!) had a couple jars blow out. That was thermocycling catching up and thermal shock! Had tuna jars bust from thermocycling too.
In the early days, had the water bath canner rolling boiling hard by the time I came out with the hot packed peaches. Thermoshock got me crying again and learned from that.
From time to time I lose a jar here and there. Generally from some micro fracture and thermocycling because I do have a fair number of old jars. Other times it’s from haste, in not getting all the bubbles out, lid too tight (have a jar wrench that eliminated that problem, but sometimes I forget to bring it) poor heat management, or a combination of everything and some mistake I made. It happens to the best of us too.
For me it was pickles. It happened the most with jars I made pickle slices and I think it was because I didn’t do enough to remove bubbles that may have been trapped underneath the horizontally stacked slices.
I am curious what size jar are we looking at? It always is a question because of the processing involved and general filling of jars can always be a factor as well.
Make sure the bottles have zero nicks in them and make sure the bottles don’t bump together when lowering into the water bath. I feel your pain OP