Free Canning Jars are Not Always a Good Deal

canning jars

Recently we were given a large number of free canning jars in various sizes about 10 cases.  My wife was happy to get them and thought that it was a great deal.  Unfortunately, there was a catch.  When you started using the jars, they worked fine when you used them in water bath canning.  When you tried to use them for pressure, canning the problem started.

The bottoms were failing and falling out of the jars.  This was only happening to the ones we got for free.  The break was similar to the ones you get from thermal shock with the break running around the base of the jar.  Because of the way in which she cans we know it wasn’t her problem.  She is an experienced canner and all her other jars were coming out fine.

The one thing that immediately popped into our minds was the way the canning jars had been stored prior to our getting them.  They had been stored outside in a lean-to in cardboard boxes and exposed to the heat and cold for at least 5 or 6 years.  The temperatures ranged from below freezing to over a 100° F.  I think that the constant changes in temperature weakened the glass.

They work fine for vacuum sealing and water bath canning, but not pressure canning.  So we will only be using the rest of the jars for limited purposes.  My wife intends to make a black X on the bottom so that she can identify them.

Up until now, we have never worried about the temperature in which we stored canning jars.  But in the future, we will make sure they are stored under the best possible condition inside with moderate temperatures.



7 thoughts on “Free Canning Jars are Not Always a Good Deal”

  1. Perhaps there was half an inch of water in them and it froze? The expansion may have fractured the glass?

  2. This post comes at a perfect time I was thinking about purchasing a large quantity of canning jars. I was thinking of storing them in my attic, now I need to think twice about that.

  3. This experience reinforces our family folklore. My grandmother always insisted that only new Ball jars be used for pressure canning. Used jars and others gleaned from grocery purchases, etc. would be used only for cold pack, water bath and vacuum sealing. She was always adamant on this and nobody dared argue, lest you get the switch! She had an Irish temper! Gramma always put a paint park on the bottom of the jar each time it was used, and once it was used three times, the jars were scrapped. The old bitty knew!

  4. Also be wary of free containers that look like canning jars but may not be as strong as real ones. For example, my family loves Classico spaghetti sauce so we end up with lots of empty jars that just beg to be re-used, but the company web site specifically says not to use them for canning: Of course they work great for dry goods (beans, grains, dehydrated fruit) and some of them even fit standard canning lids and a FoodSaver vacuum sealer, but I wouldn’t put them in a pressure canner.

  5. I have not been able to find the answer to my cheese preservation problem. I saw a video some months back about dipping cheese blocks in wax to preserve it for months maybe years , I can not remember . I bought a 1lbs block of triple filtered bees wax , and a block of paraffin wax , does any one know which one should I use, does it even matter? with time growing short I would really appreciate some advice.

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