How often do you lose a pressure canned jar?

Cathy sent me down to the cellar for a half-pint of raspberry jam yesterday. I also found this nasty jar of moldy salsa. There was enough of a seal that it popped when I opened it, but it also came open much too easily…with casual pressure from my thumb.

Anyway, this doesn’t normally happen to me, but we’ve been canning for just five years and have probably only put up 200 jars — maybe a bit fewer than that.

What’s your experience?

I have never seen that happen.

Were all the other jars of salsa okay?

Anne Miller wrote:Were all the other jars of salsa okay?

Yes! That's the only one. When I popped the lid off, I looked to see if we had sloppily left a bit of food on the rim that prevented a good seal, but there was nothing obvious (after 3.5 years...).

I find it gets more common after the jars pass the 2 year mark.  At any given point in time, we have maybe 500 filled jars in the basement.  Just sitting here guessing, I would estimate that those jars less than 2 years old the failure rate is near zero.  By 5 years it is close to 10%.  By any case, I always check the lid before I take the jar off the shelf.  I use a variety of brands of lids. And, though not often, I have reused lids.

This might also just have been a false seal. Did you wash and pull on the lid after you pressure canned it?
That said, sometimes things just happen. My son made and canned pear pie filling, but must have been rushed and skipped a step or two, because I have tossed three jars so far, that has grown mold.
Also, I clean my food storage pantry once a year, and that includes any jars, that has gotten dirty. While there I also check all the seals on the jars. I usually do this in January or February when there are the least amount of jars in the pantry. That way I know what I have left, that they are all still good and clean, and what I am running low on.
Then I organize my empty jars, check for dirt and chipped jars, so they are ready to be filled again. This saves time and effort later.

Agreed - could have been a faulty lid, too. It's pretty rare, in my experience, but not unheard if. It's exactly why the companies that make both the canner & jars tell you to check them, periodically.

I actually had half a batch of Jam go bad like this recently. The jars were sealed but the lids popped off to easily and were moldy. Our issue was storage location. Our house gets cold in the winter at night, like regularly in the 40s. Then jumps back up to the 70s during the day. And I had stored them above the stove compounding the temperature differences and caused the failed seals. At least I'm pretty sure this is what cause the problem. The other half of that batch was in the basement and we had no failed seals on them. But the temps are way more stable down there. But otherwise if I'm using all new lids Iv never had a issue with them sealing and then going bad. We pressure can our beans and stock once a month and that's about 80 jars a month. Sometimes jars don't seal right out of the canner but that happens to everyone and are pretty easy to catch.