Canning Jars Not Sealing: Maybe it isn’t you

That blessed moment at the end of a canner’s long day. You’ve done all of it right. Filled the jars with good food. You allowed the recommended amount of head space in the jars. Jar rings finger tight. You got your canning racks in place. Loaded the the jars carefully so they weren’t bumping each other.  Right amount of water. Brought the canner up to temperature, timed it to the minute, plus a little more time. You let the pressure come down slowly after you shut down the heat. The lid comes off.

Ah, that whiff of hot sockeye salmon. You pick the jars straight up and out one by one. The lids begin to pop as they suck down tight against the jar. Pop!   Pop!  Pop!  go the jars. That’s the moment. 14 beautiful jars of high quality protein that are now shelf stable and will last for years. But wait…. one of them didn’t seal. Dang. Oh, Oh. another one didn’t seal. What’s up with this?

Everyone who does a lot of canning has the occasional jar that doesn’t seal. It happens. The internet will tell you that when jars don’t seal it’s usually because of something you did, or didn’t, do.  These are the common culprits:

1) leaving too little head space in the jars (in the canner food boils up and gets between the top of the jar and the lid)
2) not wiping the rim of the jar-after you fill it-before you put the lid on (food on the rim can cause a seal failure)
3) not tightening the rings enough.
4) tipping the jars when you take them out of the canner (before they seal)
5) Greasy meats like kielbasa can boil up (siphon) between the rim and lid.
6) A nick in the jar rim you didn’t see. (It’s good to run your finger around each rim just to be sure).

If it’s none of these things, maybe it’s this:


During the pandemic, in 2021/22, people bought up all the canning jars and lids, the ensuing shortage flooded the market with substandard lids.

I had a jar not seal last summer.  As I said, sometimes things happen. But then in the next batch, same thing. Again with the batch after that. That’s way more than usual for me. Trying to figure out what was up, I ruled out the usual suspects. A close inspection of newly opened flat of jars with lids showed the lids had a barely noticeable break on the metal at the edge. I only found it by running my finger around the edge.

I sent a couple photos to a friend who is a power canner. She said due to the shortage of lids the market was flooded with bad lids. She suspected even the big name brands were sourcing bad lids from sketchy producers. Still, she recommended sticking with the big brands (like Ball and Kerr) because canners she’s worked with have tried knock-off brands and ended up with seal failure rates of up to 50%.  Her thought was this might last for a couple years until supplies are back to normal.

Until that happens, if you come across this, and there are no other lids in town, I’ll pass on that I threw out most of these lids that I’d bought. Just as an experiment, though,  I rolled a few of the split edges on the back of a spoon to smooth them out, and they worked. I don’t recommend it necessarily but just saying…

When jars don’t seal, they go in the refrigerator to eat during the next week, or if you’re on a canning roll, you can put on a different lid and can that jar along with the next batch.