Sounds like siphoning as a result of a too radical change in temperature. This happens when jars are removed from a canner before the internal pressure/temperature stabilizes or acclimates to the outside temperature. Often you can tell if a jar isn't "ready" to come out of a canner after a long processing time by how much bubbling is going on inside the jar before removing it. If I see the contents of a jar increase in bubbling when I start to lift it out, I put it back in the canner and wait another 5 minutes to try again. Quick question though, did you vent your canner for 10 minutes before opening it? I vent mine for 10 minutes after depressurizing, then open the lid and wait another 10 minutes before removing the jars.

I vented it for five minutes. then 10 after the canner was open. All the jars have a tight seal this morning. I will use them first just in case there is a reaction of the oil on the rubber seal.

One thing I didn't take into account last night. I had turned the temp down in the house and it was a little cooler than normal.

< using the weighted petcock>

So you canned it at 15 lbs.? That is the weight of the petcock - 15.5 lbs. Do you have to use 15 lbs? If so then due to the atmospheric pressure difference it takes 2x longer than the 10 mins. called for (not just 5 as you did) sitting in the canner with the petcock off for the pressure to equalize and for the lid to be removed.

Dave

No I canned it at 10. But since you mentioned it ... I wonder if I might have put the petcock on the wrong hole. I know I looked at it ... but maybe?! The jars were doing just fine until after I moved them. There was a lot of pressure in those jars!

Exactly what brand and model of canner are you using? Apparently it is a quite old canner if it still has a petcock but petcocks are not normally removable so it is impossible to put them on the wrong hole.

Do we just have a wrong term issue here - are you referring to a removable counter-weight - a weight that rocks/jiggles - rather than a petcock? A petcock has a valve you snap closed when at pressure and it only pops open when pressure exceeds 15.5 lbs.

Are you using the gauge to determine the pressure? If so they are often inaccurate so you could have been canning at a much high pressure than the gauge indicated.

Either way, if the jars were " spewing liquid out the lids" and dancing then they weren't allowed to equalize the pressure long enough in a still sealed, but venting, canner before removing them. It is fairly normal for lids to pop and release a few times but actual movement of the jars and spewing liquids is a symptom of severe pressure imbalances and that is a methods used isse.

Dave

wrong term issue! My Mother called it a petcock so I just thought that is what it was. It is the counter weight. (and yes it is an old friend I would hate to part with)

I agree that it is a pressure issue. My biggest concern is in it not happening again. I was really afraid that the jars would explode. ( What a fun mess and dangerous) I let the pressure come down. checked the weight and determined it ok to remove. then I let it set for 5 minutes. (it has been suggested 10 minutes-- I didn't recheck the instructions I will use 10 form now on.) The lid removed easily. no rush of steam. after 10 minutes I gently removed the first jar. It was slightly boiling. Removed all 6 jars turned away from the canner to the sink and then the first jar started releasing pressure. Did I have any advanced warning that I didn't see? What safety issues did neglect? The room was slightly cooler than I normal. My big question is why did it take so long to start? I am trying to understand so I don't get someone hurt.

That's why I asked what brand and model it is. If it is a gauged Presto - and I assume it is - then the counter-weight needs to be replaced with the 5-10-15 weight set to prevent it happening in the future. The gauges are notorious for being inaccurate and require annual testing to be used safely. There are many discussions here about this and the part needed (Part # 50332).

So the odds are you were actually processing at a higher pressure than 10 and as a result you would have needed to wait 10 after reaching zero to remove counter-weight, then wait 20 before removing the lid, then leave sitting in the canner until most all the activity in the jars ceased, and THEN when removing them make sure there is no drastic change in air temps (like a draft from an open window or such).

If it is not a Presto then it should have come with a weight set already in place rather than a counter weight.

Dave