Screwing the band on Jars before going into pressure Canner

[MNTaxi]

How tight do you screw the bands down on the lids befor putting them in the pressure canner? Do you tighten them down or leave them semi loose? None of my canning books specify and I have heard it both ways.

[GB]

You do not want to tighten them too much. The band is just there to keep the lip in place, not to seal it. If you tighten it too much then it possibly will not seal correctly. Just tighten enough until it grabs. No need to go any further.

[Andy M.]

Right.

The lid has to have enough room to move under the band to allow pressure to escape from the jar during the canning process. Then as the jars cool, the lid is sucked down and sealed by the vacuum in the jar. Once the jars are completely cooled, screw the band down until it is just snug. Not tight as a supermarket jar lid would be.

[Michael in FtW]

I believe that you will usually find the instructions say something like "snug but not too tight"

Originally Posted by NCHFP

• If rings are too loose, liquid may escape from jars during processing, and seals may fail.
• If rings are too tight, air cannot vent during processing, and food will discolor during storage. Over tightening also may cause lids to buckle and jars to break, especially with raw-packed, pressure-processed food.

DO NOT tighten the bands after processing!!!! This can break the seal formed during processing!!!

Originally Posted by NCHFP

Do not retighten lids after processing jars. As jars cool, the contents in the jar contract, pulling the self-sealing lid firmly against the jar to form a high vacuum.

This information comes from the National Center for Home Food Preservation (NCHFP), General Canning Information, Jars and Lids page.

[mcnerd]

Originally Posted by Andy M.

Once the jars are completely cooled, screw the band down until it is just snug. Not tight as a supermarket jar lid would be.

Actually the screw band should be removed completely. It is no longer needed.

If left on it could interfere with the seal of the flat lid, especially if it was screwed down against it or something was stacked on top that caused uneven pressure.

Only put the lid back on (loosely) when passing the jar as a gift so that your recipient will be able to have a proper lid once it is opened.

[MNTaxi]

OK, the reason I am asking is because when I canned the beef and tuna some of the liquid from nside of the jar escaped. Is that normal?

When I was shown how to tighten the band from the neighbor I thought he had them to loose. He basiclly screwed the ban and than stopped at the first sign of the ban touching the lid. If I wanted to I would be able to unscrew it with one finger.

[Katie H]

My experience has been that I just screw the rings on until I feel the first real resistance, then I tighten a little more. And, yes, some of the contents of my jars have escaped during the canning process. However, once they were removed from the canner and cooled, they "popped" as required and I tightened the rings the remainder of the way. Never had any problems with spoilage or illness.

[MNTaxi]

Yeah I havn't had a problem yet. Sounds like I have my bands just a tiny bit to lose. I think I will tighten them just a tiny bit more.

All my jars have popped as well except for the occational odd ball but we just eat that one right away.

[mcnerd]

Originally Posted by MNTaxi

OK, the reason I am asking is because when I canned the beef and tuna some of the liquid from nside of the jar escaped. Is that normal?

When I was shown how to tighten the band from the neighbor I thought he had them to loose. He basiclly screwed the ban and than stopped at the first sign of the ban touching the lid. If I wanted to I would be able to unscrew it with one finger.

Loss of liquid during processing has to do with the 'headspace' that is being purged, not how tight/loose the lids are. Sometimes with meats the headspace has to be an 1/8"-1/4" more than what the published recipe calls for because it seems to expand more during processing.

In fact, the National Center for Home Food Processing now recommends a headspace of 1-1/4" instead of 1" as published when canning chicken.

Loss of liquid does not effect the safety of the food though it is possible the seal may be compromised by food on the seal/rim so watch it closer for any indication of seal failure.

Note: A major loss of fluid in a jar usually is the result of a lid on too tight and the purging finally occurs in a big whoosh in the canner. The seal usually fails on such occurrences too.

[MNTaxi]

Thanks mcnerd for explaining that to me. I was border line 1" headspace. I will make it 1 1/4" headspace tomarrow and try that.

The seal part is what concerned me. Thats why I asked if it was common for the liquid to come out. I fell a little better now.

I will try adjusting the head space first and seeing how that goes.