Does anyone do their canning in jars that have glass lids?

[moolie]

... Or maybe I'll wait and let you experiment and report back!

Lol, I guess I'm the guinea pig on this one, but I'm so super intrigued to try it

 

[hoosier]

I would experiment with a few jars of an item where I could spare some losses, then keep a close eye on them over the next couple of months.
I would use a product that would not be compromised by additional cooking such as tomatoes for soups. That way, you could reprocess if you knew for certain they didn't seal.
Goog luck and let us know.

 

[Bubblingbrooks]

... Or maybe I'll wait and let you experiment and report back!

Lol, I guess I'm the guinea pig on this one, but I'm so super intrigued to try it

The rings are zinc oxide, I believe, and are not considered safe today.

 

[miss_thenorth]

I have a handful of the jars and tops too, handed down from the older crowd at my mom's church. But I don't have the metal screwtops or the rubber seals. I just have few out for decoration.

 

[moolie]

The rings are zinc oxide, I believe, and are not considered safe today.

Hmm, really? Zinc oxide is a white powder (ZnO) and not a metal, and it is used as a mineral food additive and also in sunblocks.

As for zinc safety, I myself take zinc lozenges when I feel a cold coming on, and if I take it quick enough (within 12 hours of infection) I never end up with much more than a day or two of sniffles. I'm also told by my doctor that zinc is an anti-oxidant and having enough zinc in your system makes wounds heal faster.

Anything I've ever read about not using zinc canning lids has always referred to the one-piece caps, rather than bands that don't come into any sort of direct contact with the food. My understanding is that the porcelain lining inside the one-piece caps can crack and some of the old linings may contain lead--thus the warnings about not using old zinc caps. Plus the seal can't be tested as it can with the two-piece zinc ring/glass lid combo (take the ring off and lift the jar by the edges of the glass lid similar to how you test flat metal lids).

That said, I just tested and the glass lids fit under the modern rings I have so it may all be academic anyway.

Oh, and I picked up two boxes of rubber rings at Canadian Tire this morning so I'm all set to go when my pears are ripe enough!

 

[valmom]

Those are really cool! Can the rubber rings be re-used for future canning, or are they like the flat metal lids that are only good for one good boil?

 

[moolie]

Those are really cool! Can the rubber rings be re-used for future canning, or are they like the flat metal lids that are only good for one good boil?

From what I've read so far, they can be re-used.

 

[DrakeMaiden]

Are those considered "3-piece closures" with glass lids? If so . . . an old food preservation book my mom has says that the seals are especially vulnerable to jostling and bumping, and it is generally recommended to leave the screwbands on after canning. I should see if the book mentions anything else. My mom and I were debating whether it was proper to remove screwbands from modern metal lids and she just gave me a photocopy of one page from her book. Not sure if the jars you have would be considered "3-piece closures."

 

[DrakeMaiden]

OK, my mom's book says that your jars are indeed the "3-piece closure" glass lids. It says to apply the rubber ring when it is wet. It says that the screwband is turned down tight, then given an 1/4 inch (I leave the conversion to metrics to you . . . I'm short on time, sorry) counterturn to allow air in the contents to vent while processing. Re-tighten the band carefully as you remove the jar from the processing kettle, but never re-tighten further afterwards. That is all it says.

A word about zinc -- The book also talks about zinc lids that are lined with porcelain to protect the food from contacting zinc. If the porcelain is damaged you shouldn't use the lids because exposure to zinc could mean that food is also exposed to cadmium. So it isn't the zinc itself that is the concern, but the cadmium that is usually found with the zinc. Since the screwbands are not in contact with the food, it probably isn't an issue.

 

[JRmom]

I did a search today and there are tons of the zinc lids for sale... so I guess people aren't keeling over from canning with them. I don't see how they could be a problem as long as they are in good shape, the lid does not come into contact with the food at all.

I do have one Mason jar that has the lid with the porcelain liner, and yes, I can see how the food could come in contact with that one.