I love collecting old jars. I love the colors, I love the old style of writing, I love the history behind them, and it reminds me of just how much work women did to preserve food and provide for their families. While these jars at one time functioned as a mundane, utilitarian vessel for food, now they are being used in all sorts of creative situations. Personally, I usually use my antique canning jars to hold flowers, both fresh and dried. A pretty ribbon around the top makes them look so cute! I do, however, purchase new jars for kitchen and food storage, which leads me to the topic of this post.
A while back, I mentioned that I kept finding shattered Ball jars in my upright freezer when I was getting stock out. I ended up with somewhere around a dozen shattered jars before I just gave up and ordered plastic deli containers specifically made for freezing. I didn't want to use plastic, but I was left with no other option. I was so confused about why my jars were breaking--I'd seen so many blogs from others who talked about freezing their broth in glass jars--that I took to scouring the internet for explanations and others who had experienced the same thing. And that's exactly what I found.
Turns out, many others had made the same mistakes as me. Someone, in one blog's comments, politely pointed out that the regular mouth jars seem to be most prone to breaking, but that NONE of the quart Ball jars are freezer safe. Sure enough, I went into the pantry and pulled down an old Ball jar box that I had kept, and it did state that the quart jars (all types) are not freezer safe.
Hmm.
Why on earth not?? You mean in all of our technology, we cannot engineer a freezer-safe glass canning jar? On GAPS, broths are too valuable to lose to broken jars, and I just can't chance drinking broth and finding a shard of glass when I try to swallow. Glass canning jars can withstand extremely high temperatures when canning, but they apparently become too brittle when frozen. Turns out, the shape of the jar might have everything to do with it.
Anyone who knows about jars (which is probably a group of about ten people on Earth and includes me) will understand that the shoulders of the jars are likely the culprit. Shoulders of jars are the curved or sloped shape of the top of the jar, at the spot where the jar opening narrows to accommodate the size of the lid.
Many folks are of the opinion that the liquid, which expands when it freezes, pushes against the curves of the top of the jar, creating too much pressure and not enough expansion room, thereby causing the liquid to push against the weakest part of the jars--the shoulders. There might be less chance of that happening with wide-mouth jars due to a less-pronounced shoulder, but I can say from experience that both the regular-mouth and wide-mouth jars will shatter. The only jars that are freezer-safe, according to the Ball jar box, are the jars with straight sides, like the jelly jars and half pint wide mouth jars.
No shoulders on this jar! |