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May 16,2015
Freezing In Canning Jars,
Whether you plan on freezing leftovers or following a “freezer style” recipe, there are some questions that usually come to mind.
Which jars can I freeze in?
Jars that do not have shoulders ( ones that are straight sides or "tapered" ) are the easiest because the contents can expand upward in the jar during freezing, especially if you’re freezing liquids (jams, jelly, soup, broth, etc). You can use other food grade jars, as long as the expansion of the food isn’t a problem. We often freeze single serving sizes of grilled chicken, beef BBQ, or meatballs in other jars since the straight sides really aren’t a requirement.
Jars with necks ( sauce & woozy bottles etc. ) are not recommended, as the contents will expand upward into the part of the glass with a smaller diameter causing breakage. If the description of the jar doesn’t mention that it is safe for freezing, double check with your supplier.
Which lids should I use for freezing?
You’ll want to use a lid with a plastisol liner or a foam liner to create a good airtight seal. This is a great time to re-use your already spent flat canning lids or single piece lids because all you need is a good seal to keep flavors in and air out! The single piece lids are nice for jams and products that you will be getting into often.
How much can I put in a jar?
Allow enough headspace for the expansion of your product. Some, but not all of the Ball jars have a “FOR FREEZING——FILL HERE” line embossed on the glass. A general rule of thumb for any jar is to only fill to a little below the collar of the jar.
Remember most food grade glass exhibits a 90-degree thermal shock differential! When canning, you can’t pour hot contents into a cold (or sometimes even room temperature) jar. For the same reason, you shouldn’t expose your jarred frozen items to sudden heat. Set them on a dish towel or paper towel on a plate or tray (to hold/absorb the melting condensate) and allow thawing in the refrigerator overnight, or on your counter if you are able to monitor them. If you need to speed up the process, you may set them in a few inches of lukewarm water. Do NOT try to microwave a frozen jar.
Related FAQ:
Q: what is the benefit of freezing over just canning?
A: Good question. It really depends on what it is you are trying to preserve. It also comes down to personal preference.
Q: How do you know if the jar is air tight? It says above: all you need is a good seal to keep flavors in and air out. Does that mean to just screw the lid on? I’m used to freezing in plastic bags where I squeeze the air out – but have decided to start freezing in canning jars.
A: Yes, just screw the lid on tight and put it in the freezer.
Q: How do you know if the jar is air tight?
A: If there are not chips in the rim of your jars and the lids you are using have a good plastisol, silicon or rubber liner, you should have a good seal. The 2-piece metal canning lids should have that ring of plastisol, that if screwed on properly should provide a tight enough seal to prevent leaking.