Can you freeze food in glass jars?
I get this question almost every time I post a photo of frozen applesauce, soup, broth, or jam.
And the answer is: YES.
You can certainly freeze food in glass.
But, you must, must, must be certain to leave plenty of headspace (empty space) at the top of the jar so that the food can expand as it freezes.
(This is assuming your food has water in it. If you froze something like almond flour in a glass jar, there is no need to leave headspace.)
I like to err on the side of caution and leave more headspace than I think I will actually need.
Do you need special glass jars for freezing?
You can get Mason jars made specifically for freezing; these have a neck that just gets wider at the top rather than becoming narrow.
This makes them less prone to breakage when food expands as it freezes.
However, as long as I leave headspace, I have not had a problem using my regular-mouth Mason jars for freezing food.
I just err further on the side of caution when leaving headspace in the non-freezer jars.
What kind of glass jar lids work for freezing?
I use all sorts!
The two-piece lids intended for canning work just fine, and so do the plastic Mason jar lids.
I’ve also used powdered Parmesan cheese lids on narrow-mouth Mason jars, and they survive the freezer just fine.
Can I freeze food in glass jars I save from grocery foods (such as spaghetti sauce glass jars)?
Yes, this can work, but I can’t wholeheartedly recommend them.
I notice that jars from grocery foods often seem to be made of thinner glass than actual Mason jars, and I have had a few break on me in the past just from normal temperature changes.
So, I typically only reuse these jars for storing refrigerated liquids or for making homemade yogurt.
Sometimes, canned fruit comes in hardy glass jars that seem comparable to real Mason jars, and those do work well for freezing.
How do you thaw food in glass jars?
The smartest thing is to think ahead so that you can let the jar sit at room temperature or in the fridge until the food is thawed.
(Do I always think ahead? No.)
If you neglect to think ahead, you can use the defrost setting on your microwave to thaw the food. Just make sure to remove the metal lid first!
It’s tempting to run the glass jar under hot water to help speed the thawing process, but a fast temperature change like that can cause glass to break. Resist the urge.
What kind of foods do you freeze in glass jars?
I typically freeze:
- homemade broth
- homemade applesauce
- homemade freezer jam
- extra spaghetti sauce
Do you have any other questions about freezing in glass?
If so, let me know and I’ll answer in the comments or add to the post.
And if you have tips about freezing in glass, do add those in the comments as well!