Can You Freeze Mason Jars?

If you have mason jars lying around at home (and who doesn’t?), you’re probably wondering if you can fill them with stuff and put them in the freezer? 

Well, the answer is reasonably straightforward according to the experts that we asked. 


Can Mason Jars Be Frozen? 

Yes, mason jars (or maybe, bell jars depending on where you’re from in the United States) can be frozen.

In fact, you can expect the contents of a mason jar to tolerate being frozen for 3-6 months. 


How Can You Put A Mason Jar In Your Freezer Safely?

Frozen Mason Jar

Now, we’ve got that sorted – the question then becomes “how do you freeze a mason jar, safely?”

Well, there are two things you need to watch out for when it comes to freezing things in mason jars: liquid expansion and temperature control. 

Liquid Expansion

Water expands, unlike most liquids, when it is frozen. So, if you fill up a mason jar completely with liquid?

It’s going to crack in the freezer. 

Temperature Control

The other thing your glass jar is not going to like is a rapid change in temperature. So, if you pour boiling liquid in your jar and then pop it straight into the freezer?

You’re asking to crack the jar. 


How To Freeze A Mason Jar Safely

And this is the best way to avoid either of those problems or, indeed, any other arising as you freeze your mason jars. 

Pick The Right Mason Jar

The best mason jars for freezing have wide mouths and straight sides. That’s because they allow easy air circulation and thus, freeze easily.

Mason Jar

If you have mason jars with shoulders, instead, don’t worry, you can freeze them but make sure you fill them to a maximum level of an inch below the shoulder. 

Ensure It’s “Freezer Safe”

Not all mason jars are marked freezer safe, if yours aren’t – don’t freeze them. The lower quality glass in these jars can crack very easily in the freezer. 

Avoid Extreme Temperature Changes

Allow the contents to cool to room temperature before you put the jar in the freezer. 

If you’re worried about the contents being contaminated, seal the jar but don’t put the jar in the freezer hot. 

Don’t Overfill The Mason Jar

If you take a close look at the jar, you’ll find a line marked on it just before the cap line – it’s the freeze line.

We’d recommend filling your jar, so the contents are half an inch below this line. 

Don’t Use Lids That Will Rust

And don’t use a lid that can go rusty, because it will in the freezer and lead to contaminated food – always use a reusable plastic or glass lid, instead. 


What Do You Do If The Mason Jar Breaks In the Freezer?

Put some gloves on. Remove the jar and throw it out. Throw out the contents too. Don’t try and eat them or compost them as there might be tiny bits of glass in the mix. 


Final Thoughts

Reusing mason jars is an excellent idea. Just make sure not to break them. In fact, it’s a tip that could go with our guide on how to start a homestead with no money

You might also find our guides on how to dry herbs and which foods can’t be dehydrated useful, if you’re looking to extend the shelf-life of food at home. 

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