Can You Freeze a Glass Jar? Top 5 Essential Safety Tips
Whether you’re trying to store leftovers or want to meal prep for next week’s breakfast, freezing food is a smart storage solution. But the quality of the storage container you pick can make a huge difference to the food you eat.
If you’ve been hesitant about freezing food in plastic containers or Ziploc bags, you might be thinking of using glass jars. But can you freeze a glass jar?
In this guide, we’ll help you find the answers.
Can You Freeze a Glass Jar?
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Yes, you can freeze a glass jar.
Glass jars are not just safe but also a much better choice for freezing food items and liquids when compared to plastic or other disposable containers.
What Are the Benefits of Using Glass Jars for Freezing Food?
For starters, glass doesn’t leach toxins into your food like plastic might, making it the better option for your health. It is also 100% recyclable so it’s healthy for the environment as well.
Second, glass has a better resistance to both heat and cold. So you can store hot liquids inside it without worry and also freeze it. What’s more, your glass jars won’t absorb odors or colors from their contents. So you can easily reuse them for storing a different food item later.
You can also get glass jars for free when you buy pasta sauces or jams. If you don’t, no worries! Glass jars are easily available for purchase at affordable prices.
Are There Any Drawbacks to Using Glass Jars?
Perhaps the only drawback of using glass jars for freezing is the risk of breakage and cracking. They are fragile. Thankfully enough, with the right practices and safety measures, the chances of breaking glass jars due to freezing are zero.
Don’t know what these practices are? Keep reading.
Tips and Tricks for Freezing Food (and Liquids) in Glass Jars
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1. Fill Three-Quarters of the Jar
The most common cause for glass jars to break upon freezing is pressure from the food or liquid inside.
Now, if you’re unaware, liquids expand when they freeze. This means they will take up more space when frozen compared to when they’re at room temperature.
And when you store gravy or liquids in a glass jar, it will try to expand to fill the glass jar. But if you store the contents to the brim with the lid tight, there’s no place for the liquid to expand. This will either result in the liquid spilling into your freezer or breaking the glass jar.
To ensure your freezer doesn’t have to suffer such an ordeal, make sure you only fill three-quarters of the jar. That way, the liquid will have plenty of space to expand. Both your glass jar and freezer will stay safe.
2. Check the Type of Glass Jar
Glass jars come in a variety of options from material quality to shape and design. And not all glass jars are an ideal choice for freezing food.
Glass Quality
Low-quality glass, also known as regular glass, is too weak to sustain both heating and cooling. They’re more likely to break if you try to freeze them. Such glass is often used in manufacturing wine glasses or tumblers.
Some much safer alternatives are borosilicate or tempered glass, which are often used in manufacturing plates, cookware, lab equipment, and canning jars.
If you’ve got a lot of canning jars lying around in the house, you might be wondering whether you can use those for freezing.
Yes, you can!
Canning jars are made from tempered glass. So they’ll work just fine for your needs.
The only consideration to keep in mind is that the quality of glass deteriorates as it ages. This makes old glass jars more likely to crack when frozen.
Jar Shape and Design
Can you freeze a glass jar safely irrespective of its shape?
If you’ve ever tried storing food in any container before, you may have already noticed that jars with wide openings make the task much easier.
In addition, you want to pick jars with straight sides or slightly conical walls. These shapes reduce the buildup of pressure when the liquid expands and thus reduce the risk of breakage.
They’re also easier to fill.
Jars with shoulders are also fine so long as you leave the recommended gap.
We do suggest you avoid jars with thin necks because they have a higher risk of cracking.
3. Don’t Tighten the Lids Completely
When you tighten the lids completely, the pressure in the jar increases, making it further likely that the liquids will spill. Or the jar will break.
To avoid this, make sure you’re only tightening the lids halfway when putting your glass jars in the freezer. Once the food inside has cooled completely (this can take up to 24 hours), you can tighten the lids to close the jar completely.
4. Let The Food Cool
When you’re preparing portions for next week’s meal prep, you’re probably going to have a lot of piping-hot food to store.
Now, remember that you can put the food in the glass jar while it’s still hot. But you need to let the food cool before putting the jar in the freezer.
You also want to leave the lid off while the food cools and instead cover the jars with a clean cloth. Once the food is cool, tighten the lids slightly and put the jars in the freezer. Then, let the contents freeze completely and tighten the lids to close.
Wondering if you can freeze a glass jar with high-acid foods inside? Yes, you can. But make sure you follow the boiling water bath method.
5. Freeze the Jars Standing Up
When you put your glass jars in the freezer, make sure they’re standing up. Avoid putting them on their sides, too close to one another, or stacking one on top of another.
This is to ensure the pressure from the expanding contents is equally distributed on all sides and the top remains clear. It also helps ensure the jars don’t bang against each other.
You also want to make sure not to stack the glass jars such that they fall out of the freezer when you open the door.
