If you’re wondering… Can you freeze a mason jar? Then the answer is yes, absolutely, you can freeze mason jars without breaking them if you follow the right steps carefully.
Mason jars can be extremely useful in the kitchen. You can save empty containers from shop-bought goods or buy them in whichever sizes you want. Saving old ones makes a lot of sense as it helps to reduce waste and doesn’t cost you anything extra.
Whether you like to batch cook, make your own stock or keep leftovers in the freezer, mason jars are handy for any of those reasons. It’s convenient and toxin-free.
Freezing in plastic might leach chemicals into your food, which can be carcinogenic and harmful to your family. BPA, a common component of plastic products is suspected of leaching into food and affecting the brain and prostate gland of fetuses, infants and children.
You do get an increasing number of BPA free products. But there are still other chemicals that lurk around plastic containers. That’s why many families are proactively choosing not to use plastic wherever possible, especially for storing food.
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So back to the question; can you freeze a mason jar? Let’s have a look at the 7 steps to freezing in mason jars below.
How to Freeze Mason Jars the Right Way
It’s quite easy to end up with broken mason jars if you’re not mindful or aware of what might be breaking them. Temperature shock and overfilling can both be culprits. Breaking jars can be avoided with a few easy steps:
Step 1: Cool the contents of the jar
Make sure you cool the contents of the mason jar before freezing. It is a good idea to cool the food before adding them into the jar as well to avoid burning yourself if you spill the contents. Warm foods freeze more quickly and can break the jars, which we don’t want!
Step 2: Don’t overfill the jar
Don’t fill mason jars to the top, about 3/4 of the way will be adequate. If you’re using a mason jar with “shoulders” don’t fill above them. Most newly bought mason jars will give you an indication of how much to fill them for freezing. Liquids will expand when they freeze generally so give foods a bit of space to do so
Step 3: Freeze without a lid first
If you’re worried about how much you’ve filled the mason jar, put it in the freezer without a lid and then close it once frozen. You can also put the lid on loosely at first so that some air can escape and firmly close once frozen. Make sure you place the jar on a saucer just in case, if you’re leaving it open
Step 4: Use wide-mouthed mason jars for freezing like these from Ball, who have been making canning jars since the late 1800s (it’s probably the one your grandma may have used for canning)
Step 5: Make sure you’re using mason jars that can be frozen like these from Ball as mentioned. Or if you’re saving shop-bought mason jars the ones the twist-off cap jars used for honey, jam, fruit, pickles, sauces or other vegetables will work well. Tempered glass containers will also work well for freezing.
Step 6: Don’t cram it into the freezer. Leave space between the jars and other items or the freezer sides so that it doesn’t touch other frozen objects as the varying temperatures can cause problems for your mason jars
Step 7: Add a label with a date, so you remember what’s inside and how long it’s been in the freezer. Frozen foods can look similar and it’s so easy to forget what is what! These labels are quite handy for labelling food.
What Types of Food can you Freeze in Mason Jars?
Most foods that freeze well, in general, can go into mason jars if you don’t overfill them and carefully follow the steps outlined.
- Things such as juices, berries and other fruits freeze well. If you’d like to make sure fruit do not stick together once frozen you can freeze them by spreading them out on a baking sheet and then place them into mason jars once frozen
- Leftovers and sauces such as soups, stews, fruit purees and baby food work well. It’s a good idea to only part cook bulky food such as lasagne, pizza and pies so that you don’t overcook them while reheating
- You can safely freeze uniced cakes and sponge type deserts
- Vegetables should be blanched (boiled briefly and cooled quickly) before freezing
- Bread, biscuits and pastry dough, butter and pre-shelled nuts all freeze well
- Full fat dairy such as cheese and milk can also be frozen quite easily. Grated cheese is better than a whole block, as a solid block will need more time to evenly defrost in the fridge once you’re ready to use it
Top tip: Portioning foods before you freeze them is a good idea as it’s usually difficult to separate or portion food that is frozen. As individual bits have a tendency to stick to each other. And unfortunately, re-freezing food such as meat once defrosted isn’t recommended so planning ahead can be super helpful.
Foods that Don’t Freeze Well
Not all foods are suitable for freezing, whether in a mason jar or any other container these are things like:
- Leafy vegetables
- Fresh tomato and salads
- Cooked eggs
- Low-fat dairy products
Defrosting Foods in Mason Jars
If you are planning on defrosting, placing your frozen foods in the fridge and leaving it overnight is a wise choice. Alternatively, leave the sealed container in lukewarm (not boiled) water to defrost or pop it in the microwave on the defrost setting. Avoid refreezing things especially raw meat and fish unless you’ve defrosted it raw and cooked it once it’s been defrosted.
How Long Can you Freeze Food in Mason Jars?
Because foods you can freeze in mason jars are sealed with an airtight lid, they should keep well in the freezer. But how long you freeze it depends on how brave you are, we’ve personally forgotten about foods in the freezer for ages and still cooked it and it was fine. Meat that has picked up freezer burn is not nice once cooked so take it out before that happens, otherwise, it will taste terrible. Dairy products and fish is recommended for a month or so. Have a look at this article for a guide on recommended freezing times, but you can use your own judgement as well.
Reheating and Cooking Foods from Frozen
To get the food out of your mason jars, leave them in the fridge or in a bit of warm – not boiling – water so that the sides can loosen. Most foods, other than joints of meat or poultry, can be cooked from frozen. Once you’ve removed the foods from the mason jar either gently reheat the contents on the hob or in the oven with a lid on. Then turn the temperature up as desired to cook fully. You can boil frozen pasta directly or heat it up in the microwave.
If you’re placing your jars in the microwave, start with a lower heat or the defrost function to warm the glass gently. Then turn the heat up.
What to do about Rusty Lids?
On occasion, you might get rusty lids, especially when using low-quality mason jars. Re-purposing shop-bought jars will definitely reduce the risk of rusty lids, or that is our experience anyway, you can get rustproof lids like this or a plastic option like this.
As the food shouldn’t be touching the lid, the chances of chemicals leaching from a lid are reduced so, in theory, it shouldn’t cause any issues with toxicity.
Mason jars are very robust and super handy in the kitchen, not only for freezing but they are also super useful for storing foods in general. Reusing store-bought jars is a good zero waste tip as it helps to repurpose jars that otherwise would’ve been thrown out, hopefully, to be recycled. Even though glass is widely recycled, the process still uses energy so it’s always best to reuse it if you can.
We’re big fans of freezing in mason jars and organising the pantry and storing anything from flour to nuts and cereal in glassware. The added bonus is that you won’t need to worry about toxicity from plastic or other coated storage material. Even though plastics are deemed to be safe, you really never know as our understanding of toxins that are hiding in materials are still limited.
Follow the steps outlined in this article carefully and you’ll be able to freeze in mason jars without breaking them ever again!