fried rice in vegemite jars on yellow tea towel

Meal prep in glass jars -can you put glass jars in the freezer?

Why Meal Prep?

Meal prepping and food preservation has become quite popular in the past decade with the influence of the fitness industry, however it is not a new idea. Homesteads and farms have always used meal prepping as a way to save food from going to waste that they have grown. It has been a way to keep seasonal food so that it is available all year round, prior to large supermarket chains importing it from all over the world. Personally, I find meal prepping to be a great way to have nutritious meals when I cannot be bothered cooking. Also, I use it as a way to re-use jars from the supermarket. It is much easier to make a large batch of food, once, and freeze the leftovers for another night, than it is to make it every couple of days. It is also a great way to keep your produce from going to waste- cook it up and you don't have to worry about your hard earned money going straight in the bin.  

fried rice in glass jars sitting on yellow and blue striped tea towel


Reduce & Re-use

When considering containers used for meal prep, if you are trying to reduce your consumption of plastic, you may be wondering "can you put glass jars in the freezer??" The answer to this question is a definite YES! Using jars for meal prep is particularly useful if you have a large chest freezer, but they can also be used in a smaller freezer, depending on how large your freezer is and how many other people you are meal prepping for.

One of the simplest ways to reduce your plastic consumption and to decrease the amount of rubbish going to landfill is to reuse what you already have. Here is where re-using  jars from the supermarket is a great idea. If you are anything like me, you have tried to reduce your rubbish and consumption of supermarket items, but you may still end up with plenty of extra jars at the end of the week- (I'm looking at you vegemite and peanut butter!!).


 empty glass jars in front of red crockpot on wooden coffee table

One great way to not have so many jars is by going to the bulk food stores and reusing the jars that you have- simply by taking the jars with you and putting your new produce in them. I have seen this waste reducing hack so many times being spoken about in other blogs, but unfortunately in Australia (at least where I live) there are very few bulk food places, and when they are available you are paying through the roof for the products. Now this may be fine if you are willing to pay the exorbitant prices that they are asking, and I wish that it was more affordable for the average Australian, because there is a lot to be said about supporting these kinds of companies that are trying to do the right thing by the environment, however I know that for a lot of people, the prices are just way too high. 

If you cannot avoid getting extra jars all the time, you can at least put them to good use. I have been reusing jars for years to store everything from dry goods in my kitchen and bathroom, to meals prepped in the freezer. In fact, most jars from the supermarket make fantastic meal prep containers, and can go from the fridge to freezer to microwave to dishwasher and back again. Multiple times. Of course there are caveats with this- in my years of freezing food in jars I have had one smash in the microwave, I'm not sure if it was due to already being broken from the freezer or the heat cracked it. Glass will break when stress is applied- rapid changes in temperature can stress the glass and cause it to expand and crack. 


How to choose jars for freezing

Personal experience has taught me that foods such as jams, pickles, and sauces tend to come in jars more suitable for freezing. Jars from these types of food are often the best to reuse as they are likely to be stronger and made to withstand wider temperature variations. 

vegemite, peanut butter, olives and pickles in jars sitting in front of red crock pot on wooden coffee table


Things to consider when freezing your food in jars:

  1. Ensure that the jars are properly clean and sterilised prior to putting food in them. You can run them through the dishwasher or wash in warm soapy water and let dry completely.
  2. Ensure the food is cold prior to putting in jars.
  3. Ensure jar is cold before putting in freezer.
  4. Fill jars below the widest point to allow for expansion. Soups etc, will expand more than something like rice, so how much you fill the jar will vary. Usually leave at least an inch for liquidous foods.
  5. Leave the lid off the jar in the freezer until the contents are frozen and then screw it on after the contents are frozen solid).
  6. Wide mouth jars are best for freezing food in especially soups and stews (vegemite jars are great as are peanut butter jars with wide mouths).
  7. Date and Label your contents so that you don't have to play guess this food!!! I use masking tape and a sharpie for this because it is easy to do and cost and waste effective, however you can make specific labels also.
  8. Be careful removing jars from the microwave (they get very hot very quickly!).
  9. Do not use jars that are from the dollar stores- stick with jars suitable for preserving or reused jars from the supermarket that have had preserves made in them.


How to Defrost Food Stored in Jars

The easiest way to defrost your food is to simply remove it from the freezer and sit it on the countertop (on a tea towel so that you do not get water from condensation all over your countertop) until it defrosts.

The second favoured way is to place the jar into a bowl of cold water. The cold water, being warmer than ice, but not too warn as to stress the glass, will defrost the food more quickly and you can then tip out the contents into a saucepan or microwave dish and heat.

The third and more risky way is to actually put the jar without the lid attached  into the microwave and microwave until the contents are hot. Do this at your own peril. This is not an advisable way of doing it, however it is something that I personally do often and do not usually have any issues with. I have only ever had one jar break. The jars however do become VERY HOT and you can risk burning yourself. It is definitely not something that a child should do!


If you have any great ways to reduce waste and reuse products from the supermarket, let us know in the comment section below..


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