Are Mason Jars Microwave Safe: A Detailed Answer

Mason jars are becoming popular, especially as a replacement for coffee mugs because they are affordable, aesthetically pleasing, and portable. However, they are very versatile and can be used for other purposes, including storing food in the kitchen or the fridge, heating food, and drinking beverages.

Mason jars are not recommended to use in traditional or microwave ovens for cooking or baking food because they are usually not made of tempered glass. Therefore, they cannot withstand high temperatures; and can break into pieces causing injuries to you. However, if your Mason jar has a microwave-safe symbol, it can go in the microwave without its lid.

Do you know if the Mason jars or microwave-safe or not? Read on know-how to find out if a Mason jar is microwave safe. You will also learn how to put Mason jars at what temperature and how long. Further, we will tell you the process of reheating the food in the Mason jars. 

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are mason jars microwave safe

How To Know That A Mason Jar Is Microwave Safe?

If your Mason jar has a microwave-safe label, it means you can use it in the microwave. The microwave-safe label is usually on the bottom of the Mason jar, but if you cannot find it, you can check the instruction manual or packaging. 

Moreover, this label means your Mason jar is made of tempered glass or other glass that can withstand high temperatures without shattering into pieces. Additionally, if your Mason jar does not have a microwave-safe label, it is best not to use it in the microwave. 

However, if you think your Mason jar is oven-proof but do not have the microwave-safe label, you can do the microwave test. For that, you have to put your empty Mason jar in the microwave for 1-2 minutes, and if it does not break, that means it is microwave proof.

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Further, try using small Mason jars for this test, and do not use thin or big Mason jars for the microwave test because you do not want them to shatter in your oven and damage it. Also, you will need to clean properly, even the tiniest glass bits of glass, to avoid contaminating your food in the future.

Moreover, if you decide to microwave the Mason jars, you should know that the glass can pick up heat, becoming very hot, making it difficult to remove from the oven. Therefore, use oven mittens or any other heat-resistant cloth to take them out of the microwave. Further, remove the lids (metal or plastic) from the Mason jars before placing them in the microwave since they may ignite.

Are All Glass Jars Microwave-Safe?

Most of the modern glass jars are microwave safe, but not all of them, especially older glass jars, cannot be put in the oven. Therefore, do not put every glass jar in the ven unless it has the microwave-safe label, is relatively new, or thick. Further, you can do the microwave test before using a glass jar in the microwave to be on the safe side. 

How Long Can You Microwave A Mason Jar?

The time you can keep Mason jars in the microwave depends upon their sizes. For instance, 1 to 2 minutes are enough for a 1-liter Mason jar, 3 to 4 minutes are enough for a 1 – 4 liter Mason jar, and about 5 minutes are enough for more than 4 liters Mason jar. 

Further, most people put Mason jars in the microwave to sterilize them; because it’s easier to fix them than on the stovetop. For this purpose, wash your Mason jars thoroughly with soap and warm water, and if they have any stubborn stains, you can use baking soda to clean those. After that, you need to fill the Mason jar with water and place it in the oven. Then microwave it for almost 1 to 2 minutes to kill all the bacteria. 

However, this method is not recommended because of safety concerns. It will be difficult to remove these Mason jars from the oven because the Mason jars pick up the heat, the water will also be boiling, and you can spill the water, causing burns. 

Therefore, be careful and use a kitchen towel or oven mittens to remove them from the microwave. However, if your Mason jars are not microwave-safe, you should never place them in the microwave.


What Temperature Will Break A Mason Jar?

The boiling water Mason jar can usually withstand up to 212 degrees Fahrenheit but the pressure canning Mason jar can bear up to 250 degrees Fahrenheit. However, the sudden change of temperature can shatter these jars into pieces. 

Therefore, continually heat them, or cool them down slowly to avoid sudden temperature changes. For instance, if you use a Mason jar in the microwave, heat it in small intervals and stir the food after every interval to avoid shattering and damage.

Read Also: Can You Wash And Reuse Aluminum Foil?

How To Reheat Food In Mason Jars?

You can only reheat food in the Mason jars in the microwave if they are microwave-proof. But you have to follow safety measures. You cannot reheat frozen food in the Mason jars because sudden temperature changes can cause the shattering of the glass. 

Therefore, you have to defrost the food before reheating it in the microwave. You can place the jar in the water for defrosting; keep changing the water until the food is defrosted. Further, it should be reheated at intervals of small temperatures so that the food temperature increases slowly and the Mason jars do not break.


To wrap it up, one could say that Mason jars can be put to use for different purposes in the kitchen, including freezing food in small portions, storing items, drinking beverages, and canning food. However, they usually cannot be used in the microwave because they cannot withstand high temperatures unless they have a microwave-safe label. 

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