Can You Microwave Mason Jars? – Quick Informational Guide

Mason jars are basically glass molded jars that are used to preserve food. YES you can microwave mason jars, BUT it depends on a number of factors; One of the most important factors is the age of the jar. Older jars are unsafe for microwaving as they would easily shatter under high temperatures.

Another important factor is whether there is a microwave safe symbol on the jar. A lot of mason jars may have this symbol but there are a few without this symbol. Therefore, it is very important to check the jar for this symbol prior to microwaving.

Here are some precautions to take before microwaving mason jars:

Despite the fact that most mason jars may be safe to microwave, it is important to know that during microwaving the glass can still pick up heat making it hard to get the jar out of the microwave. BE CAREFUL!

The mason jars are perfect storage containers of food for long period of time. But over time the mason jar lids and rings can corrode, making it difficult to remove the ring hence the food becomes inedible.

Most mason jars are made of a soda-lime glass which does not flex well. As you know we all like to do a quick defrost so that we can eat something fast or cook something at a particular moment.

It is highly advisable not to microwave frozen food stored in mason jars. During the process of heating up the glass temperature rapidly changes from minus zeros levels to plus levels which causes the glass to expand rapidly. This extreme change in the structure of the glass can definitely cause the glass to shatter.

The best solution to this is to place the mason jar in a bowl of cold water and microwave it. Occasionally take the bowl and mason jar out of the microwave and change the water in the bowl. Keep repeating this process until the contents of the mason jar are defrosted and heated up to your desired temperature.

Now obviously all the mason jars glasses, whether new or old, will heat up and it would be difficult to handle them. In this case, always have a small kitchen towel or heat resistant glove to take the hot jar out of the microwave.

In general, glass is the best material for microwaving because it is non-reactive, unlike metal that will give off sparks when microwaved. This is possible with a sealed mason jar. The lids of the mason jar are metallic in nature, so, therefore, can be dangerous to microwave. YOU MUST remove the lids before placing the mason jar in the microwave!

Another good material that is perfect for microwaving is porcelain. Porcelain does not pick up heat, and transmits the heat poorly. Therefore, porcelain is perfect for all kinds of microwaving from frozen food and mildly hot foods. But be careful with porcelain containers that were low fired. This kind of porcelain is very weak and can explode in the microwave.

Aluminum foil is a very unsafe microwave material. Aluminum is a good reflector of microwave radiation. Therefore, putting aluminum foil in a microwave will create a counter radiation effect that might explode the entire microwave.

Unfortunately, a lot of food is stored in aluminum foil because of its good reflective abilities of heat radiation that keep food hot.

Here is a list of things you cannot microwave:

1: Stainless steel in travel mugs:

The heat will be blocked from warming the liquid and it can damage your microwave.

2: Chinese take-out boxes:

The metal handles and plastic can start a fire.

3: Styrofoam Containers:

Styrofoam is a type of plastic and plastic is potentially dangerous.

4: Plastic containers: The chemicals like Bisphenol (BPA) in plastic could end up in your food.

5: Grapes: They can catch fire.

6: Plastic bags: These are unsanitary, can cause a fire and emit toxic fumes

7: Eggs: The rapid heat builds up pressure in the egg which causes it to explode.

8: Pepper: The chemical released from them can sting your eyes and burn your throat.


The mason jars are perfect for storing food but it is always safe to check the container for microwave safety or just get the food out of the container, put it on a porcelain plate and microwave it. Simple.

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