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Can You Microwave Mason Jars?

Can You Microwave Mason Jars?

Mason jars are a classic food storage solution that you will find in so many people’s households, but can you microwave them safely?

You can microwave mason jars as long as they have a microwave-safe symbol on the bottom of the container. Remember to remove the metal seal and lid from the mason jar before putting it in the microwave, and never heat food items for more than five minutes.

Although most modern mason jars are microwave-safe, you should always confirm whether your specific jar can handle this kind of heat exposure before you place it in your microwave.

Are Mason Jars Safe to Microwave? 

Virtually all modern mason jars are safe to microwave. Mason jars have been around for over 150 years, and although they look as classic and original as ever, their glass technology has evolved with the times.

Modern mason jars are made with microwave-safe materials so that you can confidently and safely heat up food items. Older mason jars are more fragile and less stable, which means that you should avoid putting them in the microwave at all costs. 

Remember that only the glass of a mason jar is safe to microwave. Mason jars normally come with a metal lid and seal that will react to the heat of a microwave, potentially damaging the appliance. Make sure to remove any metal from the jar before putting it in the microwave.

How to Tell If a Mason Jar is Microwave-Safe

Since microwaves have become a standard appliance in most kitchens, companies have adapted to this change by making the majority of food products and containers microwave-safe. 

Mason jars are designed with a microwave-safe symbol located on the bottom of the container.

However, before you stick a mason jar in your microwave, confirm that it is safe to do so. Mason jars are designed with a microwave-safe symbol located on the bottom of the container.

The symbol generally has a picture of a microwave and a few wavy lines next to it to indicate that it can be safely heated in a microwave. 

Can a Mason Jar Break in the Microwave?

Mason jars can absolutely break in the microwave. This applies to all mason jars, including those that were made in recent years.

Mason jars have a breaking point when put under extreme heat for an excessive amount of time. Over the years, the temperature breaking point of these jars has been pushed considerably higher than before, which has resulted in these containers becoming microwave-safe.

However, “microwave-safe” does not imply that the glass is indestructible. The heat of a microwave can break any Mason jar, which is why you should only use the appliance for reheating.

How Long Can You Microwave a Mason Jar For?

As a general rule of thumb, you should never microwave a mason jar for more than five minutes. There are a number of factors that can increase or decrease the amount of time that you can safely microwave the jar, but if you keep it in there for five minutes or less, you should be fine.

How Long Can You Microwave a Mason Jar For

Keep in mind that this only applies to mason jars that are designed with a microwave-safe symbol. Older jars that do not have this symbol are harder to predict, and there is a greater risk of the glass cracking when exposed to the intense heat of a microwave.

However, you may also want to consider the size of your jar when determining how long it can be heated. Although five minutes is a safe estimate for most mason jars, I would recommend sticking to the following microwave times based on the size of the container:

  • Small jars (1 liter or less): 1-2 minutes.
  • Medium jars (1 to 3 liters): 3-4 minutes.
  • Large jars (3 liters or more): 5 minutes.

Can You Microwave Frozen Food in a Mason Jar?

You should never microwave frozen food in a mason jar. Although mason jars are great for reheating food, the container is put under increased stress when the contents are still frozen. 

When a mason jar begins to heat up frozen food, a part of the glass can potentially expand and crack. Most people that microwave frozen foods in a mason jar are doing so to speed up the thawing process. 

What Can You Safely Microwave in a Mason Jar?

So long as the food item you want to microwave isn’t frozen, doesn’t contain metal and takes less than five minutes to heat, you should be good to heat up just about anything. 

Microwaves were traditionally designed for reheating food. This implies that any leftovers, canned goods, and fridge contents should be safe. These are some examples of common food items that are safe for microwaving in mason jars:

  • Soups
  • Pre-cooked pasta
  • Lasanga
  • Chili
  • Stews
  • Dips

What Are the Risks of Microwaving a Mason Jar?

Mason jars can be a quick and easy solution to heating up various types of food items, so long as the container features a microwave-safe symbol. However, there are still some risks that you should keep in mind when microwaving mason jars. 


Mason jars get very hot, even if they have a microwave-safe symbol. The contents of the food will make the glass extremely hot, so remove the container cautiously from the microwave using an over-mitt.


If you’ve been around Microwaves long enough, you will know that metal does not mix well with these appliances. Given that these jars come with a metal lid and seal, remember to remove these components before heating.

Key Takeaways to Microwaving Mason Jars

You can microwave mason jars so long as they have a microwave-safe symbol on the bottom of the container. 

Before microwaving any mason jar, make sure to remove the metal lid and seal. 

Never microwave a mason jar for more than five minutes, as this can cause the glass to shatter.

Lindsay Reed

Hi, I'm the founder of! I created this website to be a resource for everyone who wants to make the best home possible.