Are Mason Jars Microwave Safe? | Safety Tips and Alternatives

Are Mason jars microwave safe? Many people are curious and asking this question about these classic glass containers. Mason jars have been around for years, serving various purposes from canning to decor. Let’s explore the safety aspects, other options, and common questions about using Mason jars.

Using the Microwave with Mason Jars

Most Mason jars are NOT microwave-safe. For example, the most sought-after brand of Mason jars is Ball®. Ball® canning jars are not microwave-safe.

Why? Ball® makes their canning jars from annealed glass, composed of soda, silica, lime, and cullet, and not from tempered glass, which is required to avoid breaking when heated in the microwave. According to the manufacturer’s instructions, Ball® does not approve the microwave oven at any temperature for their canning jars.

If a manufacturer labels their Mason jars as microwave safe, the glass has been tempered for thermal shock and is ok to use in the microwave. Some newer mason jars have a microwave-safe symbol, which means you can safely use them in the microwave.

What Does a Microwave-Safe Symbol Look Like?

Photo Credit: American Chemistry Council, Inc.

However, there are some safety precautions we need to consider even when using microwave-safe Mason jars. It is important to remember that when heating food in a Mason jar, you need to leave enough space for expansion to prevent pressure buildup. Since mason jars contain metal components like lids or decorative elements, you must remove them as they may cause sparking and damage to the microwave.

One of the biggest obstacles to using Mason jars in the microwave is that the jar gets very hot and is difficult to move safely. For this reason, it’s best only to microwave things that require short periods of heating in Mason jars. Use Mason jars for quick-heat items like butter, cheese dips, and other products that only need a few seconds or minutes to heat.

And most importantly, do not use the microwave to thaw frozen products in Mason jars! Super-heated areas of glass may crack or shatter if the contents expand the jar.

Practicing caution and following the proper guidelines while microwaving Mason jars is essential to avoid accidents and injuries. Selecting jars labeled as microwave-safe or explicitly designed for such use is your safest option.

Alternatives to Microwaving Mason Jars

To avoid the risk of thermal shock, and if you prefer not to microwave Mason jars, there are alternative options and methods for heating food:

• Microwave-safe Containers: Choose containers made of microwave-safe glass or ceramic specifically crafted for microwave use, like our favorite Rubbermaid Brilliance Glass Storage Set
  • Lids have a 100% airtight, leak-proof seal
  • The Smart Lid System lets you share lids across same-sized Brilliance containers of all material types
  • Lid vents let steam escape for splatter-free microwaving
  • Glass bases are oven-safe up to 450 degrees F
• Stovetop Heating: Utilize pots or saucepans on the stovetop for precise temperature control when heating food, like Hexclad.
• Plastic Containers: Opt for microwave-safe plastic containers for quick and convenient food reheating. Our favorite plastic containers are Rubbermaid Brilliance BPA Free Food Storage Containers.
  • Designed to be leak-proof and airtight
  • BPA-free
  • Microwave-, freezer-, and dishwasher-safe

Checking these alternatives can help you discover safe and efficient ways to warm your meals without risking using your Mason jars.

Dishwasher and Mason Jars

Most Mason jars are dishwasher-safe. However, it is best to check the manufacturer’s guidelines. Since repeated dishwashing will scuff the surface, you may want to hand wash them to keep their appearance.
Removing metal lids or rubber seals before placing the jars in the dishwasher is essential to prevent rusting and ensure thorough cleaning. Make your Mason jars even more multi-purpose with dishwasher-safe reCAP Mason Jar lids.

Mason Jars in the Oven

According to Ball®, “We do not recommend using Ball canning jars as bakeware.”

Some Mason jars may be oven-safe and can withstand high temperatures. People have commonly used Mason jars for baking desserts, such as cakes and pies.

To prevent thermal shock, be sure to avoid sudden temperature changes.
Upgrade your baking experience with this Made in USA bakeware set from Pyrex, which is perfect for cakes, cookies, and more.

Can You Put Mason Jars in the Freezer?

Mason jars are freezer-safe. You can store soups, sauces, and other foods in the freezer.

To allow for expansion, leave enough space at the top of the jar as the contents freeze. Make sure to use wide-mouth jars for easier removal of frozen foods.

Seal your wide-mouth Mason jars with these convenient plastic caps Ball Wide Mouth Storage Lid Leakproof from Amazon.

For more information on freezing food in mason jars, check out our post, “Can You Freeze Mason Jars? At-A-Glance Tips for Freezing Your Food.”

Additional Information

Whenever possible, we strongly recommend consulting the manufacturer’s instructions. If such instructions are unavailable, the following general information should prove helpful. For more amazing Mason jar ideas for cleaning, crafting, and cooking, check out our blog post: 25 Amazing Mason Jar Ideas for Cleaning, Crafting, and Cooking.