Are Mason Jars Microwave Safe?
Edited by: Robert Swientek
Date: July 17, 2025
Yes, newer mason jars have a microwave-safe symbol on them. It is important to keep in mind that glass mason jars are non-reactive but still become very hot to the touch. For this reason, it's best not to package anything that requires long periods of microwave heating in mason jars. Use mason jars for quick-heat items like pre-cooked pasta, soup, cheese dips and other products that only require a few minutes to heat.
If your company packages freezable products in mason jars, disclaimers should be included that inform consumers not to thaw them in the microwave. Super-heated areas of glass may crack or shatter if the contents expand the jar. Metal rings, lids, and caps used to seal mason jars are not microwave safe.
Dishwashing
Mason jars can be cleaned in a dishwasher. However, repeated dishwashing may scuff the surface. For older jars, you may want to hand wash them to keep their appearance.
Oven
Mason jars are not designed for use in the oven. Empty jars may be sterilized in an oven but they should not be used for baking or oven cooking.
Freezing
Some mason jars have a freeze line embossed on the glass surface to show the limit of the contents for freezing applications. As a general rule, product should be filled to just below the collar of the jar. This is to prevent cracking of the glass due to expansion of the product during freezing.
Colored Jars
Colored mason jars—especially amber or blue—help block UV rays, which can degrade the contents of the jar over time. This UV barrier is particularly useful for light-sensitive products like herbs, essential oils, fermented products, and certain preserves.
In addition to their functional benefit, colored jars offer aesthetic appeal and bring a vibrant, vintage, or rustic touch to homes, restaurants, or event décor. In the home, their display worthiness moves them from the cupboard or closed pantries to open cabinets, shelves, and countertops.
Most modern colored mason jars are made from the same soda-lime or tempered glass as clear jars, which is generally microwave safe without the lid. They're fine for short, low-heat tasks, like reheating soup or melting butter.
Some colored jars, especially inexpensive or decorative versions, may be painted or coated, not colored glass. These jars are not suitable for microwaving because their coatings can bubble, peel, or release fumes in the microwave.
Like their clear glass cousins, look for the microwave-safe symbol on colored jars.
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