Are Old Pyrex Bowls Microwave Safe?

Pyrex bowls are made to endure high temperatures without any physical damage. The material is specially used for cooking and baking by withstanding extreme temperatures.

The only concern when using Pyrex bowls is that there might be a risk linked with glassware when cooking food in a microwave. So, are old Pyrex bowls microwave safe?

Yes, old Pyrex bowls are microwave safe. However, make sure to bring the bowl to room temperature before placing it in the microwave. Moreover, ensure that the bowl doesn’t have any metallic detailing because metal sparks up in the microwave.

Other than this, you should never place old vintage Pyrex bowls in the microwave empty. Always add a little water to the bottom of the bowl before microwaving food that might release water.

Why your Pyrex cracked

A few users might complain that their Pyrex glass cracked while being heated. Such incidents are caused by suddenly heating cold-refrigerated Pyrex; the sudden change in temperature causes damage to the Pyrex glass, causing it to break or crack.

Inversely, extremely hot, freshly microwaved Pyrex should not be kept in the freezer as the sudden change in temperature also causes damage to the Pyrex glass.

Ergo, it is safe to microwave Pyrex glass, but certain precautions should be followed before microwaving to avoid any unwanted incidents.

Best way to microwave Pyrex

The safest and most effective way to microwave Pyrex is by progressively preheating the bowl, soup plate, cups, etc., rather than submitting it to extreme heat all at once.

As stated earlier, the user should ensure that the dish they purchase is microwave-safe by reading labels, symbols, or the producers’ recommendations that determine that the dishes are microwave safe.

For meals that release steams, the first step is to add some water or moisture to make sure the dish is not left dry, and it is preferable not to reheat the Pyrex glass often. Here are a few labels for better understanding!

Is ceramic microwave safe too? Find out now!

Can new Pyrex utensils go in the microwave?

New Pyrex utensils are safe to use in the microwave as long as they have the microwave-safe label.

Pyrex is a thick and heat-resistant glass that is able to survive in high temperatures. However, not all glass is microwave safe. Therefore, it is recommended to always check for labels or symbols that indicate that the Pyrex glass is microwave safe.

Talking about glass in microwave, we suggest you read our article on whether glass mason jars are microwave safe or not.

Here’s what your Pyrex bowls are made of

Raw materials like boric oxide and silica are heated at high temperatures for protracted periods. The soft, molten material is then used to make different kinds of glassware. The most common elements of Pyrex are stabilizers, fluxes, and formers, as we discussed above.

Formers are composed of crystalline materials that are heated to melt at high temperatures and then further cooled to make glass.

Flux are materials that help to achieve a certain melting point by decreasing and maintaining the temperatures.

Stabilizers secure the glass from any damage and protect the glass from breaking, cracking, and disintegrating.

You may also like: Are microwave bowls oven safe?

Concluding thoughts

After discovering all about Pyrex bowls, we conclude that Pyrex is microwave safe. Pyrex gives better security while microwaving or under extreme temperatures because they are made up of thick, double-layered glasses.

So, you can use your Pyrex dishes in the microwave without any worries, but remember not to directly put your cold dishes in the microwave because the temperature change can be harmful!

Rate your thought on this post
Photo of author
Immad Amir
I'm Immad, a passionate home chef and the proud curator of RavvyReviews, a kitchen appliance & food blog. Through my blog, I share expert tips all aimed at inspiring fellow food enthusiasts to embark on their culinary adventures with confidence and creativity. I love interacting with you guys, do share your thoughts in the comments. Get in touch with me through
We use cookies in order to give you the best possible experience on our website. By continuing to use this site, you agree to our use of cookies.
Privacy Policy