A Pyrex glass dish with an aqua lid from above.

Is Pyrex Microwave Safe? Everything You Need To Know

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I love cooking (obviously), but spending Christmas morning chopping and stirring just didn’t sound appealing to me this year. So the other day, my friend was over to help me knock out some brunch prep ahead of time.

Along with about 20 other things, we were working on my famous homemade cinnamon rolls. After a quick rinse, I handed her the pyrex measuring cup I used earlier . “Here,” I said. “Melt the butter in that – one less dish to load into the dishwasher!” She put the butter into the measuring cup, and as she was about to load it into the microwave, she hesitated, turned to me, and asked: “Is Pyrex microwave safe?“.

It’s a pretty common concern. At that moment, I reassured her that, yes, for melting butter, Pyrex was totally fine to use in the microwave.

Now, at this moment, I’m here to reassure you, too! Pyrex is generally microwave safe- however, there are a few caveats.

What is Pyrex? What is Pyrex Made Of?

Maybe the most iconic kitchenware brand of all time, Pyrex makes all kinds of kitchen accessories: measuring cups, mixing bowls, baking dishes, food storage, and more. Known and loved for their durability, what their products are actually made of depends on how old they are.

Older Pyrex products are made from borosilicate glass – the same kind of glass you would find in a chemistry lab. Modern Pyrex products are made of soda lime glass or tempered glass , the hardy glass that a lot of windows and phone screen protectors are made from.

Which one is better? It’s hard to say, as they both have strengths and weaknesses. Tempered glass has less heat resistance than borosilicate glass, but it’s also a lot more durable. Borosilicate glass, on the other hand, breaks easier, but it can withstand higher temperatures.

Is Pyrex Glass Microwave Safe?

Yes, Pyrex glassware is microwave safe, so long as you follow the same rule of thumb you would use when you microwave regular glass: don’t microwave it if it’s cold. 

All glass, Pyrex or not, is prone to cracking or even exploding with sudden, drastic temperature changes. Heat in microwaves is interesting as it is truly an uneven heating method – without getting into the science your Pyrex may have hot and cold spots throughout the heating process.

And, of course, before you just toss your Pyrex into the microwave willy-nilly, it’s wise to double-check your dish for the microwave symbol on the bottom. If you don’t see one, play it safe and use something else.

Is Vintage Pyrex Microwave Safe?

Given the high monetary or sentimental value (or both) of your vintage Pyrex, disregard everything I just said and exercise EXTREME caution here. Or, even better, just keep your vintage pieces away from microwave ovens. 

In theory, vintage Pyrex is microwave safe, but in practice, it’s a pretty big gamble.

First, the older the piece, the more likely it is to have chips or cracks. Even if you don’t see any, it’s possible that you missed one. Chipped or cracked Pyrex is much more likely to explode, and then you’ll have a costly replacement to buy and a hazardous cleanup job on your hands.

Then, there’s the risk to the design on the exterior of the dish. Since a lot of vintage Pyrex pieces were produced when microwaves were more of a luxury item, the designs weren’t made to hold up under those conditions.

Some vintage Pyrex pieces even have gold leaf on them, which should definitely not be microwaved.

Are Pyrex Storage Bowls Microwave Safe?

If you’ve got some takeout leftovers calling your name, then no need to dirty another dish – Pyrex storage containers are totally microwave safe. Just leave the dish out for 15-30 minutes before you nuke it.

If you used Pyrex storage bowls for freezer meal prep, it’s a little more complicated. Don’t curse yourself, though. You didn’t know better, and it’s easy to rectify. (PS I highly recommend using glass containers for all food storage, ad plastic food storage containers can possibly leach chemicals – and stain.)

For frozen leftovers, all you need to do is let them thaw before you throw it in the microwave. You can leave it on your countertop, or you can soak it in a bowl of cool water first.

Then, wipe off the moisture/condensation and microwave it like normal! Easy, peasy, make-ahead mac & cheesy.

Can You Microwave Pyrex With a Lid?

Totally. Both Pyrex’s glass lids for their older casserole-style dishes and their lids for their more modern food storage products are microwave safe.

If you’re microwaving a casserole dish with a lid, like all their other glass products, just take extra care that it’s not really cold. Truly, though, I can’t think of a situation where your casserole lid would be cold enough to give you issues. These glassware plastic lids are pretty sturdy. In fact I have an abundance of them in my cabinet as I’ve dropped a few of their counterparts. 

Plus the plastic-y lids BPA-free, so no need to worry about toxicity, and unlike other plastics that melt in the microwave, they’re heat resistant. Plus the BPA-free plastic lids come in many color combinations to match your kitchen aesthetic perfectly. 

A Pyrex glass dish with an aqua lid.

Do’s and Don’ts for Microwaving Pyrex

So, by now, you know you shouldn’t go straight from the freezer into the microwave. But that’s not the only thing to keep in mind when you’re nuking Pyrex. Here are some more handy-dandy do’s and don’ts.

The Do’s

1. Find the manufacturer’s recommendations for your piece. If you’re able to do this, then those should supersede anything else on this list.

2. If you can’t find the recommendations online or in the owner’s manual, make sure your piece is microwave safe by looking for the symbol on the bottom of the dish. If you can’t find that, play it safe and use something else.

3. Turn down your microwave’s power level. Your Pyrex is much less likely to crack in the microwave if it’s heated for a long time at a lower temperature.

4. Let dishes from the fridge warm up on the countertops before you heat them up. The chance of cracking is low if the contents aren’t frozen, but it’s better to be safe than sorry.

5. Wipe away any condensation or excess moisture on the dish before you microwave Pyrex.

The Don’ts

1. If it’s cracked, put it back. The odds that your Pyrex will shatter in the microwave are much higher if there are existing chips or cracks. Honestly, a cracked or chipped piece is best used for display only.

2. Don’t crank the heat. Microwaving your Pyrex dish at a high temperature for long periods of time puts a lot of stress on the dish and can cause it to crack.

3. No moisture = Broken Pyrex. Don’t microwave anything too dry, as rapid temperature can change suddenly. Adding a little bit of water to the dish will moderate the temperature and keep your Pyrex in one piece.

How Long Can I Microwave Pyrex?

If you can, look to your owner’s manual for an answer specific to your piece.

But if you can’t do that, it’s better to turn your temperature down and microwave your dish for a long time than it is to do the opposite.

In essence, letting your dish heat up gradually is the key. How long you microwave it for doesn’t matter as much as drastic, sudden changes in temperature do.  If microwaving for a significant amount of time, use oven mitts to handle the hot glass. 

Why Did My Pyrex Break in the Microwave?

Oh no! Do you have a Pyrex-plosion on your hands? You’re probably wondering how that happened if Pyrex is microwave safe. RIP to nana’s iconic casserole dish.

The truth is, even though Pyrex is microwave safe, it’s not microwave proof. It was probably a sudden spike in temperature that led to the demise of your dish.

Maybe you moved it too quickly from the fridge/freezer to the microwave. Or maybe there wasn’t enough moisture in the food you were heating up. It could have even been a small chip or crack in the dish that escaped your line of sight.

Whatever it was, there are steps you can take to ensure it doesn’t happen again. Follow the guidelines laid out in your owner’s manual closely. And if you don’t have them, then just heat low and slow next time.

A Pyrex glass dish sits in an open microwave.

Is Pyrex Oven Safe?

We’ve established that Pyrex is appropriate for heating up leftovers or ingredients. But what about, say, cooking a casserole in it?

Yep, that’s a go too, so long as you stay within the range of safe use. Pyrex is conventional oven safe up to 425F. – use those oven mitts! 

Of course, all the rules about microwaving Pyrex still apply. Don’t put cold Pyrex in a hot pre-heated oven. That means if yo want to bake a frozen casserole: thaw it out first. Even if it’s been in the fridge, let it warm up on the counter before you pop it in the oven, or put in in the cold oven to preheat together.

If you’re baking a cake or other dish that you’d expect to rise in the oven, it’s important not to use the glass lid that your dish comes with (if it comes with one, that is). Not only could this keep your creation from rising, the lid could also dislodge in the process.

The same also applies to toaster ovens, although I’d keep a VERY watchful eye on the temperature if you plan to do this. Place the Pyrex away from the direct heat element as direct contact with heating elements will subject the glass to the extreme temperature changes we are actively avoiding. In my experience, toaster ovens heat up pretty quickly, which could mean the end for your Pyrex. 

While Pyrex glass is oven-safe, it is not stovetop-safe. Gas and electric burners are direct heat sources which equals sudden temperature changes which equals broken glass.

Can You Freeze Pyrex?

If you’re a meal prep master, you’ll be happy to hear that Pyrex is great for freezing meals or ingredients. I have a Pyrex dish full of homemade chicken stock that I dip into all the time.

Just follow the reheating instructions for frozen foods I laid out up above, and you should be golden!

I’ll also add here that you should always let hot food cool down before you move it from its pot pan into Pyrex and put it in the fridge or freezer. You’ll keep the food from getting soggy from condensation, but not only that, you’ll also keep the temperature of the Pyrex from changing too rapidly.

Best Ways To Clean Pyrex

You’ve reheated and thoroughly enjoyed your leftovers, but now your Pyrex is covered in caked-on residue. But have no fear…Pyrex is as easy to clean as it is to use. Here are some easy ways to get that Pyrex shining.

1. Soap, sponge, and elbow grease: Hand-washing is the most obvious choice, and it definitely gets the job done. However, I would do this carefully; it’s pretty easy for heavy Pyrex dishes to slip out of wet hands and chip.

2. The Dishwasher: Pyrex is dishwasher safe, with the exception of some of the vintage pieces. It can go on either rack of the dishwasher, save for the plastic lids, which should go on top.

3. Magic Eraser: They really are magic, aren’t they? You can scrub stubborn baked-on foods off your Pyrex with the help of a magic eraser. Once again, though, be cautious with vintage pieces. A Magic Eraser could easily take the color/designs off their exterior.

Pyrex In the Microwave: Final Thoughts

Pyrex is generally microwave safe as long as you use good judgment and exercise some basic caution. Don’t subject Pyrex to sudden changes in temperature, and make sure to get rid of any chipped or cracked pieces.

But also, don’t let those viral videos of exploding Pyrex trick you into thinking your microwave and Pyrex is a deadly combo. With everyday use, you should have little trouble following these guidelines and staying safe.

About Author

TiaGoodnight

Hey! I'm Tia, and I started this site to bring you the best information on all things kitchen so you can enjoy and elevate your everyday life.

I love trying new techniques and tools, living for the thrill of pulling off a new skill. On weekends you'll find me at the local farmer's markets or hosting friends and family for an evening of yard or card games and delicious food.

If you're looking for honest, real-world advice on all things kitchen and cooking, you're in the right place!