Can you Microwave Pyrex? [Solved]

Can you Microwave Pyrex?Despite many assurances by the manufacturer, some people are still uncertain whether they can microwave Pyrex. This may be caused by claims that Pyrex explodes or shatters when used in the microwave.

So can you microwave Pyrex?

Yes, you can microwave Pyrex. This is because, Pyrex unlike ordinary glass has more thermal and mechanical shock tolerance. How you go about it though, could make, or, literally break your Pyrex cookware.

What is Pyrex

Can you Microwave Pyrex?Pyrex refers to tempered glass which has greater thermal and mechanical shock tolerance compared to ordinary glass. While Pyrex is a brand name, it’s fair to describe it as that, since Pyrex was the first tempered glass to be used in cooking.

But what does thermal and mechanical shock tolerance mean, and how is it relevant to this?

Put simply, all matter expands and contracts when heated or cooled.

While this is the case with glass too, it has a distinct difference. Any sudden changes in temperature causes glass to expand and contract unevenly causing it to crack or shatter. Ordinary glass has relatively less tolerance to this thermal and mechanical shock.

Originally, Pyrex was made in the same way as its predecessor, Nonex, which was used to make signalling lanterns on railroads. Over time, the formula used to make Pyrex changed to pure sand, alumina, bore and soda, something which some critics argue, reduced Pyrex’ thermal and mechanical shock tolerance.

How to microwave with Pyrex

Step 1: Read the label on Pyrex

Before using Pyrex, ensure you check out the label that comes with it and confirm whether it is microwave-safe or not.

Similarly, check whether it is bakeware or glassware and use as appropriate.

Step 2: Fill Pyrex with food at least above the half level mark

Once you’ve confirmed the Pyrex is microwave safe, fill up the Pyrex dish or have the food or liquid at least half full on the dish, this is to ensure heat is distributed evenly to avoid any cracking or shattering.

If you’re warming up dry food, it’s important that you add a little liquid at the bottom of the dish, again, to ensure heat is uniformly distributed.

Step 3: Avoid sudden temperature changes

If the Pyrex dish you’re using has been in the freezer, or is just cold – let it sit at room temperature before putting it in the microwave. Alternatively, you can gradually raise its temperature by using the low heat setting.

If the microwave is hot, do not put in the cold Pyrex dish, gradually warm it up in the oven, or let it sit at room temperature before using it in the microwave.

Step 4: Removing Pyrex from the microwave

Once your food is properly warmed up, ensure you take out the Pyrex dish/jug using oven mitts, or if this isn’t available, use a dry piece of cloth.

Place the Pyrex in a cooling rack, or on a piece of dry cloth, or stack of dry paper towels. Never put the Pyrex on the countertop as it will cause the Pyrex to crack or shatter.


Ensuring mindful changes in Pyrex temperature

As stated above, while Pyrex has relatively more tolerance to thermal and mechanical shock, it goes up to a limit.

Earlier versions of Pyrex glass, pre-1998 were considered truly thermal shock-resistant since they were made using borosilicate glass, and could withstand sudden temperature changes. However, the current Pyrex glass is now made with Pure sand, alumina, bore and soda, and despite having more tolerance to thermal and mechanical shock cannot withstand sudden changes in temperature.

According to the manufacturer, Pyrex can work within a range of -400 and 3000 Celsius, with a thermal shock resistance of up to 2200 Celsius. However, you need to be careful when making any changes in temperature for your Pyrex appliances.

This means you need to:

Avoid subjecting your Pyrex to sudden temperature changes

In line with this do not transfer your Pyrex appliances directly from the oven/microwave to the freezer/fridge, and vice versa without allowing for any gradual cooling or heating up. Similarly, do not put hot materials in cold Pyrex appliances, or cold materials on hot Pyrex appliances.

Regarding cracked or chipped Pyrex

Avoid using a cracked or chipped Pyrex dish or jug in an oven or microwave, since heat will be distributed unevenly and may cause the Pyrex to crack or shatter.

When handling hot Pyrex

Use a dry oven mitt when removing Pyrex dish/jug from the oven or microwave. If you don’t have an oven mitt, you can use a dry piece of cloth. Further on this, once you remove a Pyrex dish/jug from an oven or microwave, do not place it on a cold countertop, rather, place on top of some dry cloth, cooling rack, or stack of dry paper towels.

When using Pyrex in a microwave

Fill up the Pyrex dish/jug slightly above the half mark. Doing this will ensure heat is uniformly distributed and prevents any risk of the Pyrex cracking or shattering.

What temperature is considered safe for Pyrex

According to the manufacturer, Pyrex can safely work within the range of -400 and 3000 Celsius, with a thermal shock resistance of up to 2200 Celsius. Any temperature that falls within this range is safe according to the manufacturer.

Pyrex safety and Handling Rules

Despite all the proof, and assurances that Pyrex is safe to use, Pyrex can still crack, dent or even shatter.

The thought of shards of glass in your oven, or worse, tiny shards in your food from cracks in Pyrex appliances should be enough to convince you to observe these rules:

Use of cracked or chipped Pyrex appliances

Never use cracked or chipped Pyrex appliances in the oven, or microwave. Doing this, may cause it to shatter, or worse, develop more cracks increasing chances of tiny shards of glass getting in your food.

Use an oven mitt when handling hot Pyrex

When removing a Pyrex dish or jug from the oven or microwave, ensure you use a dry oven mitt, or if this isn’t available, a dry cloth. This is to avoid scalding your hands and also to avoid subjecting the Pyrex to sudden temperature change which may cause it to crack or shatter.

Handle with care

Never hit or bang your Pyrex appliances on hard surfaces. Pyrex may have tolerance to thermal and mechanical shock, but it’s still glass and it can break.

Cleaning your Pyrex

When cleaning your Pyrex dish/jug using your hands, only use non-abrasive materials such as nylon. If you’re using a dishwasher, first rinse off any left-over food particles with warm water before putting it in the dishwasher.

Changing Pyrex temperature

Avoid subjecting your Pyrex jug/dish to sudden changes in temperature.

Avoid using Pyrex in direct heat

Never use Pyrex appliances on stovetops, grills or any other means that involves exposing the Pyrex to flames or direct heat. Unlike when using stovetops or grills, heat is generally distributed evenly in an oven or microwave, this prevents any sudden change in temperature and uneven expansion of Pyrex which may lead to cracking or shattering.

Faqs About Microwaving Pyrex

Can you microwave Pyrex with lid on?

Can you Microwave Pyrex?Yes, you can microwave Pyrex with lid on. Pyrex lids are not only heat resistant, but also free of BPA and dioxins, meaning you don’t need to worry about the lid melting or having potential carcinogens in your food.

Just remember to unlatch the lid from the dish to let out any steam from the dish as the food warms up.

Why did my Pyrex dish explode?

Your Pyrex dish exploded because you exposed it to sudden changes in temperature. This may be caused by either: cooking or reheating dry food on Pyrex, sudden changes in temperature, using a cracked or chipped Pyrex, or even not filling the Pyrex dish enough with whatever you’re cooking or reheating.

How do you stop Pyrex from exploding?

You stop Pyrex from exploding by following the manufacturer’s instructions. This includes, but is not limited to: cooling the Pyrex glass gradually before transferring it to the freezer and vice versa, and avoiding adding extremely hot substances to cold Pyrex glasses and vice versa.

Can you heat up Pyrex glass?

Yes, you can heat up Pyrex glass. According to the manufacturer, Pyrex is safe for use in ovens, and microwave ovens and thus safe to heat up. However, you should avoid sudden temperature changes which may cause the Pyrex glass to crack or explode.

Is Pyrex microwave safe, reddit?

Yes, Pyrex microwave is safe. However, you need to ensure you’re using low-thermal-expansion Pyrex. You may want to avoid the high-thermal-expansion tempered glass as it’s prone to cracking or exploding when used in the microwave.

Again, check the label on the Pyrex product and confirm whether the manufacturer states it is microwave safe or not.

Can Pyrex go straight from fridge to oven?

No because you run risk of the Pyrex glass cracking, or even exploding. The ideal way to do it would be to gradually warm the Pyrex glass, or even have it sit at room temperature for a while before placing it in the oven.

Can Pyrex glass go in oven?

Yes, Pyrex glass can go in the oven. The manufacturer states that all Pyrex glass can be used in an oven, freezer or microwave oven.

Can you heat Pyrex on stove?

Yes, you can heat Pyrex on stove. But this only applies to earlier versions of Pyrex, or those made in Europe since they’re made of borosilicate rather than tempered glass Pyrex made in Northern America.

Can Pyrex glass explode?

Yes, Pyrex can explode when subjected to sudden changes in temperature.

Pyrex glass behaves just like any other glass, only that it has enhanced tolerance to thermal and mechanical shock. Any actions that would exceed the tolerance limit would cause Pyrex glass to explode. This includes actions like: adding cold items to the Pyrex glass when hot, and vice versa. Similarly, transferring a hot Pyrex glass immediately to a freezer or a cold Pyrex glass to a hot microwave/oven would make it explode.

What is the highest temperature Pyrex can withstand?

The highest temperature Pyrex can withstand, according to the manufacturer is 3000 Celsius. Additionally, the manufacturer claims Pyrex can withstand thermal shock of up to 2200 Celsius.

Can you put boiling water in Pyrex?

Yes, you can put boiling water in Pyrex However, the Pyrex has to be either at room temperature, or you can slightly heat up the Pyrex before adding the boiling water. Remember, avoid sudden changes in temperature to prevent damage to your Pyrex.


You can microwave Pyrex, provided the manufacturer claims it is microwave safe. However, remember to always follow the manufacturer’s instructions and observe Pyrex safety and handling rules.

As you microwave your food in Pyrex, remember this.

Stay safe, and best of luck.

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