In many a culinary pursuit, whether it be making a shepherds pie, banana pudding, casserole or anything in between pyrex dishes are often used to cook a myriad of recipes. However, you may have seen or experienced horror stories of pyrex dishes exploding either upon being removed from or put in the oven. Naturally, this may make you question, is pyrex oven safe?

What Is Pyrex Glass?

Technically speaking pyrex glassware is a brand of glass dishes rather than a classification of glass dish. Pyrex cookware is the brand name for a type of heat resistant glass created in 1915 by the Corning Glassware Company. 

Back then, the type of glass used was borosilicate glass which was incredibly durable and perfectly able to withstand the heat of a hot oven. However, nowadays a pyrex glass pan won’t be made from this same borosilicate glass used in vintage pyrex. This is because eventually, borosilicate glass was phased out in favour of soda-lime glass which was cheaper to produce but is more brittle.

IS PYREX OVEN SAFE? - 5 ESSENTIAL TIPS FOR COOKING WITH PYREX GLASSWARE

Is Pyrex Oven Safe?

Since modern pyrex glassware will now be made from soda-lime glass instead of borosilicate glass there are questions regarding how durable hot glassware of this type will be. This is because there are plenty of horror stories of people’s pyrex glassware cracking or even exploding after being put in the oven.

However, contrary to what you may expect, this is not to do with hot glass being more brittle or anything like it. Instead, it is due to a phenomenon called thermal shock. Thermal shock being the result of what happens when glass cracks or shatters as a result of sudden temperature changes.

The effect of these extremes in temperature won’t just occur with a hot pyrex dish though. In fact, this can happen when warm pyrex is cooled very suddenly just as much as it can the opposite way around.

With this in mind, the vast majority of pyrex products can be considered to be perfectly safe for use in a hot oven. This being under the caveat that the pyrex glassware in question does not become subject to any sudden temperature changes.

Which Pyrex Products Are Oven-Safe?

Pyrex ProductIs It Oven Safe?
Pyrex BakewareYes
Pyrex Pie PlatesYes
Pyrex Mixing BowlsYes
Pyrex Measuring CupsYes
Pyrex Custard CupsYes
Pyrex Food Storage ContainersYes
Pyrex Lids (Glass)Yes
Pyrex Lids (Plastic)No

As you can see most of the products under the pyrex brand are considered oven safe. The only exception being the plastic lids which are intended for use during storage rather than when cooking.

Curious how to clean pyrex glassware? We can help with that!

How to safely use Pyrex products in the oven

Cooking with pyrex glassware inside the oven is a common weekly or even daily occurrence for many people. However, as mentioned, when doing so it is important to not expose a hot dish to sudden cold. Likewise, it is also important to not subject a cold dish to extreme heat. The consequences of doing so can be catastrophic and you may soon find yourself having to clean up a large amount of broken glass.

Tips For Using Pyrex Glassware Safely

When intending for a pyrex baking dish to go in the oven there are a few tips and tricks you can employ in order to ensure your best casserole dishes will last as long as possible. 

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Always Preheat Your Oven Before Putting In Any Pyrex Bakeware

Near enough, all pyrex glassware and products that are oven safe will have the words “pre-heated oven safe” engraved on them. As such, you can probably guess that whilst pyrex glass will be oven safe, this is only so when the oven has been preheated before the glass dishes were inserted.

The reason for this is that when the oven is heating up, it will not heat up at the same rate throughout. As such, when something is in the oven during this time it will begin to heat unevenly. 

Due to the potential of thermal shock, this is a big problem for glass bakeware. The reason being that the abrupt change in temperature between the edges of the glass and the middle can cause the glass to shatter.

Don’t Use Pyrex cookware With Your Stove 

Pyrex is as we’ve established perfectly safe for use in the oven. Additionally, it can also be used to reheat food in the microwave. However, it should never be used to cook on a stovetop hob.

The reason for this is actually quite simple, Pyrex cookware is not meant to be used to cook via contact with a direct heat source, such as fire. As such, Pyrex glassware should not be used on your stovetop, in a toaster oven, under a broiler or on your grill.

IS PYREX OVEN SAFE? - 5 ESSENTIAL TIPS FOR COOKING WITH PYREX GLASSWARE

When Cooking With Pyrex And Liquid, Be Very Careful

During the cooking process, liquid is often released from food. This can often be in the form of water, fat or juice amongst others. Either way though, they may cause an issue since when released from ingredients they will often be much colder than their surroundings.

As such due to the propensity for thermal shock that glass can have, it is best to add a small amount of liquid of the same temperature to the pyrex. Doing so creates something of a buffer zone between the glass container and any liquid from the food within. The result of this is that any variations in temperature between the pyrex and ingredients within the container will be mitigated, thereby reducing the likelihood of thermal shock.

An additional word of caution regards other types of liquid. For example, when using oven mitts to retrieve your pyrex from the oven, ensure that they aren’t wet as this may lead to thermal shock.

Once Retrieved From The Oven, Place The Pyrex On A Cooling Rack

An important measure to take in order to avoid sudden temperature changes is to place your pyrex on a cooling rack, woodblock or dry teatowel after removing it from the oven. This is to avoid it coming into contact with any cold and damp surfaces whilst it slowly cools to room temperature.

Even sharply dropping to room temperature after being subjected to multiple hundred-degree temperatures can mean glassware shattering. As such, ensuring it doesn’t come into contact with anything significantly cooler than that is essential to prevent your hot glassware from breaking.

Allow The Pyrex To Gradually Come To Room Temperature

As mentioned above, Pyrex should be allowed to gradually reach room temperature before being subjected to a change in temperature. This is true if transferring from the fridge to the oven or vice-versa.

Whilst this may take a while, the point of doing this is that the change will be gradual. Slow and gradual changes in temperature are crucial for glass containers of this kind to avoid thermal shock. As such, whilst this might seem annoying, it is unfortunately essential.  

IS PYREX OVEN SAFE? - 5 ESSENTIAL TIPS FOR COOKING WITH PYREX GLASSWARE

The maximum oven-safe temperature

Whilst pyrex is known to be oven safe, the limit of temperatures it can safely be subjected to is less commonly known. This is because no specific temperature has been given by pyrex themselves. Instead, they maintain that it is perfectly safe in any pre-heated conventional or convection oven at any temperature required to bake a recipe.

Despite this claim though many people find it to be somewhat dubious. As such, conventional wisdom surrounding the use of pyrex glassware suggests that you shouldn’t subject it to temperatures higher than 425°F (or 218°C).  However, even this number is up for debate as some claim the pyrex heat limit is actually higher.

Recommendations For Using Pyrex In The Oven

When using pyrex dishes in cooking, they can be used in the oven perfectly safely. However, when doing so it is crucial to avoid subjecting this glassware to any extreme temperature. This is because when subjected to such conditions, the resulting thermal shock may cause the glassware to crack or shatter.

In order to prevent this from happening your best off always pre-heating your oven before putting your pyrex dish inside, Additionally, when cooling, place it on a cooling rack or similar surface and allow it to gradually reach room temperature before doing anything else. Finally, avoid contact with direct heat sources or liquid as these can very abruptly cause the temperature to change.

Ultimately, pyrex cookware is incredibly versatile and perfectly capable of being used to both cook and store various foodstuffs. As such, how long it will last for you, mainly depends on how carefully you look after your pyrex.

FAQs – Can You Put Pyrex In The Oven?

How do you stop Pyrex from exploding?

Pyrex will only explode if subjected to extreme changes in temperature. As such, it is vital you avoid transferring it straight from the oven to the fridge or vice versa. Instead, they should be allowed to gradually acclimate to a different temperature.

Can Pyrex go straight from fridge to oven?

Pyrex should never be put in the oven straight from the fridge. This is because abrupt changes in temperature can cause the glass to crack or shatter due to a phenomenon called thermal shock.

What causes Pyrex dishes to explode?

Thermal shock is the phenomenon that causes pyrex dishes to explode. This phenomenon is caused by sudden changes in temperature which makes the glass suddenly expand or contract. As such pyrex should be allowed to heat up or cool gradually rather than abruptly heated or cooled.