Can You Microwave Cold Pyrex?

If you often find yourself working late hours, then chances are you spend a lot of time preparing meals in the microwave.

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Whether that be reheating leftover takeout or cooking one of the many microwave meals you have stored in the refrigerator. These days, microwaves can even be used to make delicious recipes or bake a variety of tasty cakes.

However, this does not mean that microwaves do not come with their limitations, as there are certain foods and materials that should never be reheated.

For example, if you ever store your leftovers in pyrex dishes, then you may think it’s fine to microwave them in their containers, which is not always the case. So if you have ever wondered if you can microwave cold pyrex, then you have come to the right place.

In the following article, we have gathered some important information concerning cold pyrex and whether it can be used in the microwave.

We will also explain how you can microwave cold pyrex safely without causing damage to your home or health. So if you are ready to learn more about this material and its limitations, then we have everything you need to get started…

Can You Microwave Cold Pyrex?

If you want a short and simple answer to this question – then no, you cannot put cold pyrex in the microwave.

Though it has been claimed by manufacturers that pyrex is both microwave and freezer safe, this does not mean that cold pyrex is suitable for the microwave, as the contrast in temperature can lead to some serious reactions.

As a material, pyrex is considered to be thicker and stronger than normal glass, which makes it the perfect material for cooking and storing food.

However, if you have stored your pyrex dishes in the freezer, then placing them in a preheated microwave could change the temperature of the glass at a rapid speed, which can have a negative impact on the structure of the container.

Because of the sudden change in temperature, the pyrex glass could suffer from shock and shatter within a few minutes, which is why you should refrain from microwaving pyrex dishes that have recently been taken out of the freezer.

If you want to know more about the ins and outs of microwaving cold pyrex, then we have gathered some important information in the following sections.

Is It Dangerous To Microwave Cold Pyrex?

During a press release, the manufacturers of pyrex assured the general public that their products were microwave safe, even though you would have to follow the instructions provided with the product.

Unlike ordinary glass, pyrex is thicker and harder, which makes it the perfect material for producing cookware and containers.

However, this does not mean that pyrex does not come with its limitations, as you still have to be careful when using the material in the microwave.

This is because the appliance uses electromagnetic waves and it is not specifically mentioned on the company’s website. In fact, the official website states that pyrex can shatter when exposed to a sudden change in temperature.

This means that the material can be used in the microwave or freezer, although you will have to be wary when transferring your pyrex dishes from a cold environment to a hot one.

Because of this, the dish could explode and shatter into pieces, especially if the pyrex has been kept in the freezer and suddenly moved to the heat of the microwave.

Similarly, warm pyrex should never be put into the refrigerator, as the thermal shock caused by the sudden decrease in temperature could fracture the glass.

Can Cold Pyrex Break In The Microwave?

As we previously discussed, cold pyrex can break when placed in the microwave, as the glass cannot withstand the drastic change in temperature.

This is because pyrex dishes are made from a substance called borosilicate glass, which can be used in the microwave when following the necessary precautions.

When borosilicate glass experiences a sudden change in temperature, it undergoes what is known as a thermodynamic reaction. This process refers to the thermal shock that occurs when the dish is moved from one extreme temperature to the next.

For example, when a cold pyrex dish is heated rapidly in the microwave, this will make the glass expand at different rates and cause stress to the composition of the material.

Of course, you can avoid shattering the pyrex dish by slowly changing the temperature once it has been removed from the freezer.

While raising the temperature and placing the microwave on a low power level, you will be able to heat up your pyrex dish without causing damage to the structure of the glass.

However, if you introduce cold pyrex to the microwave without gradually raising the temperature, then the glass will shatter due to the instant transition in temperatures.

How To Microwave Cold Pyrex

When it comes to microwaving a cold pyrex dish, it is recommended that you allow the container to rest at room temperature, instead of removing it from the freezer and putting it directly into the microwave.

According to guidelines sanctioned by the USDA, all perishable food items should be cooked, reheated and frozen within 2 hours, which means the food needs to be stored in that time to make it safe for consumption.

Because of this, you can place your cold pyrex dish on the kitchen counter for around 15 minutes, which will give it enough time to normalize its temperature.

Alternatively, you can also place the dish in a bowl of hot water to achieve the same result. When the food is warm, you can then place it in the microwave and reheat your meal.

If you choose to forego this method, then placing your cold pyrex dish in the microwave could help to fracture the glass, which would endanger your health and render your food inedible.

The safest way to microwave pyrex dishes is by slowly bringing the container to room temperature and then putting it into the microwave on high heat.

Tips For Microwaving Cold Pyrex

Since microwaving cold pyrex can be a dangerous process, you will need to make sure that you are using the correct instructions when approaching the task.

Instead of placing the cold dish directly into the microwave, there are numerous methods that you can use to gradually raise the surface temperature of the cookware.

So if you are interested in microwaving a cold pyrex dish, then we have compiled some helpful tips in the following section:

Remove your pyrex dish from the freezer.
Place the dish on a flat surface at room temperature for 15 minutes. For the best results, we recommend resting it on a kitchen counter.
If you want to speed up the process, then you can do this by taking a large container and placing the pyrex dish inside.
Alternatively, you can fill a large pot with hot water and place the pyrex dish inside it until the glass is warmed up.
You can also put the pyrex dish in the sink and run the warm water for a few minutes until the glass has normalized, you will not need to use boiling water to complete this process.
Warm up the water with the pyrex dish inside it until the temperature has increased to room temperature.
This should only take a few minutes and then you should end up with a warm pyrex container that is ready to be put in the microwave.

However, it should be noted that the previous tips should only be used to increase the temperature of the pyrex and not the food inside it. In this case, cold pyrex is the danger and not the leftovers you intend to reheat.

Final Thoughts

In conclusion, you should never microwave cold pyrex, as this could lead to the glass shattering due to thermal shock. For this reason, you will need to handle the glassware carefully, so that you can ensure the best results.

While pyrex dishes are made from thicker and stronger glass than other popular cookware brands, this does not mean that they don’t come with their limitations, which is why you have to be careful when placing the material in the microwave.

Pyrex has even assured that their products are microwave and freezer safe, although there are certain guidelines that you will have to follow.

So if you want to know what these guidelines are, we have listed them for you down below:

Before you can place your cold pyrex dish in the microwave, you will need to rest the dish at room temperature.
Pyrex products should never be placed on the stove or used in conjunction with appliances such as toasters, electric burners, boilers or BBQ grills.
The bottom of the pyrex dish should be coated with liquid, as this will minimize the risk of the glass shattering due to sudden changes in temperature. For example, you should always moisten the dish with the juice from the food or with melted fat or butter.
However, you must never add liquid when the pyrex dish is hot, as this could drastically change the temperature and crack the glass.

So be careful when placing cold pyrex in the microwave, as the material is prone to cracking when exposed to sudden changes in temperature.

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Jess Smith

Hi, my name is Jess Smith, and I love cooking in my spare time. Around three years ago, I decided to give up my day job as a teacher to pursue my passion for food. While I have enjoyed sharing tips and tricks on Social Media, I have decided to expand my horizons through this blog.

Through this blog I hope to help others learn the basics and more intricate details of cooking. I know from personal experience how frustrating it can be to cook a meal, only to realize you are missing one ingredient from your list. This is why I love to write articles chatting readers through some great substitutes that can be used in an emergency.

I hope you will find this blog useful, and that it will help you to develop your culinary skills, to help you cook up a storm!