Can You Microwave Pyrex Glassware?

The quick answer is that Pyrex Glassware can be microwaved. It may, however, suffer from thermal shock if it travels too fast between hot and cold surfaces.

Let’s have a look at how to microwave Pyrex glassware without breaking it.

See also: Can You Put Cardboard in the Microwave?

What Is Pyrex?

Pyrex is a brand of long-lasting glass cookware that can endure high temperatures. Corning Glassworks Company first produced this tough glass for railroad signal lamps in 1908.

Jesse Littleton, a physicist with the business, took a glass piece to his wife, who used it to make a cake, in 1914. Corning began producing and selling glass cookware under the Pyrex name in the United States once it became clear that the glass could resist high temperatures.

Pyrex gained a household brand in the United States in the 1930s, owing primarily to the automated manufacturing method, which resulted in greater supply and decreased production costs. Pyrex has been a popular option for glass bakeware ever since. Its versatility for microwave cooking expanded the brand’s appeal in the following decades.

However, the composition of Pyrex has evolved significantly over the years, and it is no longer constructed with the same ingredients as it was in its early days. Let’s take a closer look at how Pyrex glassware is created and how it has evolved throughout the years.

What Is Pyrex Made Of?

Pyrex glassware was generally produced of borosilicate glass until the 1940s, a form of glass that has been treated with ingredients such as boric oxide or silica. These materials strengthen and protect the glass.

Tempered soda lime glass began to replace borosilicate glass in Pyrex dishes in the 1940s, and the US manufacturer now solely utilizes tempered soda lime glass for Pyrex dishes.

Let’s take a closer look at how borosilicate and tempered soda lime glass vary.


Borosilicate glass is resistant to high temperature fluctuations and is often used in glass laboratory equipment. Because of its strong thermal shock tolerance, it is ideal for baking, storing, and serving food.

Borosilicate glassware is ideal for removing a dish from the oven and placing it on a cool surface.

When Pyrex was initially introduced, the glassware was constructed entirely of borosilicate glass. However, this is no longer the case.

Pyrex, a US company, progressively began to incorporate tempered soda lime glassware to its collection and eventually discontinued creating borosilicate glassware entirely in the following decades.

Tempered Glass

Tempered soda lime glass is very strong and resistant to high temperatures. The glass is heated to a very high temperature and quickly cooled under great pressure during the tempering process.

The procedure makes the tempered glass very tough and resistant to impact, such as being dropped on the counter. Tempered glass is relatively safe and has minimal potential of inflicting cuts when it shatters as a result of this technique.

Tempered glass, on the other hand, has a lower tolerance for thermal shocks, making it more prone to breaking due to temperature fluctuations. That means leaving a tempered glass baking dish on the counter after using it in the microwave is a poor idea.

What Are Some Ways to Use Your Pyrex?

Pyrex plates may be used to cook or heat food in microwaves and ovens. Furthermore, not all meals may be digested in a single sitting. That overabundance of food, on the other hand, will not go to waste! Put it in the Pyrex and put it in the freezer!

Pyrex may be used to keep food in the refrigerator and freezer. Pyrex bowls may be used to hold raw or cooked meat or vegetables, soups, and sauces. However, allow your meal (and Pyrex dish) to get to room temperature before placing it in the refrigerator or freezer.

Pyrex is also dishwasher safe.

Is It Safe to Microwave Food in Pyrex?

Yes, you can microwave meals in Pyrex glasses. Because it is composed of strong glass, it will not shatter and will cook your food evenly.

You should not, however, microwave cold Pyrex. This is because the heat shock might fracture your dish, leaving you with a mess to clean in your microwave.

Make sure that:

  1. You do not pour anything hot into a cold Pyrex.
  2. You let your Pyrex get back to room temperature before putting it in the microwave.
  3. A hot Pyrex dish should never be placed on a cold surface, such as a damp or chilly counter, the refrigerator, or the freezer. Keep in mind that your dish may still be quite hot if you remove it right from the dishwasher.
  4. Examine for cracks. If your Pyrex dish has fractures, it may break in the microwave.

Also see: Best Microwave Covers (A Must-Have in Every Kitchen).

Different Types of Pyrex Dishes

Pyrex offers a wide range of glasses for use in the kitchen. Here’s a list of some of their products and whether or not they can be microwaved safely.

Glass Bowl Storage Jars Measuring Cups
Microwave safe  Many size options to choose from   Rectangle dishes   Dishes come in clear glass, which helps you see what you stored in them   Not microwave safe  Bamboo lid option   Elongated containers   Great pantry organizers     Microwave safe  Easy to read markings in both metric and oz.   Dishwasher safe with no fading   Has different size options.

Is Vintage Pyrex Different Than Current Pyrex?

Vintage Pyrex may be constructed of borosilicate depending on the year of manufacture. Corning, the firm that manufactured Pyrex until 1998, had begun replacing borosilicate glass with tempered soda lime glass in the 1940s.

Nobody knows when Corning ceased utilizing borosilicate in its Pyrex dishes, although borosilicate had grown rather costly to make because to air pollution rules in the 1980s. As a consequence, most US manufacturers discontinued making borosilicate glass cookware.

If you want a Pyrex dish that isn’t constructed of tempered soda lime glass, you may have to look around for antique Pyrex made of borosilicate.

There are also aesthetic distinctions between old and contemporary Pyrex. Pyrex now makes a line of kitchen necessities out of soda-lime glass, but they used to make everything from carafes to casserole plates, gravy boats to custard cups.

These plates were available in a variety of colors and patterns, and new sets were launched each year for the New Year’s and Christmas holidays. These dishes have a devoted following among antique collectors.

You might try your luck at a local thrift store to add some colorful and microwaveable cookware to your collection.

Borosilicate Glass Alternatives to Pyrex

If you desire borosilicate glassware for your kitchen, you have a few options: Borolux, a firm established in the United States, sells borosilicate glass bakeware that can withstand heat shocks.

If you live in Europe, you have a few choices for borosilicate dishes. In Europe, borosilicate glass is still used since soda-lime glass has not yet been adopted.

Simax Glassware, located in the Czech Republic, manufactures baking pans out of lab-grade borosilicate glass.

International Cookware also sells baking pans and measuring cups made of borosilicate glass.

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