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Glam Journal

Why do we use Pyrex glass for cooking?

Author

William Burgess

Updated on February 28, 2026

Why do we use Pyrex glass for cooking?

Pyrex was made to withstand high heat and won’t ever shatter—so can Pyrex go in the oven? Back then, you could safely take a dish from one temperature extreme to another—refrigerator to freezer to oven—without having to worry about glassware shattering from the change in temperature.

What makes Pyrex special?

In a glass composition, this extra strength gives it thermal and chemical resistance that makes it useful for cooking applications, thermometers, and laboratory equipment. Pyrex also has a low alkali content that gives it high corrosion resistance.

Why is glass used for cooking?

Courtesy the Corning Museum of Glass. During the early 20th century, glass wasn’t used for cooking because it couldn’t withstand extreme temperature fluctuations. Instead, cooks relied on earthenware, cast iron, or tin vessels that could be heated easily.

Can I bake in Pyrex?

Pyrex® Glassware can be used for cooking, baking, warming and reheating food in microwave ovens and preheated conventional or convection ovens. Pyrex Glassware is dishwasher safe and may be washed by hand using non-abrasive cleansers and plastic or nylon cleaning pads if scouring is necessary.

Is Pyrex safe for health?

The safety concerns of most types of cookware are based on some pretty thin evidence. For everyday cooking, very little evidence actually suggests that metal or enameled pans are dangerous to health. And glass/Pyrex and clay cookware is almost certainly safe.

Is cooking in glass safe?

Glass cookware is quite safe if it is new and handled to prevent breakage. Some not so healthy components used in the production of glass such as lead and cadmium leach into food during the cooking process.

Is Tempered glass good for cooking?

According to Pyrex’s safety and usage instructions, “While the glass is designed for temperatures typically used in baking, it can break when exposed to the direct heat element while the oven is preheating.” Don’t use tempered-glass bakeware on the stovetop, under the broiler, in a toaster oven, or on a grill.

Can you bake in vintage Pyrex?

Now… a lot of vintage Pyrex was developed expressly for the purpose of cooking in the oven. So, in most cases cooking a casserole in your Pyrex in the oven should be fine – that’s often what it was meant for! Many modern Pyrex items will denote whether they are safe for the microwave on the bottom of the item.

Is all Pyrex oven safe?

The Short Answer. The short answer is yes; Pyrex glassware is completely safe to put in a preheated oven. But, Pyrex plasticware, including the plastic lids that come with the glassware, are not oven-safe. The plastic lids are designed for storage only and will melt if you put them in the oven.

Why is Pyrex glass used as a cooking glass?

It can absorb heat very quickly and because of its low expansion coefficient will maintain its shape and mechanical properties over a very wide range very safely. The glass can be produced in a very wide range of thicknesses without a great fear of setting up large internal stresses from temperature variations.

What happens if you put a Pyrex dish in the oven?

But what many folks don’t know is that somewhere along the line, things changed, and Pyrex glassware is no longer thermal shock-resistant. If used improperly, the dish can shatter into hundreds of tiny pieces inside your oven—leaving you with a potentially harmful mess.

Do you have to take care of Pyrex glass?

As with all glass products, you must exercise an appropriate degree of care, especially when cooking food at high temperatures.

Can you use Pyrex in a microwave oven?

Pyrex is a famous brand that can be used to cook, bake, or reheat food in microwave ovens and preheated conventional ovens. Even more, you can toss Pyrex into the dishwasher or wash manually by hands using non-abrasive detergents. The Pyrex brand takes pride in the production of heat-resistant kitchenware.

It can absorb heat very quickly and because of its low expansion coefficient will maintain its shape and mechanical properties over a very wide range very safely. The glass can be produced in a very wide range of thicknesses without a great fear of setting up large internal stresses from temperature variations.

When did Corning start using Pyrex for cooking?

In 1909, Corning began marketing its borosilicate glass products as Nonex or CNX (Corning Non-Expansion). Eight dishes from the first set of Pyrex, circa 1915. Courtesy the Corning Museum of Glass. During the early 20th century, glass wasn’t used for cooking because it couldn’t withstand extreme temperature fluctuations.

What happens if you put a Pyrex bowl in the oven?

Stove tops and broilers conduct heat quickly, and will likely cause the bowls to fail. Taking a bowl directly from the freezer and putting it into a hot oven might also trigger breakage. Are Pyrex Bowls Dangerous? Maybe. Pyrex bowls were originally made of something called borosilicate glass, which is very resistant to thermal shock.

When did Pyrex clear glassware first come out?

Pyrex clear glassware was introduced by Corning Glass Works (now Corning Inc.) in 1915. At that time, Corning used a special borosilicate glass that resisted the expansion and contraction that occurs during quick, extreme temperature changes. Not only was it exceptional to cook with, the glass was ideal for laboratory glassware and railroad lamps.