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Your grandmother’s kitchen is probably hiding some very valuable collectibles without your even knowing it. Think CorningWare ‒ yes, those white baking dishes with the blue cornflowers that move seamlessly from the freezer to the oven without breaking. And if your kitchen contains some of these hand-me-downs, you’re in luck: CorningWare is the original freezer-refrigerator-stove-to-oven bakeware that survives all temperatures without breaking. Even the glass lids are oven-safe. After all, isn’t that the same material they originally used to fabricate missile nosecones? But how CorningWare evolved from missiles to grandma’s kitchen is another story.

The Evolution of CorningWare

The Corning Glass Works first introduced CorningWare, then known as Pyroceram, in 1958. The entire line consisted of a skillet, three saucepans and four covers, all also made of Pyroceram. It was touted as the only cookware that you could use for cooking, serving and storing in the refrigerator. It was an immediate hit with housewives, so much so that the company ran out of stock.

The Pyroceram lids were soon replaced with glass versions, also touted as fully capable of surviving temperature swings. However, the fate of CorningWare and all its products suffered setbacks through mergers and acquisitions, leaving the manufacturing of all CorningWare pieces questionable.

All this to say that unless you are positive that your CorningWare is Pyroceram and the wording on the bottom of your cookware states that it’s safe for stovetop-to-oven-to-freezer use, be very cautious. Cracking, breaking and exploding have been reported. The good news is that all the pieces are safe in the microwave and in oven temperatures up to 350 degrees Fahrenheit.

What About Those Glass Lids?

Just as the dishes from Corning Glass Works have undergone considerable transformation, so have the lids. The originals, made with Pyroceram, could withstand all the same heat fluctuations as the baking dishes themselves ‒ until technology and cost intervened. The glass lids used today are not as versatile, and they cannot tolerate sudden shifts in temperature.

CorningWare suggests heating the oven before putting a dish with a glass lid inside it and keep the heat at or below 350F. If you’re freezing a dish, cover it with foil, not the glass lid, before putting it into the freezer. When you’re ready to reheat the food, heat the oven and cover it with a room-temperature glass lid.

Buying CorningWare Today

In 2000, CorningWare discontinued the Pyroceram bakeware line, and instead, they began to focus on a lighter version made of three layers of glass. Touting it as a homemaker’s answer to light cookware, the resulting line is named “Simply Lite.” The product comes with glass lids for cooking and plastic lids for storage. The glass lids must be used only in a heated oven and cannot withstand swings in temperature.

CorningWare by Other Names

Building a better mousetrap is what eventually sunk the original CorningWare line. The bakeware was so resilient that it rarely had to be replaced, which meant its sales were limited to new users. The company tried to expand the line with new and different colors with limited success. The new owner of the company, World Kitchen, began to manufacture ceramic cookware that did not withstand the heat of the cooktop.

However, in 2008, a new line, Corelle, was launched for stovetop use. Produced in France, it originally utilized the technology of Pyroceram in the dishes and the lids. Today, the lids are made of glass, and users must adhere to the limitations of heating the oven before putting the dish inside. Temperature swings will cause the lid to break.

About the Author

Jann Seal

My seventh grade English teacher didn't realize what she was unleashing when she called me her "writer," but the word crept into my brain. I DID become a writer. Of advertising copy, dialogue and long-term story for several network soap operas, magazine articles and high-calorie contents for the cookbook: Cooking: It AIn't Rocket Science, a bestseller on Amazon! When I'm not writing, I'm cooking!