Almost every garage sale has it. Our mother’s mother used it. And you rarely have to replace it unless Aunt Betty took yours home after the reunion picnic. Since the introduction of Pyrex in 1915, the glassware has baked, served, transported and stored its way into an estimated 80-percent of U.S. homes.

The Pyrex legacy began with a gift. A researcher at Corning Glass, Dr. Jesse T. Littleton, gave his wife a custom-cut casserole. The casserole was made from Nonex, a low-expansion glass intended to reduce breakage. Though a sturdy glass, Nonex contained lead, which made it unsuitable for cooking. Corning revised the formula to make a product from a lead-free tempered soda lime glass composite. The circular 9-inch pie plate was the first Pyrex piece to hit the market.

The clear, heat-resistant glass ovenware was an instant success, simplifying mealtime preparation and cleanup. The ability of Pyrex to withstand sudden changes in temperature put an end to the laborious process of using multiple pieces to bake, serve and store food. The American public embraced the product that promised to do more and do it better. Four years after introducing Pyrex, Corning sold over 4.5 million pieces.

Pyrex remains a staple in American kitchens, continually adapting to the consumer’s evolving needs. In 1930, Corning manufactured its Range Top Ware from Pyrex. Four years later, the company introduced a line of clear Flameware¬¬–stovetop pressed-glass cookware that included saucepans and skillets. By 1938, double boilers, teakettles and coffee percolators were added to the line, which Corning produced until 1979.

In 1948, the company began redesigning its Pyrex Ovenware and Flameware to create pieces in new sizes and colors. This effort launched the Pyroceram line¬–a white, ceramic-like material that could withstand even greater changes in temperature. The line also featured a decoration that became the product’s trademark: a small, blue cornflower.

From 1965 to 1970, Corning released a number of Pyrex pieces enhancing the product’s form and function. The up-scale Terra line looked dignified on dinning tables, and the Store ‘N’ See ware resolved the “what’s-in-there?” mystery of previously opaque containers. The company also designed the first smooth glass surface electric range made from Pyroceram and the wildly popular break-resistant dinnerware, Corelle Livingware.

As far as collecting goes, vintage Pyrex stays in fashion because it’s durable and affordable. Regardless of its age, a piece should withstand regular kitchen wear and tear as long as it is not chipped, cracked or scratched. Collectors favor pink and primary colors, but there aren’t any hard and fast rules to determine the worth of Pyrex. Collectors do tend to prize complete sets (original package is an added bonus), but a majority of individual pieces can be purchased for under $20.

Caring for Pyrex:

Pyrex is a durable glass suitable for use in the oven, microwave, freezer and dishwasher. But there are a few steps to follow to ensure the lifespan of your piece:

• Never use on stove-top burner, under broiler, or in a toaster oven
• Avoid serious changes in hot and cold temperatures (i.e. immersing a hot dish in cold water)
• Always add a fraction of liquid before baking foods that release liquids while cooking
• Don’t use or repair a piece if it is chipped, cracked or scratched