Photo by Jennifer Causey / Food Styling by Chelsea Zimmer / Prop Styling by Claire Spollen
In 1908, Corning Glass Works, in Corning, New York, developed a borosilicate glass that could withstand extreme heat and cold without breaking. They called the glass "Nonex" and used it in battery jars and railroad lanterns. Ironically, Nonex's strength meant battery jars and lanterns no longer broke and needed replacing, so the company looked for other ways to use its heatproof glass. In 1913, a woman named Bessie Littleton, who was married to Corning scientist Jesse Littleton, found it. After an earthenware baking dish cracked in her hot oven, Bessie asked Jesse to bring home a Nonex battery jar for her to experiment with. The sponge cake Bessie baked in the jar turned out perfectly, and the jar stayed intact. This sent Corning down a new path: cookware. In 1915, the company launched its first Pyrex line (Pyrex combined "pie" and "Nonex") with 12 pieces, including pie plates and a loaf pan. The 8-ounce liquid measuring cup came out 10 years later; early versions had a closed, D-shaped handle and tick marks made out of molded glass. (The red measurements were added in the 1940s.) In 1983, a redesign gave the cups an open handle, allowing for different-sized cups to be stacked and yielding the model that today is a staple of kitchens everywhere.
There's a whole community of Pyrex collectors out there scouring antique stores and estate sales for vintage editions of Pyrex cookware. Prices for some of the more coveted items—like those with special patterns or hard-to-find prototypes—can climb into the hundreds, sometimes even thousands, of dollars. One Pyrex piece from 1959 with the "Lucky in Love" pattern, a combination of hearts and clovers, sold for more than $4,000 in 2015. For some collectors, a draw to older Pyrex pieces is that they're made entirely of borosilicate glass, whereas modern Pyrex glassware can also be made of tempered soda lime glass. The brand switched its glassware formula in the 1950s, but has recently reintroduced borosilicate glass into some of its products, such as the Pyrex MealBox™ and Pyrex Hydration line. Both kinds of glass are heat-resistant and odor-resistant, but borosilicate glass can perform better than tempered soda lime glass when exposed to thermal shock—translating, for some collectors, into greater value.
By the Numbers
Pieces of Pyrex cookware sold in the U.S. by 1919
Original price of an 8-oz. measuring cup
Minutes it takes Pyrex cookware to go from being molded to ready for shipping (measuring cups take longer due to the process of adding tick marks)
Number of spouts on the first Pyrex measuring cup, to allow for left- and right-handed pours
Percent of U.S. homes that own Pyrex today