When New Yorker Bessie Littlejohn asked her husband Jesse if he thought the glass he was working on at Corning Glass works might work for baking, she could never have imagined the part she was playing in establishing one of the world’s most successful kitchenware brands.
Corning had developed a borosilicate glass that was able to withstand extreme heat and cold without breaking. They called it Nonex and marketed it for battery jars and lanterns, which tended to crack when they came into contact with rain or snow when they were hot. But its success also ended the need for replacement glass for those items and others like them.
Corning needed a new outlet for its heatproof glass and Bessie provided the answer. Jesse came home with a Nonex battery jar for her to test in the oven; the sponge cake turned out perfectly and the jar stayed intact. Not only that, but Bessie could see the food as it cooked. Corning realised she was on to something and the firm hired several women to join the research team tasked with testing the Pyrex brand.
Two years later, in 1915, the first set of 12 pieces of Pyrex was launched. Early products included the typical Pyrex casserole dishes as well as pie plates, shirred egg dishes, custard cups, loaf pans, oval baking dishes, cut-glass teapots and engraved dishes. Ten years later the liquid measuring cup was introduced with two spouts, one each on opposite sides to allow for left and right-handed pourers, and in the 1940s the red measurements were added.
Early Pyrex was produced using a semi-automated hand blowing process, making it expensive. Initially the company’s marketing was aimed at wealthy families; an early advertisement showed a maid using Pyrex rather than a housewife. And although one of its main features was its ability to go straight from the refrigerator to the oven, in the 1920s refrigerators were considered a luxury and only the upper echelons of society could afford to have their homes wired for electricity. This problem was solved when Corning dramatically cut the cost by developing fully automated machine pressing and by the early 1930s Pyrex was available at most department and hardware stores. It even aided in the war effort: Corning developed a line of durable military mess ware and during WWII emphasised the patriotism of the product with adverts that included lines such as, ‘My wife sure makes food fight for freedom!’
Pyrex lids are designed to double as trivets for the dishes they fit and the base of a dish will fit comfortably inside the inverted cover.
Pyrex also owed part of its success to its easy maintenance; it was far easier to scrub clean than the metal cookware that was commonly used. And then there was the added bonus of reduced energy use. Because the glass absorbs and conducts heat energy rather than reflecting it (as metal does), the cooking temperatures could be lowered.
In the 1940s the formula for Pyrex glass was changed from the original borosilicate glass to tempered soda lime glass, which was less expensive to manufacture and also had the advantage of increased impact resistance. This in turn led to the introduction in 1945 of a soda lime opal glass that could be painted in bright colours and Pyrex became a kitchen must-have. The first coloured line was a nesting bowl set, known today as the ‘primary colours’ set; new styles and patterns were introduced from the 1950s through to the 1970s. (All up, Pyrex has more than 150 patterns, 50 colours and 30 collections). “In the post-war period you have this explosion of colour in the kitchen, with plastics and other materials, and the mixing and matching of colours in tableware,” notes Juliet Kinchin, curator of modern design at the New York Museum of Modern Art. “That’s also when the barrier between the kitchen and other spaces broke down; the kitchen became a communal space. With new, spacious kitchen designs, dishes were on view for all to see. With coloured Pyrex came the oven-to-table idea, which had always existed but was adopted by wealthier households after the war.”
Today Pyrex is such an institution that the Corning Museum of Glass has established a pattern library for collectors to browse, helping people to enjoy the nostalgia of their childhood in their kitchen. Pyrex can also be dated from the embossed stamp on the bottom of every piece, which has had various design changes over the years.
You can still pick up a piece of vintage Pyrex for a few dollars at an op shop but there are some designs with universal appeal and they’ll cost you a bit more: a set of mixing bowls in the Dots pattern, for example, are regularly selling on eBay for more than $100. The opal glass colour ware and its decoratively patterned pieces dating from the 1950s and later are the most popular with collectors, particularly patterns such as the 1956 Pink Daisy and the 1957 Butterprint. The pattern that currently holds the title of most expensive is called Lucky in Love. A promotional item released in 1959, it has green shamrocks and pink hearts encircled by blades of green grass. In 2017, an original Lucky in Love casserole sold at auction in the USA for – wait for it – $5994. That’s about $5984 more than the average piece of vintage Pyrex.
Early Pyrex wasn’t made to withstand the rigours of a dishwasher and many pieces will show damage to the paint and loss to the glossy finish. “A shiny finish is the most important factor for most Pyrex collectors,” says US collector Nicole Miller (@pyrexnplants), “but I stay open-minded when repurposing flawed pieces. A few scratches are not a huge deal but if they lose the shine and are dull or chipped, I usually make them into a planter.”
If you’re thinking of buying your Pyrex to use rather than display, remember that any of the ovenware made prior to the 1940s is not microwave safe. You also really don’t want to put Pyrex decorated in gold leaf or other metallic paint in the microwave.
Clear and opal glass bakeware should only be used in a conventional oven or microwave and not on a stovetop burner; thermal shock can be sudden and explosive. You might now be wondering how it is that the cookware can go straight from the fridge to the oven without suffering said shock, and the simple answer is because the entire piece will be exposed simultaneously to the same heat, so the temperature will change evenly.
In 2002, Dianne Williams, aka The Pyrex Lady, decided to collect every piece of Pyrex offered in Corning retail catalogues from 1915 to 1983. By 2009 she had all but a handful of pieces. In 2010, her collection, including all the Pyrex ephemera she had amassed as well as her manuscript for an unpublished Pyrex collector guide book were acquired by the Corning Museum of Glass for its collection and archives.
The online resource The Pyrex Collector has tons of information for budding collectors and these are just a few of the tips:
