How To Authenticate Vintage Pyrex

The moments after one learns that vintage Pyrex can cost thousands of dollars under certain conditions can inspire a roller coaster of emotions. The first feeling is an almost palpable regret, as memories of leftover broccoli, chop suey, and pot roast once haphazardly packed into these newly valuable vessels flash before one's eyes. The next is motivation; a drive to identify these classic Pyrex pieces at thrift stores, garage sales, and online, ideally for a serendipitous discount. But even then, you need to know if you're nabbing the real deal, or some kind of Pyrex dupe.

A fair amount of vintage Pyrex in the United States can be identified by the capital letters emblazoned on the bottom of the item. The multimedia culinary resource America's Test Kitchen even produced a short video to this effect, illustrating the difference between the shouty kitchenware of yore versus today's more whispered printed tones. Pyrex itself advises that aspiring treasure hunters consult with antique professionals to be sure, which becomes even more critical as those price tags tick up.

Pyrex products are made with either soda-lime or borosilicate glass. The latter is more durable and, as luddites might surmise, more likely to make up the older stuff. They really don't make the proverbial 'em like they used to. One of the main advantages of borosilicate glass over modern compositions is its ability to withstand drastic temperature changes that may cause other materials to crack or even shatter. That's why you can safely bake with Pyrex so long as you use the right type. (Note that the dishware's logo isn't a good indicator as to whether or not it's oven-safe.)

There are also, of course, aesthetic differences. Anyone in possession of a fair amount of Pyrex can probably open their cabinets to see through a collection of clear baking dishes, storage containers, and measuring cups. Even Pyrex's more colorful selections are largely translucent shades of blue, rouge, and green. So you aren't quite going to find a new edition that seems as striking as those old fashioned baby blue flowers on their creamy white canvas. But who knows; take care of your Pyrex, and one day it might just take care of you.