Are Your Pyrex Dishes Really Vintage? Here's How To Tell The Difference

Vintage Pyrex is a hot commodity these days, with some products easily going for hundreds of dollars online. After a lucky find at a flea market or garage sale, or maybe even a look through your closet, you might be wondering if a newfound Pyrex dish is considered vintage. Rather than asking around on social media, or rummaging through archival kitchen store catalogs, you can actually tell if a Pyrex dish is vintage purely based off of its appearance. The easiest way to find out? Flip the item over and check its logo. If the bottom of the dish says "PYREX" in sharp, capital letters, it's likely considered vintage. On the flip side (no pun intended), if your glass ovenware boasts a more rounded, lowercase "pyrex" logo, it's probably not vintage. But why is this the case? 

Well, some time in the late 1970s, the iconic glassware company shifted its iconic branding, debuting the lowercase logo still seen today. While not a definitive cut-off, it helps give collectors a better estimate of a dish's year of origin. Fair warning, if you're outside of the United States, you might want to take this advice with a grain of salt. In Africa, the Middle East, and Europe, Pyrex dishes are still branded with the all-caps "PYREX" logo, just as the vintage American dishes were back in the day. While they might appear as thought they were crafted in the mid-20th century, they could have just recently left store shelves.

Vintage Pyrex is so in demand not just because of its age or aesthetic. Believe it or not, when the all-caps "PYREX" logo went lowercase, the glassware's material changed with it. In the company's early years, Pyrex dishes were made with borosilicate glass, the same type of glass found in laboratory test tubes and beakers today. Borosilicate glass is treasured for its strength, since it can easily withstand extreme temperature shock without worry. The material is so strong, that old-timey recipe books used to frequently call for you to directly transfer Pyrex dishes from the freezer to the oven.

Now, though, your modern Pyrex needs to be at room temperature before being exposed to heat. Your oven also needs to have come all the way to temperature beforehand. In its American kitchenware products, Pyrex now uses soda lime glass, a material that, while still tempered and much stronger than standard glass, isn't nearly as strong as borosilicate. Soda glass has a tendency to expand when experiencing temperature shock, meaning that if you put modern Pyrex dishes in the broiler, you won't end up with a delicious meal on your table, but rather a dangerous, shattered mess.