Equipment
Vintage Pyrex is a hot collector’s item, both for looks and functionality. Here’s how to tell if your recent thrift store score is actually vintage—and why it matters.
By
Published May 8, 2024.
Why does everyone love vintage Pyrex so much? The often brightly decorated glass containers have been causing a stir on social media lately, with home cooks and vintage cookware aficionados hunting them down in thrift stores and estate sales.
But it’s not just their aesthetic that makes them worth seeking out.
All Pyrex is made of tempered glass, which is engineered to be tougher than regular glass. If it breaks, it’s also designed to shatter into tiny, less-dangerous pieces, like a car windshield.
But vintage Pyrex is actually made out of an even stronger type of glass, and this difference has some key implications for use, care, and even safety.
Sign up for the Notes from the Test Kitchen newsletter
Our favorite tips and recipes, enjoyed by 2 million+ subscribers!
America's Test Kitchen will not sell, rent, or disclose your email address to third parties unless otherwise notified. Your email address is required to identify you for free access to content on the site. You will also receive free newsletters and notification of America's Test Kitchen specials.
The Type of Tempered Glass Matters
Recently I made a video on the difference between two types of tempered glass: soda lime and borosilicate. Pyrex used to be made out of borosilicate, but now it’s made of soda lime glass.
Soda lime is less tough than borosilicate, although it is tough on impact. (But I think we all know not to hit glass superhard.)
Borosilicate is what they use in laboratory glass and is tougher under any sudden temperature changes. You can’t take the new Pyrex dishes directly from freezer to oven anymore. You see that a lot in old recipes.
Now you have to bring the frozen dish to at least refrigerator temperature and fully preheat the oven first before putting the dish in. That’s because the high temperature fluctuations as an oven preheats can stress and shatter soda lime glass.
You can’t take the new Pyrex dishes directly from freezer to oven anymore.
So vintage Pyrex, made of borosilicate? It’s a big deal. It’s lasted for decades. (It’s not just vintage products that are made out of borosilicate, though—OXO, the manufacturer of our favorite reusable glass storage containers, makes its tempered glass out of borosilicate.)
Article
Why We Whack Our Skillets on Concrete
In the Test Kitchen, we have a go-to method for simulating years of use in your home kitchen.
Learn More
How to Tell Old vs. New Pyrex
Is your recent vintage store score made out of this material? I contacted Pyrex to ask if there’s an easy way to tell what material your Pyrex dish is made from, and the company had a simple answer: Look at the logo.
If it’s all caps “PYREX,” it’s vintage, made of borosilicate. If it’s lower case “pyrex,” it’s new, and it’s soda lime. (In Europe, Pyrex is still made of borosilicate. So these recommendations only apply to Pyrex in the United States.)
Remember, even if you have borosilicate Pyrex, you still have to be careful; it IS glass. But if you want to know what you’ve got, just check the logo.
How to tell if your Pyrex is new or vintage and why it’s important.
