What Is the Difference Between PYREX and pyrex?Corning invented the brand Pyrex in 1915 and made all Pyrex products with borosilicate glass. This type of glass has an element called
boron trioxide in it, which makes it highly resistant to major temperature changes, reducing the risk of it breaking.
Historically, Corning owned the trademark to the PYREX and pyrex logos and they were used interchangeably on all Pyrex branded products. Corning later licensed the use of the names PYREX and pyrex to two different companies who now produce the glass cookware.
You’ll now find cooking products labeled PYREX in Europe, Africa, and the Middle East, where they are still made with borosilicate glass. The label pyrex stayed stateside, and in the rest of North America, South America, and Asia, and the company that makes them no longer uses borosilicate glass. Instead, they are made with tempered soda-lime glass, which is heated and cooled in a manner that makes it more durable than regular glass under temperature fluctuations. While it’s still heat-resistant, it’s not quite as heat-resistant as borosilicate glass.
PYREX vs. pyrex: Which Is Safer?
Since PYREX is made with borosilicate glass, it is more heat-resistant and therefore less prone to breaking due to any sudden changes of temperature such as transferring a casserole from the refrigerator directly to the oven. That makes PYREX cookware safer than pyrex cookware, which runs a higher risk of exploding due to thermal shock—when the glass goes through an extreme temperature change that can cause it to fracture.
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