A friend of mine reports a Pyrex pan cracked and broke inside her oven today. She was baking chicken breasts in it.
What happened? We've known for years that Pyrex is not supposed to be used on the stovetop or under a broiler. But in the oven seems to be what it's sold for, right? Riiiiiight. When it used to be made by Corning, Pyrex used to be made of borosilicate glass, which is able to tolerate wide temperature shocks, say, from freezer to preheated oven. But Corning sold that division to some other manufacturer, which can use the same brand name but switched materials to tempered soda glass (http://en.wikipedia.org/wiki/Pyrex).
Now, tempered soda glass is pretty OK with up-shock (cold pan put into a preheated oven), but not with down-shock (colder liquid into the hot dish, for example). What does that mean for you? It means that if you put the hot pan on something cold, for example, it may shatter... it also means that if you start a slab of meat in the dry pan, when the meat releases juices, the cooler juices will hit the hot dry pan and break it.
The manufacturer warns of that (in the usual teeny tiny type) that one needs to "put some liquid in the dish with the food before putting it in the oven" but to my mind, selling kitchenware with a brand name that has been trusted for 100 years (give or take) for thermal shock but making it with cheaper glass is cheating. They ought to put a big warning on the label, and then another one (with the "not for stovetop or broiler use") on the glass itself.
Not that I'm usually in favor of more government in the private lives of people, but I'm gonna side with the European contingent, where Pyrex is still made with borosilicate glass. I think they call it something exotic, what's it called in English, oh, yes!, "we don't like false advertising" or something like that.
I would like to ask people to file a complaint with the US Consumer Product Safety Commission (http://www.cpsc.gov/) when things like that happen. It's the only way to counteract the manufacturer's claim that the "new material is just as safe as the old one", which is clearly not true. Send the pictures too.
Now, just so I don't feel as cynical, I'd like to think that they changed to tempered soda glass for some reason that is not "it's cheaper and more common" -- glass is a weird wonderful thing, but one of the compromises one often gets with glass is that you can pick thermal-shock resistance or mechanical-shock resistance, not both... thus, you can get stuff like Visions Cookware (http://www.visions-cookware.com/) and Ceran stovetops (the glassy smooth-top ranges) that resist enormous thermal shocks but break with no provocation, to Pyrex (borosilicate) with resists large thermal shocks and is harder to break, to stuff like Corelle dishes that are terribly hard to break but don't resist thermal shocks well. Maybe they switched because people were complaining their old-standby Pyrex dishes were breaking too easily? I know that one can hardy find Visions pots and pans anymore because people found out the hard way that you could break them by just banging say, a spoon on the pot to avoid drips like one does with metal pots.
Either way, be careful with the stuff.
What happened? We've known for years that Pyrex is not supposed to be used on the stovetop or under a broiler. But in the oven seems to be what it's sold for, right? Riiiiiight. When it used to be made by Corning, Pyrex used to be made of borosilicate glass, which is able to tolerate wide temperature shocks, say, from freezer to preheated oven. But Corning sold that division to some other manufacturer, which can use the same brand name but switched materials to tempered soda glass (http://en.wikipedia.org/wiki/Pyrex).
Now, tempered soda glass is pretty OK with up-shock (cold pan put into a preheated oven), but not with down-shock (colder liquid into the hot dish, for example). What does that mean for you? It means that if you put the hot pan on something cold, for example, it may shatter... it also means that if you start a slab of meat in the dry pan, when the meat releases juices, the cooler juices will hit the hot dry pan and break it.
The manufacturer warns of that (in the usual teeny tiny type) that one needs to "put some liquid in the dish with the food before putting it in the oven" but to my mind, selling kitchenware with a brand name that has been trusted for 100 years (give or take) for thermal shock but making it with cheaper glass is cheating. They ought to put a big warning on the label, and then another one (with the "not for stovetop or broiler use") on the glass itself.
Not that I'm usually in favor of more government in the private lives of people, but I'm gonna side with the European contingent, where Pyrex is still made with borosilicate glass. I think they call it something exotic, what's it called in English, oh, yes!, "we don't like false advertising" or something like that.
I would like to ask people to file a complaint with the US Consumer Product Safety Commission (http://www.cpsc.gov/) when things like that happen. It's the only way to counteract the manufacturer's claim that the "new material is just as safe as the old one", which is clearly not true. Send the pictures too.
Now, just so I don't feel as cynical, I'd like to think that they changed to tempered soda glass for some reason that is not "it's cheaper and more common" -- glass is a weird wonderful thing, but one of the compromises one often gets with glass is that you can pick thermal-shock resistance or mechanical-shock resistance, not both... thus, you can get stuff like Visions Cookware (http://www.visions-cookware.com/) and Ceran stovetops (the glassy smooth-top ranges) that resist enormous thermal shocks but break with no provocation, to Pyrex (borosilicate) with resists large thermal shocks and is harder to break, to stuff like Corelle dishes that are terribly hard to break but don't resist thermal shocks well. Maybe they switched because people were complaining their old-standby Pyrex dishes were breaking too easily? I know that one can hardy find Visions pots and pans anymore because people found out the hard way that you could break them by just banging say, a spoon on the pot to avoid drips like one does with metal pots.
Either way, be careful with the stuff.
