PUBLIC SERVICE ANNOUNCEMENT

[frobzwiththingz]

Far too many people have had "Pyrex" pans and bowls explode on them in the past 6 months or so, so i feel like this deserves a general warning.

Pyrex brand pans are *NOT* made of what lab geeks think "Pyrex" is!
They are NOT borosilicate glass! Many years ago, they were. But they haven't been for at least 20 years now. They WILL sometimes explode on you if you use them directly over a gas flame, and you'll get showered with boiling water, glass, and (in my case ~10 years ago) sulfuric acid. DONT DO THAT! Buy some REAL borosilicate lab glassware or other cookware that specifically tells you that it's OK to use on the stovetop. All of the current "Pyrex" cookware does tell you not to do this, but usually only on the box it came in, and in small print. Useless.

I'm not much for government intrusion in commerce, but this seems to be one case where that brand name, which now has an impossible-to-get-rid-of association with certain technical properties (like not exploding due to thermal shock) should not be allowed to be used on glassware that cannot be used safely over a flame.

Be careful out there.

Comments

[rmd.livejournal.com]

yes. this is not the pyrex we're looking for.

[corivax.livejournal.com]

Huh! That explains the pyrex measuring cup I exploded once.

[solarbird]

I did not know this! This is good to know.

[quietann.livejournal.com]

I learned this the hard way about 10 years ago. Sigh.

[bikergeek.livejournal.com]

Thanks for the warning. As a former (albeit failed) chemistry major, I think of Pyrex in lab-geek terms as well. Bummer to know I can't count on kitchen Pyrex to do the things lab Pyrex does, but it's good I found out before I got hurt.

[sunspiral.livejournal.com]

Bastards. This ought to be considered fraud. "Gee, we'll take a trademark for thermal-shock resistant borosilicate glassware and use it to sell overpriced shit that shatters when it's used like the older stuff labeled the same way! Our profits will go way up and our stockholders will love us! Um, unless they're dealing with second-degree burns..."

[cutieperson]

some history shows that they did have a line of products actually meant for use on the stovetop, as opposed to the oven. i even had a few of those pans until a couple years ago...

[lemur-catta.livejournal.com]

Wow. That does seem like deceptive advertising. I'm not a fan of warning labels and law suits either but it would be nice if they made an effort to make sure folks know that.

Has Corningware changed too?

[ceo]

As I discovered the hard way.

[jcgbigler.livejournal.com]

Pyrex 7740 is the low-expansion borosilicate glass developed by Corning Inc. in 1924. Laboratory glassware is required to conform to ASTM standard E438-92(2001)e1: "Standard Specification for Glasses in Laboratory Apparatus". Consumer-grade Pyrex is not required to conform to this specification.

Corning Inc. sold its consumer division to World Kitchen (a division of Borden Foods) in 1998. Pyrex labware is still made by Corning, but consumer Pyrex is now made by World Kitchen. Certainly since the 1970s (when I was first aware of such things), Pyrex consumer glassware has had an explicit warning on the packaging or stamped into the glass that warns the consumer not to use it on the stovetop. If you need consumer glass that you can use on a stovetop and that has similar properties to Pyrex, you probably want Pyroceram, a sandwich made of a ceramic core with a thin layer of Pyrex on the outside and marketed as "Corning Ware". Corning Ware products are advertised as "freezer to stovetop".

However, since the 1998 sale, there has been an increase in complaints about consumer grade Pyrex cracking due to thermal stress, especially stresses associated with rapidly cooling the glass. Corning and Borden/World Kitchen spokespeople maintain that consumer-grade Pyrex has never been considered appropriate for stovetop use, in part because repeated mechanical shocks, scratches, etc. that happen through normal cookware use can introduce stresses in the glass that make it more prone to breakage due to uneven expansion. However, as far as I know, rapid cooling (such as pouring cold water into a hot Pyrex dish) is not inconsistent with the product directions, but should probably be considered unsafe.

One of the reasons Corning sold its consumer division is because they've never done well at managing high-volume, low-margin manufacturing. One of the compromises that usually accompanies high-volume, low-margin manufacturing is not putting more expense into quality than the market will actually pay for. My guess is that World Kitchen Pyrex is a little more uneven, and that the unevenness makes thermal expansion cause stresses in random directions, resulting in much more frequent breakage.

However, while I agree that there's a problem with the glass not meeting what I think are mostly reasonable expectations, the libertarian in me still disagrees with the statement:

I'm not much for government intrusion in commerce, but this seems to be one case where that brand name, which now has an impossible-to-get-rid-of association with certain technical properties (like not exploding due to thermal shock) should not be allowed to be used on glassware that cannot be used safely over a flame.

on the grounds that even if this has been possible until recently, it's still a case of using the product in a manner inconsistent with the labeling that has appeared consistently on the products for at least 30-40 years, and should therefore be considered to be at the consumer's own risk.

P.S. After a couple of second thoughts and noticing typos, I finally gave in and checked the "spell-check and preview" box. Among its suggestions were "brisket" for "borosilicate" and "Proscenium" for "Pyroceram".

[sunspiral.livejournal.com]

Interesting article, but it backs up the view that Pyrex was trademarked as a thermal shock-resistant and durable (borosilicate) glass. What the company has done is effectively bait & switch, since they're now selling non-boro and thus less durable glass under the Pyrex name.

[sunspiral.livejournal.com]

It's not even a question of stovetop use, though. The Pyrex breakage I've experienced in the last few years has never been from stovetop use, just from routine kitchen handling and trips in & out of the oven. The most dramatic involved a large Pyrex pan full of food (including a fair bit of liquid) being removed from a very hot oven and spontaneously shattering. This isn't a matter of Those Wacky Consumers or hair-splitting over proper or improper use, it's a matter of a company replacing the specific material and/or process that was used to make a specific product with something of substantially lower quality while keeping the trademarked name associated with the higher quality item. Voting with one's feet and wallet is insufficient in a case like this; it's exactly where government is needed to protect the citizen.

[jcgbigler.livejournal.com]

True, and I did mention that in my overly long post (end of 3rd paragraph). I agree that if the product fails in an unsafe manner when used according to the directions (such as the rapid-cooling failures that you describe and that have been reported recently), that there's a problem and that our government should step in and do something.

In re-reading my post, I realize that its tone is somewhat inconsistent with the overall viewpoint I was trying to convey, which is that yes, there's a quality problem that seems to stem from (or have gotten worse) when Corning sold its consumer division. That is unacceptable and needs to be addressed. However, new quality problems notwithstanding, it should never have been considered "safe" to use consumer grade Pyrex (as opposed to lab grade Pyrex, which meets ASTM E 438) over an open flame.

[sunspiral.livejournal.com]

I think we're in complete agreement. Now to find out if the labware supply places sell roasting pans.

[marmota.livejournal.com]

ruhroh. WoWFtVoE?

[frobzwiththingz.livejournal.com]

I'm pretty much in broad agreement with you; but what continues to nag me is that i pretty clearly remember (as much as one can "clearly" remember things from 3 decades ago) seeing TV commercials for Corning Pyrex consumer cookware in which the product *was* shown in use over the stovetop flame, quickly quenched in cold water, etc. This was the very factor on which they were pitching the product. I wonder how i could find out if such commercials actually existed, or whether i'm constructing memories. Does the national TV archive down in DC have a commercial archive as well?

[starphire.livejournal.com]

No, you're definitely correct that it existed, and was marketed like that. I'm not sure about the commercials, but They had all-glass cookware that looked exactly like regular metal cooking pots & pans, with long handles, glass lids to go with them, and everything, and catalog photos and such showed them on the stovetop. They were made of colored transparent glass. And I don't think it's even been more than maybe 15 years since I've seen them in stores.

[drwex]

Holy crap. Thanks for the PSA. I have done this from time to time (cooked Pyrex over open flame) and never had any idea it was risky.

[perspicuity.livejournal.com]

funny, i just posted this: http://www.livejournal.com/users/perspicuity/446840.html
the other day, and now i see a couple references to pyrex and exploding in LJ and blogs. huh.

i have "corning visions" which is supposedly rated stovetop, and hasn't had issues in the years i've owned it. i also have "corning ovenware" which is very much not for stovetop and has tons of warning about thermal shock - like not putting it on metal surfaces especially when very hot or very cold.

googling for it a bit seems to reveal that it's not very much for sale now, and that people are collecting it. i have both amber and amethst/rose colored stuff. the salad bowls are especially choice :)

#

ok

[cthulhia]

so before I go nuts and spend $100 on eBay to instantly own a 17-pc set of amber corning ware... is there anything else in the glass that makes it not as ok to cook with?

[vashti.livejournal.com]

My mum did this in around ... 1984? 85? Casserole dish out of the oven, over the gas flame, stepped out of the kitchen, BANG.

It was very loud, very, very loud. And there were a lot of very, very tiny pieces.

I have a Pyrex casserole dish, but I've never put it on the stove, and (so far) it hasn't blown
up.