http://afarmerinohio.blogspot.com/2011/04/how-reformulating-pyrex-made-crack.html
Borosilicate Was what I was trying to remember. They still use that formula in Europe from what I remember.

Cynthia linked to this on facebook, I thought it was interesting:



BTW - my pyrex quart measuring cup recently broke when a mug fell on it. I am using now a silicon quart measuring cup, which I had rarely used prior to this.

Regards,

Corning Ware isn't Pyrex and doesn't advertise itself as such, but I thought of this thread (and ironically, forgot all the caveats I posted on page 1), when I cracked up my mother's ( ) 9 x 13 Corning Ware casserole dish the other day. Sad because it was my mother's. Sad because it was 9 x 13, which is a very useful and not-so-easy-to-find size.

What I did was put some beef ribs in the dish and roast them in a very hot oven for a half hour or so. Then I took the dish out of the oven, en route to covering the ribs with foil and turning the oven down to roast them at a longer temperature for a while, put the dish down on the stovetop on top of a burner ... whaddyacallem? Burner guard? The star-shaped thing that your pan sits on above the burner... anyway.

I took the intensely hot Corning Ware glass casserole dish out of the oven, put it on the cold burner guard, decided I should add some liquid to the bottom of the dish, poured in some cold water, and POW! The dish cracked in a star-shaped pattern into a half a dozen or so big pieces, mostly in lines coinciding with the arms on the burner guard. It was rather impressive that it fractured into such large pieces. It was also rather impressive how long it took the glass fragments to cool off enough to be safe to handle and throw out.

I miss that casserole dish. It was big and shallow, creamy white like milk, with red decorations on the side, including a red bird that reminded me of the Piasa bird, near where my mom was from.

Hi,

I saw this NBC 5 Chicago report on Pyrex: https://www.nbcdfw.com/news/local/Pyrex ... 17881.html

At 2:20, they show two baking dishes side by side. The dish on the left has a green tinge (made of soda lime glass) and the one on the right is clear (made of borosilicate). Both were filled with sand and heated to 450 degrees for an extended period of time. When removed from the oven, they were placed on a wet tile. The green tinged glass exploded due to thermal shock. The white glass under the same conditions cracked.

At home, I always place a towel or potholder underneath glass cookware exiting the oven. I never heat glass cookware to 450 degrees, I go up to 375 degrees or switch to a metal dish.

I have had Visionware as cooking pots, which are made with a low expansion glass. It can break, though it cracked rather than exploded.

It's good to finally know what to look for in the type of glass.

Regards,
Cathy2

Interesting article over on Gizmodo.

Within the article there's a reference to being able to buy borosilicate products from Amazon Basics for cheaper than the domestic lime-soda Pyrex product. However when I read through the reviews there were many reports of shattering and people disputing that it's actually borosilicate. In any case I found that OXO, a company in which I do have some trust, has a line of products they claim IS made of borosilicate and even advertise it as being freezer-to-oven safe (though I still don't think I'd do that).

"What does seem crystal clear on a scientific level is that borosilicate glass is less prone to thermal shock that soda lime glass. It’s also not hard to find, especially if you can live without the Pyrex logo being stamped on the bottom of your pan. Heck, Amazon Basics sells a pair of borosilicate glass pans for $15. The equivalent Pyrex-branded set made of tempered soda-lime glass costs $22. And according to experts, the Pyrex glass can explode into small pieces. Uncommon as these explosions may be, they sound bad."

Hi,

You may want to look at the video clip in my post just above yours for a 'as seen on tv' demonstration of how one glass cracks and the other breaks into small pieces. Once you have seen it, you will avoid the green hued soda lime glass for baking dishes.

Regards,
Cathy2

All of our Pyrex is pre-nuptual so it dates back to the late 1970s.

We have been quietly acquiring the old Pyrex dishes and the like from estates and from relatives who are closing down their kitchens. Those I know have had these pyrex containers for 30-40 years minimum.

jlawrence01 wrote:All of our Pyrex is pre-nuptual so it dates back to the late 1970s.

We have been quietly acquiring the old Pyrex dishes and the like from estates and from relatives who are closing down their kitchens. Those I know have had these pyrex containers for 30-40 years minimum.

It's still glass and it can break.

I used for many years clear vision pots, which use a low-expansion glass. They would occasionally break, too. The most vulnerable location was the handle.

Regards,
Cathy2