4 ms·

The Pyrex Glass Controversy That Just Won't Die (2019)

28 points by Tomte 2y ago

bmelton 2y ago
I went through this recently as I was buying housewares for my soon-to-be-moving-out daughter, and I was shocked to learn there's a pretty easy hack to knowing which Pyrex is which (at least for modern versions) -- The good borosilicate glass is branded with uppercase "pyrex" -- The potentially bad soda glass is branded with lowercase "pyrex" There are other clues too, like that the borosilicate ones aren't typically sold in the US, ergo typically aren't marked with imperial units, but if you're on the prowl for one or the other, upper/lower case is the surest giveaway (unless there are some counterfeits I have not knowingly encountered)
- adrian_b 2y ago
  Borosilicate glass is also very noticeably lighter than normal soda-lime glass. After you have handled both kinds of glass it is difficult to confuse them, especially in bigger vessels. Besides the fact that borosilicate glass has a lower density, the vessels made of borosilicate glass are made typically with thinner walls than those made of normal glass, which makes even greater the weight difference.
  - bmelton 2y ago
    Yeah if you're holding them in your hands they're very clearly different in weight and also color I just wasn't savvy to this knowledge when I was shopping for them on the internet until I dove deeper
- jdyer9 2y ago
  For what it's worth, the article says the exact opposite Protip: Look for all-caps PYREX graphics which can either indicate that is vintage or that it’s from Europe, where a company called Arc International owns the Pyrex brand and still makes its cookware out of borosilicate.
  - bmelton 2y ago
    I was just editing (thought it funny after I typed it and went downstairs to look) Thanks for the correction!
- deleted 2y ago
  [deleted]
- jpk2f2 2y ago
  You have it flipped. The "good" versions are in all caps, the newer models are lowercase. I have some old, borosilicate pyrex and the name is capitalized. If you look up a new pyrex measuring cup, you'll note that the name is lowercase.
  - bmelton 2y ago
    Yep! Edited. Thanks
philips 2y ago
It is absolutely annoying how difficult it is to find durable glassware. We use glassware for meal prep and freezing leftovers and the modern designs are constantly chipping away at the corners due to poorly designed radiuses. And worse the manufacturers, in particular Pyrex, makes it difficult to buy replacement parts. For example, they used to provide these excellent "Ultra" lids for their products to replace the terrible plastic lids that constantly break and crack. But, they have slowly been phasing them out and only have a few sizes remaining: https://corelle.com/products/pyrex-r-ultimate-white-lid-for-3-cup-glass-food-storage/?variant=51970940436851 https://corelle.com/products/pyrex-r-ultimate-white-lid-for-... We have stainless steel containers that we use too but those are obviously more annoying because they can't be microwaved at an office/school/etc. It is really a head scratcher that it is so hard to find quality food storage in 2025.
- cantrecallmypwd 2y ago
  The biggest problem is finding ergonomically low-effort, efficient storage glassware usable by elderly and disabled people. I wished OXO went away from plastic entirely.
  - nunez 2y ago
    I was surprised to learn that OXO doesn't carry plastic Good Grips containers anymore. This must have been another COVID special, as I purchased an entire set of them years ago. I had to purchase them on eBay. I like their glass containers but prefer not having to worry about them shattering.
- lenerdenator 2y ago
  > It is really a head scratcher that it is so hard to find quality food storage in 2025. Anything that seems basic that we cannot master in <current year>, especially if we already mastered it, can usually be explained by a desire to increase profit margin.
  - philips 2y ago
    Yeah, I understand that sentiment. But, usually some luxury company emerges charging 5x that provides the old product that actually worked.
kayfox 2y ago
This is ancedata, but the article says all pyrex cookware made after 1998 used soda-lime glass, but I do have an amount of pyrex cookware that appears to be made of borosilicate that I purchased between 2005 and 2013ish. I base this on the older pyrex having a clear and un-colored consistency that matches my Corning PYREX labware (also used in the kitchen) and the newer stuff having a green tint to it that matches other soda-lime glass. Personally I suspect that they phased out borosilicate glass in pyrex cookware between 2006 and 2009 and the lag in my ancedata is from slow stock turnover at the local supermarket. This would line up with the exploding glass incidents cited in the article. What may be a more plausible explanation to the exploding pyrex mystery is the proliferation of marble and other cut rock countertops. These countertops have a very high thermal mass and placing a just out of the oven casserole dish on them, even if completely empty, will most likely cause it to shatter from the rapid cooling of the base. So, as a kitchen safety tip, don't put hot glassware directly on countertops, use a trivet, dry kitchen towel or potholder.
- cgannett 2y ago
  This is good advice even if you are using a steel or cast iron bowl and a cheaper countertop because replacing countertop is expensive even with cheap materials.
- cantrecallmypwd 2y ago
  Thermal stress wears most objects. It's hit or miss but the loss of trust and goodwill occurred and hasn't been reversed. It's safer to not buy their new stuff so to not reward them for resting on their brand laurels. There are plenty of old and other borosilicate products to avoid them.
anenefan 2y ago
I have two unused still in their box pyrex baking trays that have been idle on hearing another exploding tray incident which occurred within my immediate neighbourhood. The article gives me some hope, I'll have to check if I've got proper pryex or expensive clear serving trays.
lenerdenator 2y ago
Well, yeah. That's what happens when you sell your product's reputation to fund bonuses and shareholder returns.
e40 2y ago
I've been buying OG Corning Ware from ebay for a while. There are good deals to be had and there are some insane prices for this old stuff, too. I'm talking the original borosilicate ones. Love them, though the handles can be fragile if you hit them in the wrong way. They are the perfect containers to heat up food in the microwave.
prpl 2y ago
I have a fond memory from ~1997 when my mom had a casserole dish in a hot oven she forgot about. For some reason, she decided she needed to cool it down quickly with a glass of water, and we were treated an impressive display of shattering pyrex.
- aaronbaugher 2y ago
  One time I had a Pyrex casserole dish in the oven under a pie to catch any overflow. When the pie was done, I was in the middle of washing dishes, so I pulled the casserole dish out of the oven and dropped it straight in the dish water. Boom.
beej71 2y ago
We had an explosion about 3 years ago. It was our fault (hot dish touching cold steel sink rim), but it still caught me by surprise. I'd known since I was a kid in the 70s that Pyrex was highly tolerant of heat changes, so I felt that shouldn't have happened. (And so violently! Glass went everywhere. All the food was out and prepped for dinner and it all went in the bin and we ordered takeout.) That's when we dug into it. Now we have a bunch of PYREX that we've picked up up second-hand. And we don't let it touch the sink after the oven. :)
- jandrese 2y ago
  I managed to explode a 9x13 by placing the cooled dish on the stovetop to free up counter space. This wasn't initially a problem, the problem came when I turned on what I thought was the front burner to start cooking, but was actually the burner the 9x13 was straddling. The explosion was interesting, it didn't make a "bang" but rather a "pop" sound and the shattered glass flew all over the kitchen. It probably would have been worse, but the 9x13 was full of brownie that probably absorbed some of the kinetic energy. It makes me wonder how glass cooktops avoid this problem. They have enormous uneven heating stresses every time they are used, and somehow manage to avoid flying apart.
throw0101b 2y ago
AIUI, products with "PYREX" (all-upper) is the old/original product, and "pyrex" (all-lower) is the new stuff: * https://www.allrecipes.com/article/what-is-the-difference-between-two-pyrex-types/ https://www.allrecipes.com/article/what-is-the-difference-be...
- deleted 2y ago
  [deleted]
throw0101b 2y ago
There are other companies that sell borosilicate glass products: * https://www.duralexusa.com/collections/duralex-bakeware https://www.duralexusa.com/collections/duralex-bakeware * https://old.reddit.com/r/BuyItForLife/comments/4gxf5w/found_a_few_sources_of_borosilicate_glass_cookware/ https://old.reddit.com/r/BuyItForLife/comments/4gxf5w/found_...
rini17 2y ago
Im in Europe where ISO standard borosilicate glassware is common. However it is softer and more easily scratched by sand grains than soda-lime glass. Sand can get into food from vegetables or herbs. I had such scratched borosilicate tea kettle which shattered completely shortly afterwards. So this might be the core issue and now I take the disclaimers "never use if scratched" seriously. Lab reagents are much less likely to contain sand grains so it won't happen there.
infinet 2y ago
Thanks for the link! I didn't know they were using soda-lime glass and still call it Pyrex. In the meantime, the Pyrex labware remains real: I routinely pour liquid nitrogen into room-temperature Pyrex beakers without issue. That is a sudden temperature change of 220°C or 400°F.
cantrecallmypwd 2y ago
Everybody knows Pyrex started cheaping-out on use of borosilicate glass about the time they changed the logo on measuring cups. "Pyrex" "glass" is mostly ordinary glass now and pure garbage because of the corrosive effects of long-term corporate enshitification.
Aloisius 2y ago
I just hate that the modern Pyrex measuring cup markings wear off in dishwashers. I have new Pyrex measuring cups that are unreadable after a couple years while 40 year old ones that look brand new.

28 points by Tomte 2y ago

I went through this recently as I was buying housewares for my soon-to-be-moving-out daughter, and I was shocked to learn there's a pretty easy hack to knowing which Pyrex is which (at least for modern versions) -- The good borosilicate glass is branded with uppercase "pyrex" -- The potentially bad soda glass is branded with lowercase "pyrex" There are other clues too, like that the borosilicate ones aren't typically sold in the US, ergo typically aren't marked with imperial units, but if you're on the prowl for one or the other, upper/lower case is the surest giveaway (unless there are some counterfeits I have not knowingly encountered)

adrian_b 2y ago
Borosilicate glass is also very noticeably lighter than normal soda-lime glass. After you have handled both kinds of glass it is difficult to confuse them, especially in bigger vessels. Besides the fact that borosilicate glass has a lower density, the vessels made of borosilicate glass are made typically with thinner walls than those made of normal glass, which makes even greater the weight difference.
- bmelton 2y ago
  Yeah if you're holding them in your hands they're very clearly different in weight and also color I just wasn't savvy to this knowledge when I was shopping for them on the internet until I dove deeper
jdyer9 2y ago
For what it's worth, the article says the exact opposite Protip: Look for all-caps PYREX graphics which can either indicate that is vintage or that it’s from Europe, where a company called Arc International owns the Pyrex brand and still makes its cookware out of borosilicate.
- bmelton 2y ago
  I was just editing (thought it funny after I typed it and went downstairs to look) Thanks for the correction!
deleted 2y ago
[deleted]
jpk2f2 2y ago
You have it flipped. The "good" versions are in all caps, the newer models are lowercase. I have some old, borosilicate pyrex and the name is capitalized. If you look up a new pyrex measuring cup, you'll note that the name is lowercase.
- bmelton 2y ago
  Yep! Edited. Thanks

philips 2y ago

It is absolutely annoying how difficult it is to find durable glassware. We use glassware for meal prep and freezing leftovers and the modern designs are constantly chipping away at the corners due to poorly designed radiuses. And worse the manufacturers, in particular Pyrex, makes it difficult to buy replacement parts. For example, they used to provide these excellent "Ultra" lids for their products to replace the terrible plastic lids that constantly break and crack. But, they have slowly been phasing them out and only have a few sizes remaining: https://corelle.com/products/pyrex-r-ultimate-white-lid-for-3-cup-glass-food-storage/?variant=51970940436851 https://corelle.com/products/pyrex-r-ultimate-white-lid-for-... We have stainless steel containers that we use too but those are obviously more annoying because they can't be microwaved at an office/school/etc. It is really a head scratcher that it is so hard to find quality food storage in 2025.

cantrecallmypwd 2y ago
The biggest problem is finding ergonomically low-effort, efficient storage glassware usable by elderly and disabled people. I wished OXO went away from plastic entirely.
- nunez 2y ago
  I was surprised to learn that OXO doesn't carry plastic Good Grips containers anymore. This must have been another COVID special, as I purchased an entire set of them years ago. I had to purchase them on eBay. I like their glass containers but prefer not having to worry about them shattering.
lenerdenator 2y ago
> It is really a head scratcher that it is so hard to find quality food storage in 2025. Anything that seems basic that we cannot master in <current year>, especially if we already mastered it, can usually be explained by a desire to increase profit margin.
- philips 2y ago
  Yeah, I understand that sentiment. But, usually some luxury company emerges charging 5x that provides the old product that actually worked.

kayfox 2y ago

This is ancedata, but the article says all pyrex cookware made after 1998 used soda-lime glass, but I do have an amount of pyrex cookware that appears to be made of borosilicate that I purchased between 2005 and 2013ish. I base this on the older pyrex having a clear and un-colored consistency that matches my Corning PYREX labware (also used in the kitchen) and the newer stuff having a green tint to it that matches other soda-lime glass. Personally I suspect that they phased out borosilicate glass in pyrex cookware between 2006 and 2009 and the lag in my ancedata is from slow stock turnover at the local supermarket. This would line up with the exploding glass incidents cited in the article. What may be a more plausible explanation to the exploding pyrex mystery is the proliferation of marble and other cut rock countertops. These countertops have a very high thermal mass and placing a just out of the oven casserole dish on them, even if completely empty, will most likely cause it to shatter from the rapid cooling of the base. So, as a kitchen safety tip, don't put hot glassware directly on countertops, use a trivet, dry kitchen towel or potholder.

cgannett 2y ago
This is good advice even if you are using a steel or cast iron bowl and a cheaper countertop because replacing countertop is expensive even with cheap materials.
cantrecallmypwd 2y ago
Thermal stress wears most objects. It's hit or miss but the loss of trust and goodwill occurred and hasn't been reversed. It's safer to not buy their new stuff so to not reward them for resting on their brand laurels. There are plenty of old and other borosilicate products to avoid them.

anenefan 2y ago

I have two unused still in their box pyrex baking trays that have been idle on hearing another exploding tray incident which occurred within my immediate neighbourhood. The article gives me some hope, I'll have to check if I've got proper pryex or expensive clear serving trays.

lenerdenator 2y ago

Well, yeah. That's what happens when you sell your product's reputation to fund bonuses and shareholder returns.

e40 2y ago

I've been buying OG Corning Ware from ebay for a while. There are good deals to be had and there are some insane prices for this old stuff, too. I'm talking the original borosilicate ones. Love them, though the handles can be fragile if you hit them in the wrong way. They are the perfect containers to heat up food in the microwave.

prpl 2y ago

I have a fond memory from ~1997 when my mom had a casserole dish in a hot oven she forgot about. For some reason, she decided she needed to cool it down quickly with a glass of water, and we were treated an impressive display of shattering pyrex.

aaronbaugher 2y ago
One time I had a Pyrex casserole dish in the oven under a pie to catch any overflow. When the pie was done, I was in the middle of washing dishes, so I pulled the casserole dish out of the oven and dropped it straight in the dish water. Boom.

beej71 2y ago

We had an explosion about 3 years ago. It was our fault (hot dish touching cold steel sink rim), but it still caught me by surprise. I'd known since I was a kid in the 70s that Pyrex was highly tolerant of heat changes, so I felt that shouldn't have happened. (And so violently! Glass went everywhere. All the food was out and prepped for dinner and it all went in the bin and we ordered takeout.) That's when we dug into it. Now we have a bunch of PYREX that we've picked up up second-hand. And we don't let it touch the sink after the oven. :)

jandrese 2y ago
I managed to explode a 9x13 by placing the cooled dish on the stovetop to free up counter space. This wasn't initially a problem, the problem came when I turned on what I thought was the front burner to start cooking, but was actually the burner the 9x13 was straddling. The explosion was interesting, it didn't make a "bang" but rather a "pop" sound and the shattered glass flew all over the kitchen. It probably would have been worse, but the 9x13 was full of brownie that probably absorbed some of the kinetic energy. It makes me wonder how glass cooktops avoid this problem. They have enormous uneven heating stresses every time they are used, and somehow manage to avoid flying apart.

throw0101b 2y ago

AIUI, products with "PYREX" (all-upper) is the old/original product, and "pyrex" (all-lower) is the new stuff: * https://www.allrecipes.com/article/what-is-the-difference-between-two-pyrex-types/ https://www.allrecipes.com/article/what-is-the-difference-be...

deleted 2y ago
[deleted]

throw0101b 2y ago

There are other companies that sell borosilicate glass products: * https://www.duralexusa.com/collections/duralex-bakeware https://www.duralexusa.com/collections/duralex-bakeware * https://old.reddit.com/r/BuyItForLife/comments/4gxf5w/found_a_few_sources_of_borosilicate_glass_cookware/ https://old.reddit.com/r/BuyItForLife/comments/4gxf5w/found_...

rini17 2y ago

Im in Europe where ISO standard borosilicate glassware is common. However it is softer and more easily scratched by sand grains than soda-lime glass. Sand can get into food from vegetables or herbs. I had such scratched borosilicate tea kettle which shattered completely shortly afterwards. So this might be the core issue and now I take the disclaimers "never use if scratched" seriously. Lab reagents are much less likely to contain sand grains so it won't happen there.

infinet 2y ago

Thanks for the link! I didn't know they were using soda-lime glass and still call it Pyrex. In the meantime, the Pyrex labware remains real: I routinely pour liquid nitrogen into room-temperature Pyrex beakers without issue. That is a sudden temperature change of 220°C or 400°F.

cantrecallmypwd 2y ago

Everybody knows Pyrex started cheaping-out on use of borosilicate glass about the time they changed the logo on measuring cups. "Pyrex" "glass" is mostly ordinary glass now and pure garbage because of the corrosive effects of long-term corporate enshitification.

Aloisius 2y ago

I just hate that the modern Pyrex measuring cup markings wear off in dishwashers. I have new Pyrex measuring cups that are unreadable after a couple years while 40 year old ones that look brand new.