KaiserPro 2 days ago

In the UK PYREX cookware is always borosilicate. So it was a bit confusing to hear americans say how shit their "pyrex" glassware is.

Mind you, most of our oven proof glass is decent enough to be put in the oven and then dumped on a cold surface.

  • fmajid 2 days ago

    That's because a French company now owned by a US Private Equity firm, Arc International Cookware, owns the license for Europe, and as they have some pride, continue to make it with borosilicate.

    It's available in the US under the "Arcuisine" brand.

    • ornornor 2 days ago

      > US Private Equity

      > has some pride

      Money has no smell nor pride.

      • dijit 2 days ago

        Some PE firms do understand brand image and market segmentation based on this and know what it’s worth as a dollar-amount.

        I’ve been in the room a few times where they broke down the math for me.

        • crote 2 days ago

          That's the most brilliant part of the PYREX vs pyrex situation, isn't it?

          Lowercase pyrex bought the naming rights and gets to benefit off selling cheap products at a premium price, while uppercase PYREX maintains their brand image for them by selling genuinely good glassware.

          • pinkmuffinere 2 days ago

            I think you’re wrong about this. 90% of customers will not realize there is a distinction, and so there’s just confusion over the general state of things. My guess is that splitting the brand in half like this is actually more costly overall than just committing to one path

            Eg, imagine if mazzerati also made a mid-market vehicle. It would lose some cachet, and also wouldn’t make much profit off the midmarket item. In the other side, if Walmart stocks premium goods, they won’t sell because they’ll be perceived as too expensive by the Walmart audience.

            Edit: anecdotally, I once used the weaker variety, the dish exploded on me, and I luckily was not maimed. The floor was not so lucky, it is still pockmarked. The lesson I learned is: only use metal in the oven, no matter what.

  • nialv7 2 days ago

    I have bought PYREX branded cookwares that claimed to be borosilicate, but are not actually borosilicate.

    You can't visually tell borosilicate and soda-lime apart easily. There is no difference in color (the green vs blue difference is because of other impurities). There is no significant different in refractive index. The only reliable test you can do at home is density (soda-lime 2.52, whereas borosilicate ~2.23, unit g/cm^3).

    I measured my "borosilicate" cookwares and all of them are in the ~2.5 range. Turns out they just false advertise. A couple "made in China" beakers I got on Amazon turned out to be borosilicate though. Take that however you will.

    • MattJ100 a day ago

      I'm curious about the method you used to measure this accurately at home.

      • chmod775 a day ago

        A scale and liquid displacement measurement presumably.

    • IshKebab a day ago

      How are you measuring density to that accuracy?

      • chmod775 a day ago

        You don't have to measure very precisely when the difference in density is that large and the item is relatively large and heavy.

        I'd be more concerned about some assumptions made. For instance I found that some alumino-borosilicate glass has densities that can reach above 2.5 g/cm³. I have no idea if you'd make cookware from that, but it's also a borosilicate glass...

        • IshKebab a day ago

          We're talking a 10% difference in an object that probably has a complex shape of varying thickness.

          I don't think he's got a solid block of glass.

          • giantg2 a day ago

            Water displacement doesn't care about all that.

  • graemep 2 days ago

    > Mind you, most of our oven proof glass is decent enough to be put in the oven and then dumped on a cold surface

    I would have thought that is a pretty minimal requirement. Where else would you put something you take out of the oven.

    I assume anything that can go in the oven can go from oven to table and fridge (but maybe not freezer) to hot oven.

    • HPsquared 2 days ago

      One of those cooling racks where it's not making full contact.

      • ghaff 2 days ago

        It’s a bigger deal with baking brownies but putting a lasagna on a cooling rack before putting it on your dining room table even with hot pad in probably a good idea.

        • graemep 2 days ago

          That is what trivets and mats are for.

      • graemep 2 days ago

        Do not have one of those! I want to keep hit food hot!

        • 2muchcoffeeman 2 days ago

          A cooling rack is not a heat sink. It’s a place to put hot things because not all surfaces are heat resistant up to cooking temperatures and not all hot vessels can be dumped on a cold or potentially wet surface.

        • ewoodrich 2 days ago

          I don't think it changes the rate of cooling that much, just more of the the heat is transferred by convection to the surrounding air instead of conduction to the surface (which for a stone countertop has a lot of mass to absorb heat making them notorious for blowing up hot glassware on contact).

          • fibonachos 2 days ago

            > free heat that we couldn’t control

            I understand the appeal of free. It’s the idea of someone else controlling it that gives me anxiety.

          • badc0ffee 2 days ago

            So basically, an insulator.

    • selimnairb 2 days ago

      We once had a glass baking pan EXPLODE!!! after being taken out of the oven and placed on a cold stovetop, but with the window open in early December. (We lived in an apartment that had free heat that we couldn’t control so we often had to open the kitchen window when baking during heating season.)

    • KPGv2 2 days ago

      > Where else would you put something you take out of the oven [other than a cold surface?]

      A room-temperature surface. The only cold surfaces in my house are in my freezer and refrigerator.

  • stuaxo 2 days ago

    I wonder if exploding cookware would get a British safety kitemark ?

jzelinskie 2 days ago

I watched a video recently that dove deep into this as well[1]. It turns out there's not an easy way to figure out if it's borosilicate other than if it has "made in France" on it or if you know it was purchased in Europe. AFAICT, you can't really buy borosilicate Pyrex in the US.

The video does also show off a cool "mineral oil test" to tell the difference, but probably is only effective if you had something to compare it against.

My takeaway though was that I need to thrift some Corningware, though!

1: https://youtube.com/watch?v=2DKasz4xFC0

  • foofoo12 2 days ago

    Mineral oil test bookmark: https://youtu.be/2DKasz4xFC0?feature=shared&t=873

    It's a non destructive test. Quote from the video (with funny youtube transcription spelling errors):

    "Without getting too technical, the gist is if you put the mineral oil in a vessel made of boroilic and then dip another glass made of boroilicate into it, that glass will seem to disappear while others will not. So I filled a vintage what I think is made of borosilicate Pyrex vessel with mineral oil. Then it dipped in a vintage what I think is made of boro silicut loaf pan and it seemed to disappear right before my eyes. Eureka I thought the experiment works well until I dipped a new Pyrex piece lowercase that I know is not made of borocyic and it disappeared too. Once again, another spokesman at the Cording Museum of Glass that I reached out to said that even the mineral test isn't a sure thing. According to Brady Spalling, he says in order for glass to quote unquote disappear in oil, the glass being submerged must have a similar refractory index, which allows light to pass through both without significantly bending. Mineral oil and borosyic do have similar refractory indexes. So what you've heard is correct. This method is often used to quickly ascertain whether a glass object is borosyicate. However, variability of glass recipes makes it difficult to rely solely upon this method. In short, it may work and it may not."

    • s0rce 2 days ago

      I'm surprised that there is enough difference between borosilicate glass and soda lime glass refractive index. They are also both slightly mis-matched to mineral oil but I guess good enough for a visual check. Appears its not consistently reliable.

      Also, its refractive index not refractory.

    • JKCalhoun 2 days ago

      In the video he claims it does not work in his case — but I saw a very clear (ha ha) difference between the two. You could easily see the edges of the non-boro glassware.

  • fmajid 2 days ago

    Soda-lime glass has a greenish hue (look at it sideways). Borosilicate is blueish.

    • KingMob 2 days ago

      If you'd read the article, they literally address this. They said the colors are due to unrelated impurities, and are not a foolproof guide.

    • s0rce 2 days ago

      This depends on the source of the raw materials, the green is typically from iron and you can have higher purity soda lime glass that is much more clear. I didn't realize there was a visible blue tint in consumer borosilicate glass, I wonder what causes this.

  • zahlman a day ago

    I've recently been getting this exact video suggested to me frequently in the sidebar, and I have no idea why.

bob1029 2 days ago

I used to worry about this but there's not a meaningful difference if you have any care for the tools and basic precautions. Borosilicate glass also tends to be more dangerous when it breaks. I've broken far more pieces of glassware due to mechanical reasons than thermal reasons.

Pyrex doesn't have a maximum temperature limit in a kitchen environment if you are careful. Preheating the oven is the #1 way to prevent issues. If you put a piece of glassware in an electric oven without preheating it, you can create massive temperature deltas between top/bottom. I can get an iron skillet beyond 700F in my electric oven if I leave it in there while it's preheating for a set point of just 450F. If the heating element has direct line-of-sight to the cookware, you always need to be wary of radiative heating effects.

  • ricardobeat 2 days ago

    Preheating the oven can also increase the risk of thermal shock shattering the glass. The maximum tolerated temperature change for soda-lime glass is only ~60C.

    Not being able to put it under a broiler is a huge disadvantage for nicely finishing dishes like a lasagna.

    • hyperbovine 2 days ago

      I have had this happen. Mac and cheese into the preheated oven, boom. Glass shards all over the dishes on the lower rack. Almost ruined Thanksgiving.

      • bch a day ago

        I thought preheated was the LEAST shocking to devices in the oven, otherwise they're in the cold oven (fine) until you start heating and they take the full energy from the elements trying to get the env to temp(not good). I guess too it would depend what the dishes are being set on in the oven - wire rack versus pizza stone/steel, ... I wouldn't think the hot air (poor conductor) would be as shocking as the direct energy from the full-on elements.

        Unless your mac&cheese was premade, put into the fridge, then directly into the oven at cook time?

      • drob518 2 days ago

        Was that with PYREX/pyrex or just a random casserole dish?

  • acomjean 2 days ago

    >Borosilicate glass also tends to be more dangerous when it breaks.

    people say that, but from side by side comparisons of breaking both kinds, it really didn't seem to make a difference.

    Its not like car window "glass" that just pebbles.

    • mattmanser 2 days ago

      The pebbling in car window glass is safer, the pebbles aren't sharp. It's a deliberate feature that it pebbles.

      • procaryote a day ago

        The pebbles are sharp, they're just small and less likely to impale you

        Source: bleeding fingers picking up the pieces after a car break-in

  • abrookewood 2 days ago

    Yes there is! The lowercase one looses the writing/marking in about 6 months, rendering the measuring cups completely useless!

  • Modified3019 2 days ago

    Wow, I had never even considered that the pre-heating phase could potentially get things hotter than the normal cycling, but yeah that makes sense. It’s just broiling from another direction.

    I think my oven might cycle the bottom element even when pre-heating, possibly to prevent this.

  • Finnucane 2 days ago

    i’ve never had a Pyrex baking dish fail in the oven, whether it was an old one or a newer one. Any breakage has always been my own damn fault.

danw1979 a day ago

This page is insane. They Are frequently using PYREX, Pyrex and pyrex to refer to variously the same and different things.

  • Zanni a day ago

    Carefully distinguishes between PYREX and pyrex. Immediately launches a discussion of Pyrex.

  • DarkNova6 a day ago

    Sounds like most software documentation I have read.

Mayzie 2 days ago

Relevant video from Ann Reardon's How To Cook That about exploding Pyrex (and the difference between all capitals and all lowercase): https://www.youtube.com/watch?v=YVbkDAw4aJs

Turned out that distinction isn't too reliable when it comes to determining whether a product used soda lime glass or borosilicate glass instead.

ycombinatrix 2 days ago

That's crazy that Corning would sell out a brand name that they are still using.

zorgmonkey 2 days ago

If you're curious the only brand I could find easily purchasable in the USA that uses borosilicate glass is oxo. Their are some other results if you do a search on amazon, but I'm not very convinced those are really borosilicate glass.

  • dtagames 2 days ago

    In Texas, HEB sells its own brand of borosilicate glass cookware which is labeled as such on the front. All made in France.

  • Spooky23 2 days ago

    If you want borosilicate Pyrex, go to church bazaars and yard sales. The old stuff is better anyway.

    • drob518 2 days ago

      That seems the case for just about any product these days, unfortunately. In the modern world, all the products are cheaper but they all suck.

      • estearum 2 days ago

        You can almost always pay more (and look harder) to get better items, in my experience.

  • zem 2 days ago

    pretty sure marinex is borosilicate too

    • imp0cat 2 days ago

      You can relatively easily check this before buying, just look for the tint (usually best seen on the edges of the glass). Blueish = borosilicate, greenish = soda lime.

zabzonk 2 days ago

I remember when I was doing A-level chemistry at school circa 1970 we were told always to check that any glassware we were heating up a lot (or might be very exothermic) had the PYREX symbol on it, otherwise bad things could happen. A bit later, almost everything was PYREX.

  • logifail 2 days ago

    > when I was doing A-level chemistry at school circa 1970 we were told always to check that any glassware we were heating up a lot (or might be very exothermic) had the PYREX symbol on it, otherwise bad things could happen

    Speaking of "very exothermic" ... decades ago a lab colleague of mine once entirely blew out both (glass) sides of his fume cupboard while attempting to melt "ice" with a heat gun. Of course the "ice" that had formed in his flask during the previous reaction turned out not to be ice. The flask itself was later found in lots of very very tiny pieces.

    It was the loudest bang I've ever heard, happily he sustained only very minor injuries, with hindsight a minor miracle.

kfrzcode 2 days ago

I refuse to enter into joinder with this discussion, but for the record:

The all-caps name, PYREX, is the de jure, natural bakeware, created of the land (borosilicate). It has inherent, unalienable rights to withstand thermal shock. It is a true vessel.

The lowercase name, Pyrex, is the corporate fiction, the STRAWMAN created under the maritime law of commerce. It is a mere vessel in name only, subject to the whims and defects of its corporate creators. By purchasing it, you are unknowingly consenting to be governed by their rules of catastrophic failure.

Do not be deceived by their fraudulent conveyance. I do not consent to being a party to this contract. I am a free man, traveling upon the land with my original, common-law PYREX.

  • bombcar 2 days ago

    TYRANNOSAURUS PYREX will always win over lierex.

weinzierl 2 days ago

In Germany borosilicate glass is called colloquially "Jenaer Glass" named after the city of Jena.

https://en.m.wikipedia.org/wiki/Jena_glass

  • fmajid 2 days ago

    Probably because Schott glassworks was originally established in Jena as a sister company to Carl Zeiss.

  • oblio 2 days ago

    Same in Romania, we probably got the name from you. We just call it "iena".

  • thaumasiotes a day ago

    What happens in German with the vowel sequence in "Jena-er"?

    • weinzierl a day ago

      It's simply pronounced like separate a and e and does not turn into an umlaut.

dtrav 2 days ago

So there are three : PYREX borosilicate glass lab equipment, pyrex soda-lime glass cookware, and Pyrex borosilicate glass cookware made in France. Another childhood illusion shattered.....

wyclif 2 days ago

Has anyone written a better explainer about the difference? Corning's entry isn't that helpful. Particularly interested in the safety issues and practicality in terms of kitchen use.

Also, I'm told that IKEA's "MIXTUR" line of glassware is more Pyrex-like than actual Pyrex. Is that true?

  • numpad0 2 days ago

    Pyrex was the brand for Corning's borosilicate glass products, which is an almost all-around superior substitute for regular soda-lime glass. Better acid resistance, lower thermal expansion, higher softening/melting temperature, etc.

    Some marketing geniuses somewhere concluded that consumers wouldn't notice, and created the line of products that carry the confusing "pyrex" branding but aren't borosilicate based but just thicker or something.

    And now they have to have this page to explain the differences.

    • badc0ffee 2 days ago

      I thought the official "explanation" was that soda lime glass is superior because it is mechanically stronger than borosilicate glass, and most glassware breakage is due to impact, not temperature swings. But I'm not sure I believe it.

    • wyclif 2 days ago

      So PYREX denotes the Corning brand, and pyrex the imitation of the original (that explodes in ovens)?

  • the_mitsuhiko 2 days ago

    It’s borosilicate which is the original Pyrex.

killerstorm 2 days ago

The article is written like a low-grade blog spam, and yet it is corning.com.

They reference events out of order, etc.

  • chrismorgan 2 days ago

    And, when it’s supposed to be all about PYREX versus pyrex, they immediately start talking about Pyrex.

    The article is atrocious.

pbhjpbhj 2 days ago

It's some evil genius market segmentation on behalf of Pyrex management.

This sort of thing subverts the usefulness of trademarks. You buy from a traditionally upright company, but they just bait-and-switch you on the strength of their trademark and you might as well have bought any product labelled as pyrex.

This is why I like the concept of an "origin mark" that links to a full record of the whole supply chain for the product. Companies already have that information, exposing it makes buyers able to make [more] rational decisions and then capitalism can actually work to improve products.

That said, using the same trademark for different products in this way should invalidate the trademark (maybe UK TMA1994 S3 can be used in this way??).

  • crote 2 days ago

    How would this even work? Consider the following scenarios:

    - Company is fully acquired as-is, nothing changes to the product.

    - Business division is spun off as-is, nothing changes to the product.

    - Company closes current factory, outsources production as-is to another factory in a different country, nothing changes to the product.

    - Company makes minor changes to recipe, nothing substantial changes.

    - Company uses different recipe in current factory using current tooling, product is substantially different.

    - Same factory is used, production line is completely retooled, product is essentially unrelated.

    - Original factory is closed, original company now buys imitation product from a 3rd party factory and still uses the original trademark.

    - Trademark is sold, slapped on completely unrelated product.

    Clearly it isn't as simple as bait-and-switch. There are plenty of scenarios where a lot can change while the product stays the same, and there are a plenty of scenarios where almost nothing changes and the product is completely different.

    It gets even murkier when you look at product lines instead of individual products: at what point do you revoke the trademark when they sloowly switch to the cheaper recipe as part of the regular replacement cycle, with all new products only using the budget option and all the legacy premium products getting retired? And how is it going to work for anything more complicated than glassware - where the quality difference isn't a plain "borosilicate glass or not"?

    • pbhjpbhj a day ago

      >- Company uses different recipe in current factory using current tooling, product is substantially different.

      The product has ingredients, the product gets a label, the product label links to the ingredients; each ingredient had a label, that tree of labels links back ... this already happens, when an ingredient (which child itself be a product) is found to be inferior or spoiled the manufacturer can check their own products made with that batch of ingredient. 'All' we would be doing is exposing this data.

      Change suppliers, there code on the product changes (that could be by keeping a table of product UUID matched to batch number).

      Someone mixed peanuts in with the macadamia nuts and supplied 100 different manufacturers, now the public can look up those products that were affected just as much as the suppliers can.

      Someone bought a cheaper metal, for their bicycle frames, that shows in the product information linked from the origin mark.

      Someone changed the recipe of their chocolate bar to have more filler ingredients ... that should already show on the ingredients list.

      A company change their GPU, say, to use slower RAM, that shows in the product info as an ingredient. Binning? Not much help for that. Different manufacturer or different factory, that would show.

      It would expose a lot of information considered currently try to hide.

      Doesn't really do anything for fraud except that if you claim someone is your supplier (still) and financials don't show continuing payments then it's clear there is fraud there.

      Any further thoughts, very happy to discuss. I'm keen to work this up into a feasible system.

      pbhj AT alicious , com

giantg2 a day ago

Long and short of it is that the word Pyrex in any form is to be considered a marketing term. If you want borosilicate glass, then you need to to confirm the composition some other way.

locallost 2 days ago

Funny to me because just last week I week I wanted to buy a glass jug, and as a natural born procrastinator I just had to google products from Pyrex. Apparently the European products are still made of borosilicate glass in France. In the end I bought one from Anchor Hocking because it has markings etched in and a few people complain their Pyrex markings disappear. I did buy some dishes from Pyrex and they say borosilicate glass on the packaging (made in France).

  • masfuerte 2 days ago

    I have a 25 year-old European glass bowl. PYREX is etched quite subtly on the underside. I bought another one about five years ago. The word PYREX now appears in relief inside the bowl. So a spoon catches on it. It is more readable but less usable. I won't be buying any more.

nikolay 2 days ago
  • greymalik 2 days ago

    Why and why?

    • simondotau 2 days ago

      I clicked the link. The company claims to be making their product from borosilicate glass.

  • KPGv2 2 days ago

    I'd be really interested to know where their borosilicate glass is made. In my house, we have a rule that nothing made in China can touch our mouths or our food. Every OXO product I've ever looked at is made in China.

dtagames 2 days ago

The article makes a bad mistake when explaining borosilicate. It's more expensive than soda lime glass, not less.

KPGv2 2 days ago

This is exactly the thing trademarks are supposed to protect consumers against.

  • hermannj314 2 days ago

    I was hoping someone would say this. I think the virtue of the trademark is an implied warranty of the value of the brand.

    I would like to live in a world where deceptive trade practices did not exist.

    Imagine selling a "full-self driving auto-pilot hands-free car!" And then arguing all the letters are lower case in the brand name so all those dead drivers should have known better and should have bought the capital F version.

    • yencabulator 2 days ago

      Even if this case didn't involve two companies, it's a basic investor tactic to take a well-respected brand, start making the product from inferior ingredients, and pump pump pump while the money still flows. All that differs from that story here is that Corning split the labware and cookware companies.

  • yencabulator 2 days ago

    Trademarks prevent others from doing this to you. Corning did this to themselves, by selling the rights to the name without means to enforce what the name is used for.

dehrmann 2 days ago

> The new owner...recognized that the cookware didn't need to be quite as strong, and — to make it accessible to the average customer — it needed to be more affordable. With this in mind, they switched the cookware to soda-lime glass, a less expensive component. Soda-lime glass, now called pyrex, isn't as resistant to thermal shock, but it is durable enough for everyday cooking.

Was Corning's borosilicate cookware tempered? Tempered soda-lime class is more resistant to breaking from rough handling than borosilicate, so there's a real tradeoff between the two.

souenzzo 2 days ago

Are these new python package managers?

  • fracture7734 2 days ago

    Seeing the title I thought about the python type-checker Pyre

  • cap11235 2 days ago

    I read the title and thought it was about C++ iterop.

  • plantain 2 days ago

    Don't give them any ideas.

throw0101a 2 days ago

A recent video from the I Want To Cook channel on the topic:

* https://www.youtube.com/watch?v=2DKasz4xFC0

He references this FAQ from the Corning Museum of Glass (CMOG):

> The short answer is that the change from upper to lower case signified a re-branding of the trademark Pyrex® in the late 1970s but is not a conclusive way to determine, historically, what type of glass formulation the product is made from.

* https://libanswers.cmog.org/faq/398431

OhMeadhbh 2 days ago

Okay... PYREX is borosilicate, pyrex is soda-glass. What about Pyrex? (Where only the first letter is capitalized.)

I won't lie. This is shitty marketing.

hexo 2 days ago

Im kind of sure making difference between "PYREX" and "pyrex" is illegal here.

kazinator 2 days ago

That is such a deception. Soda-lime glass is just the everyday crap that beer bottles are made out.

anonu 2 days ago

For a moment I wondered what this python package does...

  • badc0ffee 2 days ago

    Obviously a FFI for REXX.

padjo 2 days ago

“World Kitchen in 2000, recognized that the cookware didn't need to be quite as strong, and — to make it accessible to the average customer — it needed to be more affordable.”

Some pretty strong bullshit vibes from this section. Feels a lot more like they decided to make the product worse because they knew the brand name would be enough. I doubt price is a significant factor compared to durability for the average home cook.

  • rdl 2 days ago

    There are a few other downsides to borosilicate vs soda lime in a home kitchen (I still have euro and vintage only); if borosilicate breaks it is somewhat more dangerous.

bethekidyouwant 2 days ago

Corning stopped making those glass pots and were the best…

gadders 2 days ago

Essentially PYREX got enshittified into pyrex.

ChrisMarshallNY 2 days ago

Just a note: The second “Pyrex” in the title should be all lowercase (“pyrex”).

Since the article is discussing the branding, this is relevant, as they use “Pyrex” in the article, to refer to “PYREX.”

  • dang 2 days ago

    Fixed now!