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Oct 7, 2012 05:26 PM

Pyrex explodes?

I was making wings tonight. I do the Alton Brown steam, cool, bake method. I put a rack on top of my Pyrex 9x12 glass baking dish, as I have done many times before. About 10 minutes in, the pyrex explodes. Sounded like a bomb went off in my oven. It looked like when a car window breaks. Entire oven covered in broken glass.
What the hell?

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  1. Over on the cookware section there has been a long posting on this subject.

    1 Reply
    1. re: escondido123

      Thanks. Obviously I'm not alone.
      My baking dish is (was) at least 20 years old.
      I'm surprised they can still sell this stuff.

    2. Much discussion of this topic has gone under the bridge. The older Pyrex apparently hasn't been known to explode as much as the newer stuff, something about China's unregulated manufacturing practices. My Pyrex is all old stuff from yard sales but after reading some of these posts I'm getting nervous about baking in it.

      BTW has anybody had Pyrex blow up in the microwave or is it just the thermal oven?

      12 Replies
      1. re: Querencia

        I use Pyrex in the micro, but never in the regular oven. I had a pie plate break when I took it out of the oven a few years ago. I've read so many examples of Pyrex breaking or exploding that I see no reason to take a chance.

        To the OP, there are threads about this on CH. Do a search for a thorough discussion. The original Pyrex has not been made of the original glass for many, many years. The currently made product is not as durable as that from former decades.

        Some people say they have no problems, but plenty of us have experienced what you have. I wouldn't use it in the oven. Why take a chance?

        1. re: sueatmo

          Pyrex® bakeware has been made of soda lime glass for more than 60 years. Borosilicate glass was used before that and is still used for laboratory glassware. Soda lime glass is used for home cookware because it is safer.

          1. re: GH1618

            +1. As for soda lime vs borosilicate glass safety. It is here and there. Borosilicate glass has better thermal shock durability, whereas World Kitchen claims that its soda lime glass has better physical durability.

            1. re: Chemicalkinetics

              The safety issue has to do with the characteristics of the shards after it breaks, not whether it breaks.

              1. re: GH1618

                Oh I see where you are getting at. Good point. My experience of broken labware (borosilicate) is that they are not that bad. Now, the broken crystal glass I had recently was pretty bad. Very big pieces, very tiny pieces, all shapes and sizes, and they were all very very sharp.

                1. re: Chemicalkinetics

                  You are very right. Someone I know picked up some broken glass with his bare hands and ended up getting a very bad infection from an almost invisible shard that went into his finger. Now I always wear rubber gloves when dealing with any broken glass.

        2. re: Querencia

          Pyrex® glass is made in the US, not China.

          1. re: Querencia

            <The older Pyrex apparently hasn't been known to explode as much as the newer stuff>

            Maybe people don't talk about it as much because the internet was not around. Or maybe because the glass formula changed from borosilicate glass to tempered soda lime glass.

            <something about China's unregulated manufacturing practices>

            Definitely nothing to do with China, since Pyrex glassware is still made in USA.

            <anybody had Pyrex blow up in the microwave or is it just the thermal oven>

            A lot less likely to blow up in microwave.

            1. re: Chemicalkinetics

              "... the internet (was) not around."

              Exactly. There is a reporting bias due to the easy availability of public forums such as this one. The more alarmed one is that a piece of glass should break, the more likely one is to go public with a complaint.

              Most people who use Pyrex® without problems don't bother to mention it. I am an exception. I will soon be making a couple of my traditional pumpkin pies in my 40-year-old (or so) Pyrex® pie plates, and I expect to report an uneventful baking experience.

            2. re: Querencia

              Mine did in the microwave. A small bowl that I was heating chicken broth in. Millions of little pieces. I've been nervous about using the stuff ever since, and I am careful about putting it down on a dry towel when hot.

              1. re: Querencia

                Pyrex is not and was not made in China. It is made in the US.


                And we use it extensively for storage without issue.

                1. re: Querencia

                  Querencia, I think you may have read about unregulated manufacturing practices in China here:

                  Already in that thread, it was pointed out that Pyrex glassware is not manufactured in China.

                  Since then, you have referred to "recent-vintage Pyrex being made in China" in a couple of different threads:
                  and others have again responded that Pyrex glassware is not, in fact, made in China.

                  There is a lot of bad stuff coming out of China (alongside a lot of high quality products). And I'm no fan of exploding glass in my kitchen. But the link between China and exploding Pyrex is an Internet rumor and it would be helpful to stop spreading this misinformation.

                2. Had it happen about 2 years ago and that was the last time it went in my oven.

                  2 Replies
                  1. re: Dax

                    Well of course. Why would anyone put a heap of broken glass in their oven?

                    1. re: GH1618

                      Touche. The other two no longer go in the oven.

                  2. By the way, the original post seems to suggest that the instructions were not followed somewhere. The Alton Brown recipe does not call for "baking," it calls for "roasting":


                    Roasting is cooking with a high, dry heat. But a Pyrex® baking dish is not a roasting pan. The safety instructions call for covering the bottom with liquid if food suspended above it can release moisture which drips into the dish.


                    The risk of breakage when roasting something over a dry Pyrex® baking dish is pretty obvious, I think.

                    1 Reply
                    1. re: GH1618

                      I agree with you, GH. Dripping from a rack onto hot Pyrex is a risky scenario. Some of the Pyrex-shattering stories I've seen can't be attributed to thermal shock, but this one seems explainable.

                      As far as that second link of yours is concerned... "Sandra Lee Shares Simple Rules for Cooking With Care" ... lol!

                    2. Here is a nice video (awesome if I may say) about the extreme thermal shock on tempered glassware. Scroll down and enjoy.