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Apr 25, 2008 05:28 PM

Pyrex baking pan: not in toaster oven?

I was hoping to do some baking in my fairly large (.7 cu feet) toaster oven, but when I looked closely at the instructions for my new pyrex pie-pan it says not to use it in a toaster oven. Anyone use one in a toaster oven? Isn't 350 degrees in a toaster oven the same as in a regular oven, or does the proximity to the heating elements make a big difference to pyrex?

thanks for any info

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  1. Pyrex told me it's the proximity to the heating unit. I wouldn't use it in a toaster oven as it's been known to explode in even a regular oven. Le Creuset told me their stonrware can be used in a toaster oven though.

    3 Replies
    1. re: blondelle

      Wow, I just had a look at this page:

      I think I will be throwing away all of my pyrex pie pans. Too bad, they were cheap and worked well. I had no idea that explosion was a potential problem when using pyrex. Can anyone recommend and good, inexpensive deep dish pie pan?

      1. re: foo1024

        i love my anchor hocking glass deep dish pie pan, however, the website has a warning that clearly states their glassware should not be used in a toaster oven.

        but if you're looking for a good one to use in the oven, mine has served me very well...

        1. re: goodhealthgourmet

          It may depend on the toaster oven and operating mode. Smaller ovens, especially in toast or broil mode will produce a concentrated heat. A larger one set to bake at 350 would be much less of a problem. If the oven just uses a bottom element during bake, setting the glass pan on suitable metal sheet might also diffuse the heat.

    2. Never use a glass baking dish in an oven with exposed radiant heat elements. If it's only air heating your glass dishes, you should be fine. But, when strong infrared is used (as in heating elements in many electric stoves which are exposed inside the oven) you stand a good chance of encountering problems. The reason is uneven heating, especially on the parts of the glass that aren't in contact with food. When the glass is hot, it expands and warps the piece. Depending on how sudden the change in temperature, the temperature of the air in the oven, the temperature of the food, etc., this can cause the glass to crack or shatter. Also, the glass, while in the hot oven, can deform more easily in response to those stresses. However, once the pan is pulled out of the oven, the parts not in contact with food (which were the hottest) are the fastest to cool, and cool the most, thus creating stresses from shrinking. However, since the glass piece is now cooler, it can't deform as easily as in a hot state, which leaves your cold glass dish in a 'stressed' state.

      Anytime glass is stressed it usually won't break *unless* there's a small flaw or scratch in the glass. Then, the stress gets concentrated near the flaw, and if there's enough stress, the glass starts to break. Notice I said 'starts to break'. Since the initial break is itself also a flaw, it causes more breaks, which cause more flaws, which cause... well, you get the picture. Essentially, all the stress in the piece is relieved at once, with the net effect that the piece shatters itself, or 'explodes' into many small bits.

      For an extreme example and some visuals of the phenomenon, do a search for "Prince Rupert's drops". There are a couple of good videos on youtube:

      And this one on glass annealing:

      1. Okay guys, my tablet is acting crazy, but, hopefully you will be able to read this and help me solve my mystery. I apologize if I am posting in/on the wrong place. I saw Pyrex and thought this was it... So...
        We have one of those all glass tea kettles for the stove top. ($10. from Bed, Bath,Beyond. Pyrex, I believe. Small black plastic lid. Wire coil goes under pot while boiling.)
        Anyway, been using same pot for over 3 yrs. Sits on stovetop, 24/7, only there to boil daily water for tea, throughout the day... Just sits there, year round, day in, day out, in a 70 degree Kitchen. Either tap ( Well water) or filtered water from door in fridge is used. (Fyi-About 2 yrs ago, my mom melted the black lid, big shock-lol, so she does not use it, anymore. Not really important to the story-or needed, but, you may ask why it wasn't being used. Mom also didn't like the whistling sound...So, it was either this glass teakettle, or boiling water in a saucepan, like my Grandma... Anyway, back to the story ...Basically, NOTHING HAS CHANGED FOR OVER 3 YRS and this glass teakettle... (Again, lid not used for past 2 yrs, but that is okay, as we never fill up the kettle to top with water, anyway... Just make enough water for 1 cup or 2 cups...) Many times, we just take the amount of water we need and leave the rest, to reuse later on. SO, the water that sits/stays/not used in the kettle, goes back to room temperature. Fyi- We use this glass kettle maybe once or twice a day. That is all. NOW, the good part. Last week, I went to boil water. Put some water in, about a cup and a half, put the stove on hi, as per last 10 yrs... ( We have owed SEVERAL of these glass tea kettles, as they are healthier, than the other materials, etc... Fyi- They just break from being dropped, lol...)
        Anyway- back to my story...~After just a few minutes, I happened to be walking by the stove, only a foot and a half from the burner and ALL OF A SUDDEN... A HUGE, LOUD POP, CRACKLE and... ( NO, not cracked glass, like I thought...) It was a scalding, screaming, shooting in the air, 3 ft, piping hot, of crackling WATER!!! It was a shooting geyser, up into the air and IT PLOPPED BACK DOWN, ONTO the FLOOR!... It did it several times... I was so scared. I honestly, thought that the glass was going to shatter all over the kitchen and was going to hit me in my eyes. I was so glad that it happened to ME, instead of another family member, who isn't as quick thinking. : ( I covered my eyes, shut that thing off, dumped that Devil water, lol, and hid that glass kettle, so nobody would use it, ever again. If I hadn't been there to witness it, I would NEVER have believed it. If my eyes had been only a foot or so closer, or if the glass had shattered, I may have gone blind. It was one of the scariest things to ever happen to me. I understand that you should use the lid. However, the lid really is NOT needed. if you are only boiling half the amount of water, or, you don't need the "whistling " sound to tell you, that your water is ready, you do not need a lid. A normal pot of water boils and then it is done. It does not violently shoot into the air and fall back down onto the floor, below. Normal, boiled/boiling water simply DOES NOT do that. WHY did it shoot into the air, SO VIOLENTLY ??? I thought maybe, the water was tainted. But, it is not. We have had/ used the same water for over 35 yrs... When I told my mom to immediately stop using this kettle and why, she said, " Oh, yeah, that's been doing that, lately..." I told her no more. She is 80 yrs old and just doesn't get it... So, sorry to be so long winded, ( It is 3am-and this is really bugging/upsetting me!) but, can anyone solve this mystery?? Yes, the kettle gets washed out, one in a while. Lol.. Over time, would unseen fissures, cause the water to shoot up into the air, violently, like a geyser and snap and pop, as if an explosion would happen??? Sediments from the boiled water?? : ( Slow decay of the glass?? Violent eruption of the water causing the glass to shake violently, on the stove top, too. I hate unsolved mysteries... (And no, no sharp changes in temperature. At all. None. Nada.) It also does not matter what type of stove we use. Same stove 20 yrs. Please let me know what you think might have happened... I would be thankful for any theories... Thank you ahead of time. : )

        10 Replies
        1. re: FeistyGirl007

          well, I copied off your post and used the "Enter" key to make it readable. tablets are great, don't know if that is how it all wound up as one single run on sentence...

          the formation of "explosive bubbles" is likely due to the mineral buildup on the inside, specifically the bottom, of your pot.

          as water reaches the boiling point, it takes only a slight nudge to go from liquid to gas. and the nudge is not only a temperature nudge, a physical 'bump' can also precipitate that effect - and no you don't have to bump the pot, just the normal vibration from the pot 'simmering' is enough to initiate a rapid phase change.

          if you boil water in a large metal pot, you'll see little bubbles forming at spots just before the whole pot breaks into a boil. these are "initiation sites" - microscopic to near microscopic points where the temperature will 'spike' - water turns to steam at those points - steam aka water vapor - occupies (working from memory here....) something like 1200 times the volume as water at the boiling point still in liquid form.

          when this happens in a large open pot, you get a burp. when this happens in a pot with a small diameter 'neck' - it makes a volcano.

          1. re: PSRaT

            TO PSRat----> Thanks so much, for re-posting. No, that run on was not intentional. A few weeks ago, I got a 21 inch "All in one desktop/tablet". It is making me crazy, as it is a hybrid, neither full desktop, nor full Android. It is the "Wild West." Of course, no manual. This is the only site showing up in 2 inch letters, giving me a massive headache, until I can fix it. : ( No,I have done nothing differently and this tablet keeps cutting out and shutting down, too... Ugh.
            Anyway, thank you for your explanation! That is what I felt was the reason, also. No other explanation that I can see. The problem is that there is just no way to tell when the kettle has been used for too long and must be replaced. Ours still looks fine and is intact. My mom still wants to use it ! : ( Anyway, thanks for your input. I really appreciate your taking the time! p.s. I just found out, that mom had been using it without the metal coil, for months... I know it is possible, just never safe... : ( Thanks again. ~Leslie : )

            1. re: FeistyGirl007

              ain't modern doohickies marvolous..... they sometimes do require taming. a 3 lb hammer is my favorite taming tool (g) but then again I have a low tolerance for user friendly devices that really aren't.

              theory holds you can chemically clean out the pot. try half-half vinegar water on low heat. the pot residual is almost certainly calcium type deposits which the vinegar will dissolve. rinse, repeat, rinse.

              past that look for commercial products to clean coffee makers.

              1. re: PSRaT

                PSRat- LOL... and...Thanks, you are correct! I will do that vinegar thingie... Don't know why I didn't think of that before... LOL... Take care of that hammer and thanks again! : D

          2. re: FeistyGirl007

            That kettle is made by Medelco, not Pyrex. You didn't have enough water in it. Don't let it boil dry. Perhaps the damaged lid contributed to the problem.

            1. re: GH1618

              GH1618- Thank you, but no, you did not read it correctly. I WOULD NEVER LET SOMETHING BOIL DRY. NEVER. How else would there be water shooting up into the air, with more to spare?? It was plenty, full of water. The water should have simply been BOILING and bubbling up. THAT is normal. This reaction was positively VOLCANIC. The reaction, almost a chemical reaction, was a violent - shooting up into the air of water. The lid had NOTHING to do with it. Millions of people around the world, every day, boil water, WITHOUT A LID on their pot. PSRat was correct. Micro sedimentation is most likely to blame... A vinegar cleaning should to do the trick.
              I am sorry, but, I was very sick in bed, so I couldn't check specifically. I said I thought it was Pyrex, because it was clear glass. But, it really did not matter, because the glass did not break. Late last nite, I got up and checked. It was Medelco, Germany. Yes, Medelco. However, in this case, it really does not matter. The make/company and the lid is irrelevant. That lid is only there to make the whistling sound, to alert you that the water is boiled and ready. A whistling tea kettle. Nobody in our home is under 45 yrs old and would boil in a container, without sufficient amount of water. It is most likely, as PSrat stated, a buildup of minerals. But, I thank you for responding! Take care... : )

              1. re: FeistyGirl007

                You wrote "a cup and a half." That means it would be in danger of boiling dry with a little inattention. The small amount of water, meaning more room for steam, probably had something to do with the problem.

                1. re: GH1618

                  GH1618---> Okay, I understand why you would say that now. Fyi- it is a very small kettle to begin with, not your standard, normal size tea kettle. When you have all adults living in the house, you tend to do your own thing and boil just the amount of water needed for you. Not to be wasteful. You keep a watchful eye on it and (after 30 - 40 yrs of doing this), you get a sixth sense about timing and when to go back and get your water. No problems for 40 yrs... until now. (Mom had no problems for 60 yrs, until now.) Anyway, the Kitchen was only in the next room and I was going to go open a window in there and was also ready to go get my water/turn off the kettle anyway- when I heard an unusual "popping" noise/sound coming from Kitchen. That is when I went into the Kitchen, walked past the stove to open the window, heard and then noticed the water shooting up into the air... all simultaneously. Curiousity made me put my head over the kettle to investigate. Yes, it took me a nanoscond to realize I was being an idiot. LOL... What is surprising, is that it happened early in the boiling process, not later on, as there was still enough water left in the pot....I had not turned it on and left it to go outside. It was being watched. Anyway...the rest is in my post above. The REALLY odd thing is, what the heck is in my well water?

                    1. re: GH1618

                      The miniscule, mineral buildup at the bottom of the kettle.

          3. "Pyrex" is no longer borosilicate, it's just tempered glass and has a nasty tendency to shatter/explode with heat shocks. Toaster ovens don't have very good temp control and the heating elements are quite close to the objects you put in them, so I'd not use a new glass anything in one.

            Someone got all torqued up about infinitesimal amounts of boron leaching from borosilicate glass and banned it for food. If you want real Pyrex, you have to find vintage.


            1 Reply
            1. re: psfred2

              It isn't just the closeness to the heating elements, it's the direct radiant energy. Toasting is not the same as baking. Pyrex glassware is for baking.