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Glass cook tops

I have an old pyrex Coffee and Tea pot, and Corning Ware pot, I have a new stove, and need to know if I can still use them????

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  1. It depends on two things. (1) Are the bottoms of the pots absolutely flat, in other words does the entire bottom make full contact with the glasstop's burner surface? and (2) Are any of the pieces the kind where you are supposed to use a triangular wire "spacer" between the pot bottom and the burner surface?

    I had a couple of vintage Pyrex pieces (notably the double boiler) whose instructions/warnings clearly said that the bottom shouldn't directly contact an electric stove's burner coil. Don't know how old your pieces are but mine were from the 1960s.

    I'd guess that if they weren't supposed to be used directly on a non-gas burner then, they probably shouldn't be used on them now either.... Just a thought.

    The flat bottom is the most important thing though.

    I still have two Corningware small covered casseroles with the Pyrex lids but to be honest I've never tried them on our glasstop; only in the oven, in this kitchen. I've always wondered whether they would be okay on the glasstop but not enough to risk them fragmenting spectacularly into bits, with the resulting mess, if I was wrong, LOL!

    1. I don't want to be mean about this, but I recommend you ditch your Corning Ware and invest in a decent few stainless pans, or pans of your choice for your new cooktop. I use stainless, cast iron, and a couple of non-stick frypans on my older glass top. Many, many moons ago I used Corningware on a gas cooktop. It was murder. It doesn't work nearly as well as metal. There are many threads here with discussions about what sort of starter pans people should buy. My advice is to shop around and pick pans up to see how they feel in your hands. At first you can buy a couple or three pans, and then as you find them, you can add more. Or you can go the set route, and buy a nice set of stainless. The brands I'd recommend for someone not wanting expensive top of the line, would be Cuisinart, Tramontina, Anolon. You can handle several sorts of pans at Bed Bath and Beyond. Really, choosing stuff for your kitchen should be fun.

      1 Reply
      1. re: sueatmo

        I do have very nice Williams Sonoma pots and pans they work great on the new cook top, but I also like my Pyrex, and Corning Ware coffee and Tea pots! Not giving them up!

      2. The info that came with my glass top stove said you should be very careful about using glass pots because if the liquid in the pot evaporates and it goes dry the glass can fuse to the burner. I think they warned about another material but I can'r remember.

        2 Replies
        1. re: cajundave

          That makes sense (thinking about watching glassblowers at work and how they fuse different pieces together via a flame): If both the glass pot and the glasstop stove reach the same high temperature, they would probably both soften and ultimately melt/fuse together, and then when the temperature drops (burner turned off) they would act just like the glassblower's piece and become one fused item.

          I know the stovetops aren't "pure" glass (mine is Schott-Ceran) but as long as the melting points of the pot and surface are close enough, they probably would do the same thing (melt/fuse).

          Was the other material aluminum? Because I just looked at the Schott Ceran use page and it does have a caution against that. It also mentions "glass-ceramic" but not pure glass/Pyrex.

          http://www.us.schott.com/hometech/eng...

          1. re: skyline

            When Corning the company was making Corningware in the 1970's, the company came out with the first smooth-glass-top stoves and cooktops. The Corningware dishes were made of Pyroceram, and the cooktops were made of Pyroceram. Corning even went to the trouble of making sure all of its cookware (and the cookware given with the stove) had flat bottoms to work properly on the smooth-top stoves. So basically what we're talking about is glass cookware working on glass smooth-top ranges by the original maker. I've never heard that the Corningware melted to the cooktop! I even have a portable Corningware electric smooth-top skillet that no matter how hot the unit gets - there is a thermostat that regulates the heat on all electric stove-tops - the glass is not melting. Corningware, like most glasses simply are not going to melt or become soft at anything close to the usual temperatures found in the normal kitchen. Corningware - the pyroceram kind (blue-flower dishes, etc) easily withstands a range of temperatures from 800 degrees to 3,000 degrees - temperatures not found in normal kitchens. (That is why it was used for missle cones and space craft in the 1950's.)

            Of course Pyrex, the clear glass stuff that baking dishes, coffee and teapots are made out of is a completely different topic - those were not good for a smooth top range. One - often the bottoms were not really smooth in the first place. We are not talking about those items.

            Of course, over time the kinds of glass used in smooth-top ranges may have changed. Maybe different formulas of glass are used, etc. However on electric stoves - (coil, smooth-top, etc.) like in electric ovens there is a thermostat that regulates the temperatures. There is no way that any maker of cook stoves is going to allow 800 degree and higher temperatures - the lawsuits would be just too great.

            Now there has been a general movement away from the Pyroceram (the glass-ceramic kind) brand of Corningware (by a company called World Kitchen - the maker of current Corningware) - toward the "stoneware" kinds of dishes - that were not rated for the stove-top. These days they also make Pyrex baking dishes. I suppose (that's just me) in order for users to not become confused about which Corningware is which - it is easier to just suggest that not any be used. When in doubt about something - it seems that it is easier these days to just say "No".

            To sum up - I think that the idea that the glasses will fuse together is a myth. I think that in this lawsuit crazy world it is better for stove-makers to "limit" the kinds of cookware that can be used on their stoves - simply because there is a great variety out there (cookware, conditions, how people do stuff, etc.). Sometimes the stuff that is used today IS inferior to the stuff used in the past - along with advisories to limit usage - because it is better if the folks just buy another one when it breaks (rather than it not breaking in the first place). These are just my thoughts. There are times when stuff just changes - and you have to change with them - also.

            Mike

        2. My wife and I discovered a number of cracks in our glass top stove one morning. They appeared to radiate from one location. It looked as if something, like a can, had dropped on the stovetop from the cabinet above it. Yet, neither one of us observed anything like that or any other physical action that could have caused the damage.

          This remained a mystery for quite a while until one night my wife was watching the “Kate plus Eight” show or whatever it was called, the reality show about the couple with eight kids. Apparently, the same thing happened to her but in her case the whole top shattered.

          It seems that if you take a hot lid off of a pot of boiling liquid and place it on the stovetop, when it cools the moist air will contract and form a vacuum powerful enough to crack the glass. I had noticed this vacuum effect before but didn’t think anything of it. Boy was I wrong.

          So, keep your hot, moist lids off of the stovetop and you shouldn’t have any problems with cracking glass.

          4 Replies
          1. re: TomDel

            I've placed hot moist lids on my glass cooktop for a decade, and I have no cracks. I've noticed the vacuum effect as well.

            Is this warning in the cooktop's manual?

            1. re: sueatmo

              I've wondered if this vacuum with hot/moist lids is a hoax.
              I've also had people tell me to be leary of letting salt or sugar fall onto the glass cooktop and have wondered if this is also a hoax.

              1. re: Rella

                By hoax, you mean the vacuum effect could cause crack? Or a hoax in the sense that there is no "vacuum effect?" I've experienced the stuck lids which seem to be vacuum sealed to the cook top. I have to slide them off. But I've never had a crack. I hope Tom Del had his cooktop replaced free from the mfg!

                1. re: sueatmo

                  I, too have had stuck lids which seem to be vacuum sealed to the cook top and slid them off. I have previously wondered if it were a hoax that the stuck lid would cause a cook top to crack, just as I've wondered if salt or sugar dropped onto a cooktop would cause a cooktop to crack.