Common Sense and Glass Cookware

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Heather says:

It has just been brought to my attention that Pyrex cookware has been receiving some attention from Consumer Reports via the Consumerist. I love glass cookware and I will continue to use my glassware for baking, however there are a few precautions one should always use. Glass, even tempered glass is fairly rigid and doesn’t conduct heat like metal, therefore it’s subject to what’s called thermal shock. If the glass is exposed to uneven temperature extremes, it will try to expand or contract  unevenly and can crack or shatter.

Some of you are sitting there going, gee Heather this is all common sense. Maybe for you it is.

A lot of people have only used metal cookware, which can warp, but doesn’t have that tendency to shatter. Since this is Home Ec 101, I try to cover all the basics. Heck, I remember shortly after I graduated high school one of my roommates attempting to make macaroni and cheese in one of my glass dishes, on the stove top. It didn’t go as she planned. To be fair, I did more than my fair share of stupid things in that phase of my life.

Glass is fragile¹.

It’s like it’s made of glass or something. . .

Do not use cracked glass bakeware. Do not bang metal utensils on the edge, do not juggle your cookware, drop it on the floor, and expect it to be good as new. Glass doesn’t heal.

Never use steel wool on glass bakeware. -Thanks Mike!

Got it?

To avoid breaking your glass cookware through thermal shock:

Never pour boiling liquids into cold or room temperature glass cookware.

Never pour cold liquids into hot glassware. This includes, trying to rinse the item out. (You also shouldn’t do this to cast iron or stainless steel, either).

Don’t immerse hot pans in cold water.

Never take a glass casserole directly from the freezer and place it into a pre-heated oven.

Do not take a glass dish straight from the oven and place it on a granite counter top. Use a hot pad to protect the dish.

Never heat a glass dish directly on a stove burner.

Don’t place glass cookware on a cold, wet towel. Use dry hot pads, cloths, or towels.

Finally, cut yourself some slack we all screw up. Sometimes we don’t see the puddle of water on the counter or act without thinking. A broken dish is a pain, but not the end of the world. If your glassware breaks after cooking. Do NOT serve or eat the food it contains. Broken glass fragments can be tiny and hard to see, it’s just not worth the risk.

¹Ever notice how words can appear misspelled when you look at them too closely? Fragile, just looks bizarre to me.

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24 thoughts on “Common Sense and Glass Cookware”

  1. We once had a large Pyrex baking dish full of lasagna explode in the oven. We discovered that 2 days before my obsessive-compulsive, clean freak mother-in-law had scrubbed the dish with a Brillo pad because she didn't think it was clean enough. That was enough to score the surface of the glass and destroy its integrity. Never use steel wool on Pyrex.

  2. This is one mishap that has not happen to me yet. I love my Pyrex and will take these precautions in to consideration and maybe even avoid these mishaps for a while… I am still trying to live down the two oven fires.

  3. I will always remember never put cold things in glass dishes that came straight of the dishwasher. We were in a restaurant where they put the ice cream in a freshly washed dish and it fell apart at the table.
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  4. I bought a big new set of Pyrex at the Black Friday sale at Target and was a bit surprised by all these warnings they post in the box. I've never used it much before, but will certainly use these precautions! I especially need to remember not to place them directly from the oven on the countertop – that's one area where we can get lazy because we often put hot pans directly on the granite – not the best idea I'm sure, but we don't have trivets like we used to 🙂

  5. How *do* you recommend cleaning pyrex baking dishes? I've never used steel wool/brillo, but I do have one with sauce remnants that burned a bit at the edges. Thanks!

    • First, try to prevent that by greasing the dish well before filling it — that can help it to come clean more easily, but it'll still happen somewhat.

      This is what I do: once cool, fill dish with hot water & dishwashing liquid – make it really soapy though, more so than if you were just washing up glasses & plates. Let it sit a while, maybe half an hour. Then I take a plastic scraper like the ones Pampered Chef has for cleaning their stoneware, and gently scrape the burned areas with that.

      My scraper is not actually from pampered chef – it's a green one I picked up at a yard sale for a nickel. Before that, I would use an expired credit card. Those aren't generally so stiff as the scrapers, but it worked surprisingly well.

    • In terms of cleaning pyrex, do you think it's safe to sprinkle baking soda and dish soap and clean with a Dobie sponge or lemon half? Thank you!

  6. It's not your Gramma's Pyrex. Not anymore.

    You know, it used to be perfectly fine to take Pyrex dishes from the freezer and put them right into an oven – they even advertised it as such. Freezer to Oven to Table, all in the same attractive dish. That stuff was made of the same borosilicate glass as the beakers, flasks, test tubes, etc., made for use in laboratories. If you took care while cleaning, you were good to go.

    But they went and changed the formula to a cheaper to make one that has a higher thermal expansion coefficient than borosilicate glass, and the FAILED to make a concurrent change in the way the public perceives Pyrex. This kind of thing really, really ticks me off, and as much as I want the government to stay the heck out of our lives, it's business practices like this that make it unavoidable. I'll stop now before I really start ranting.

    Fra GEE lay! (It's a major award!)

    • I don't know, I think it might be one of those things where the exceptions seem more remarkable than they are. I haven't had one break other than when my friend used it improperly.
      Also people like to use dramatic language like explode, when shatter is the better term. Once the term explode is used, it gets some attention.
      European Pyrex is still borosilicate glass, to my knowledge. In America I believe Pyrex changed to tempered soda lime in the 40s. Which means my grandmother had the same kind of Pyrex I use (if she even used Pyrex, she died before I was old enough to pay attention to that stuff)
      Oh and as far as I know, the lab grade equipment is still borosilicate.
      I just did some googling and came up with this:
      Snopes (I know isn't the end all) actually has some decent info:

      • Just so you know, they did actually change. A visit to any vintage or antique store can show you that. Original Pyrex, that is actually made out of Pyrex (Corning’s trademark for borosilicate glass) is not the same pale greenish blue of today’s Pyrex. Borosilicate Glass that is untinted has a near colorless cast. You can spot the difference easily if you have two pieces next to each other. I know they were selling it in the 1980’s, because I bought a few pieces for my mother. It’s true that you can use soda-lime glass safely, but on breaking, it tends to shatter, where older pyrex tends to crack into a few pieces. I can’t say for anyone else, but I need less mechanical breakage strength, as I’m not throwing my Pyrex around. I want the heat resistance and low thermal expansion of actually Pyrex. World Kitchen also had stopped making original pyroceramic Corning Ware, though they recently reintroduced it. That’s the stuff you could use on the stovetop.

  7. Heather, regarding words look misspelled when you look at them too closely — I once drove myself crazy for a few days because I was convinced I was spelling "of" wrong. It's a freakin' two-letter word, and I just knew I was spelling it WRONG.

    • Oh I hate when that happens. I once turned in an essay in English with "ou" for "or" throughout the whole thing. That's what I get for taking French, I guess. I still sometimes do that one.

  8. I don't have a comment on the Pyrex, but Yes, I see words that I think are misspelled all the time. It drives me NUTS! And the more I look, the more I'm convinced it's misspelled. But spell checker never counts it as wrong.

  9. The public's image of Pyrex? Heh.. years ago at the Corning plant in NY they had a guy who took a Pyrex baking dish and alternately took a blowtorch to it and dunked it in ice water. I guess I'll take care of my old stuff and stay away from the new Pyrex.

    I also have a few of the "Vision" pots… glass pots and pans made to go directly on the stove. They're hard to clean and don't get much use as a result.

  10. This would have been a fantastic read before Thanksgiving. I created a SPECTACULAR explosion of Pyrex in our oven 30 minutes before we were supposed to eat! We were cooking turkey breasts in a Pyrex dish because of turkey tragedy 1. They were wrapped in foil and I had added liquid to the dish before placing it in the oven to help keep the turkey moist. Well, a half hour before we eat, I checked the meat and the liquid was gone. So I added some water straight from the tap. It was magnificent I tell you. Absolutely stunning. The Pyrex actually exploded all over my oven. Thankfully all of the other food was covered in foil, or we would have been eating out!

  11. This is really dumb but I'm going to ask it anyway.

    Is it only a granite countertop that you cannot place a hot dish on, or would that apply to all counters (concrete, corian, butcherblock, etc.)

    I'm really bad about taking things out of the oven and putting them on my countertop.

    • Play it safe and use a trivet.
      It's usually an issue with granite, since most people would us a hotpad to protect their counters from the hot pan.

      That said, it's not really an issue with butcher block.

  12. Hi, can you put glass dishes/glass bakeware (pyrex, anchor brand) in a stovetop steamer (i.e. on top of a bakset steamer)?

    Also, what about baking in a waterbath in the oven (ie putting the glass dish inside a ceramic dish surrounded by hot water and then covered with foil)?

    Very specific, but I wanted to be sure. Thanks!


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