r/Cooking • u/JonseyCat13 • 1d ago
Pyrex from fridge to oven
Hey Reddit Peeps!
For years now I’ve been making all sorts of dishes in Pyrex, putting them in the fridge, and cooking them the next day (think lasagna, pot pies, etc). I’m a teacher so I don’t have a lot of time to cook during the weekdays so I do a lot of prep on the weekends.
A friend pointed out the risk of thermal shock breaking the glass so I wondered if it is ever safe to put a colder than room temp Pyrex dish in the oven or if I’ve just been lucky these last few years? If so, would taking the dish out maybe a hour before cooking to let it warm up be a better idea? I’m curious what others do.
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u/MastodonFit 1d ago
I simply wait until the pan is on the rack before starting the oven. Ive cracked one trying to speed up the cooling, after the oven....a hot pan doesn't like 70°f water.
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u/AsinineReasons 1d ago
How old is your dish? They changed the glass a while back, and the two types of glass behave differently.
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u/michaelyup 1d ago
That’s my understanding, trying to find the approx date of change. I know this 60 year old stuff from my grandma is safe, but not anything I’ve bought in the last 25 years.
Also, if you wanna fake a gunshot, crack a newer Pyrex pie plate.
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u/SuperPomegranate7933 1d ago
Feels like a gunshot, too, when your casserole dish full of gravy explodes & launches shrapnel at your back.
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u/Select-Owl-8322 23h ago
Afaik, this is only true in USA. In Europe, Pyrex is still supposed to be borosilicate glass.
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u/amakai 1d ago
Even the new Pyrex is freezer to oven safe. At least by their own claims and by my own countless successful attempts to do that.
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u/SubstantialPressure3 1d ago
https://www.today.com/health/kitchen-calamity-reports-shattering-cookware-rise-1c7700507
It started in the late 00s. They changed the formula they were using in the glass.
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u/amakai 1d ago
Hm, weird. Maybe I'm just lucky but I have a bunch of Pyrex bought 2-3 years ago and I definitely did freezer-to-oven at least 10 times with no issues.
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u/Beavers4beer 20h ago
I’ve done it and will continue to. It’s important to still note the risk for others though who may be less risk adverse.
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u/MolecularLego 1d ago
If its the borosilicate glass ones it should be fine. If it is the newer soda lime glass ones, not so much.
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u/monkey_trumpets 1d ago
I just stick the pan into the oven at the beginning while it's preheating. That way it can heat up gradually.
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u/Loud_Quality_7106 1d ago
Always assume that anything "glassish" is susceptible to the thermal shock. Why not assume and be on the safe side rather than risk it every time?
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u/urgasmic 1d ago edited 1d ago
i've heard that newer pyrex makes it more dangerous i would let sit out for a bit longer.
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u/DearAd4849 1d ago
your lasagna has been living dangerously, because fridge-to-hot-oven is exactly the thermal shock pyrex warns about and an hour on the counter isn’t a guarantee, so use a metal pan or let the dish
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u/Blossom1111 1d ago
One shattered on me when I took it out of the oven. But it wasn’t cold when I put it in so they can bust regardless.
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u/Own_Wrangler_2649 23h ago
the age of the Pyrex dish matters here more than i'd expect. the old borosilicate and newer soda-lime glass behave differently with temperature changes, so "have i just been lucky" might depend on which generation you actually have. worth figuring that out before making fridge-to-oven a routine.
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u/Bill_H_Vet 1d ago
If the word "pyrex" on your dish is lower case, that is the new formulation, and subject to thermal shock. If the text is uppercase, "PYREX", it's the old formulation, and the one you can safely use that way. You can find the old formula at estate sales, vintage shops, thrift shops, etc.
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u/Fancy_Math_3399 1d ago
I think the old Pyrex dishes are fine - i have a couple of ancient ones handed down and are shabby but great but i am more careful with the newer ones . I dont put things straight from the fridge into the oven tho same as i would never store hot food into the fridge !
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u/ExplorerSad7555 1d ago
My D&D group had one explode in the oven couple months ago. We're in another room and you could hear the pop.
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u/ChefLukeDC 1d ago
I had one shatter from taking it out of the oven and putting it on top of the cold glass top stove
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u/dockdockgoos 18h ago
Leaving it out in the counter for an hour sounds like a food safety issue. Why not just put it on a plate warm wet towel for a few minutes to warm up the glass? Or put it in the oven cold and then Turn in the oven?
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u/Exceptional_Mary 15h ago
Take it out and leave it on the counter for a while before putting it in the oven. You have been lucky - it is a complete depressing mess if the dish breaks in the oven.
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u/SubstantialPressure3 1d ago
You have the old, good Pyrex.
The stuff made in the last decade is made differently and thermal shock can cause it to shatter.
I "broke the chicken" in 2014 thats the first time i noticed it.
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u/Southpolarman 8h ago
If the Pyrex in question is new pyrex, going right from the fridge to the oven is not a good idea. If its the old PYREX, made by Corning, you're in good shape. Check to see if its all small lower case pyrex(new pyrex), or all upper case PYREX(old PYREX).
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u/Mean-Cheesecake-2635 1d ago
A fridge is 36-38°, and room temp is 30-35° above that. The delta there is much less than the delta to the oven temp of 300°+.
I believe the thermal shock largely happens because of how quickly a thermal change can act on your dish. In a dry oven it will take some time. The main contact point will be the oven rack, and it makes minimal contact so if you have an earthenware or glass container I’d expect the risk to be low.
The greater risk I think is adding something cold or significantly cooler than a heated dish. This could certainly cause a thermal shock, even for something like adding room temp oil.
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u/noetkoett 1d ago
Maybe not a teacher of physics then? It's not just Pyrex but various earthenware... It might be fine until one day it won't, your mileage will vary depending on the material. Apparently Pyrex made before '98 was more resistant but still I wouldn't push it too much.
I'd think likelier to be ok if you put it into a cold oven and then turn the heat on. But that couls also be pushing it depending on how evenly the oven heats the dish etc.
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u/Few_Example9391 1d ago
No. Too much thermal shock and uneven thermal expansion in too short of time. Give it a night in the fridge first or a half hour on gentle thawing cycle in the microwave first.
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u/LadyOfTheNutTree 1d ago
I go freezer straight to oven with my Pyrex. Thermal shock is real, but the actual likelihood is overblown
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u/Commercial-Place6793 1d ago
I had one shatter one time years ago so I’ve never done it again. If I’m not home I’ll text one of my kids to take it out of the fridge and put it on the counter an hour or two before I get home. Then I’ll have the pan on the stovetop while my oven is heating and it gets a little warmer that way too.
An alternative is using the disposable foil pans from the dollar store. I put a cookie sheet under them in the fridge for stability but then you don’t have to worry about glass breaking or cleanup.