Warning: exploding Pyrex

I used to use a pyrex water dish for quenching small pieces until one exploded on my bench from thermal shock, which I figured was my fault because it was placed in proximity to my small kiln. I replaced it with a small stainless steel water dish. A few days ago I was making a salad in a large pyrex bowl. It was filled with salad stuff that I was slicing inside the bowl with a fragile ceramic knife. All of a sudden it exploded, spewing glass shards and salad everywhere. The large pieces were not sharp, but there were tiny microscopic shards everywhere in the kitchen. I had a couple of tiny cuts and I was so, so grateful that I was wearing glasses. I researched “exploding pyrex” online and learned that this is rare, but it happens. The large pyrex bowl likely had a tiny invisible fracture that the ceramic knife touched in just the wrong way. Please replace your pyrex with ceramic or stainless when you are drilling glass/stones or quenching small pieces. You don’t need tempered glass exploding in your face. There are enough hazards on the bench as it is.


Hi makena,
ok, wow! i need to find metal loaf pans to replace my pyrex!


This is not a new thing. Do a web search on “exploding Pyrex”. It has made the news some years ago. Pyrex used to be made of borosilicate glass that doesn’t do those things. It no longer is in the U.S., but still is in Europe. Ask the company why.

Pyrex items should be replaced with other materials. Perhaps Corelle ceramic.

Neil A


Check this out: Why We’re Not Worried About Pyrex Bakeware “Exploding” | Wirecutter

Makena, in your case, the Pyrex didnt need to be flawed. Your mistake was using a ceramic knife to cut on Pyrex. The ceramic the blade is made of is considerably harder than the glass, and it’s sharp edge/point acted like a very effective glass cutter. The glass has a certain amount of internal stress built in, to make it stronger, but when you put that very slim scratch into the glass with that knife, the pre-stressed glass shattered. Many types of glass would have done the same. If you must cut on a glass surface,use an ordinary steel knife. Not a very sharp one. Or for salads, there are plastic knives. Or use scissors. But considering the cost of a good ceramic knife, it would usually pay to take care of it, since once dulled by mistreatment, home sharpening equipment won’t resharpen it. Cut on wood or plastic cutting boards. Not steel, not glass. The same holds true of any fine knives.


Thank you for your reply Peter, that explains a lot. It was shocking at the time because I have been using glass bowls for slicing up salads for more than 20 years with no incidents, but most of them were just regular glass. This was a bowl that I inherited and hadn’t used before, but in the past it was no doubt heavily used. The ceramic knife in question was not at all sharp; it was quite dull from the time I bought it (on sale; not top of the line). Advice taken: only wood salad bowls going forward. On the bench: stainless steel.

I did do a web search, as I mentioned in my original post. I also urged people not to use it on the bench.

I do not understand why you say pyrex is longer in the US, but it clearly is according to amazon.com Amazon.com

I do not understand why you say pyrex is longer in the US, but it clearly is according to amazon.

What I said was that borosylicate Pyrex is not made here any more. If you will read the description on Amazon you will see it is made of tempered glass. Not the same thing.


The Wikipedia entry on Pyrex has more info.

“Corelle Brands continues to license the pyrex (all lowercase) trademark for their tempered soda-lime glass line of kitchenware products sold in the United States, South America, and Asia. In Europe, Africa, and the Middle East, the PYREX (all uppercase) trademark is licensed by International Cookware for their borosilicate glass products.”

Add a trench coat or two and it could become the plot of a spy novel.

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Using a ceramic knife, sharp or not, is a mistake on anything other than a cutting board. Any broken edge of the knife is way harder than glass. Ceramic knives break when wedged or dropped and are not usually sharpened in the kitchen. Ceramic knives have a place and I used them exclusively for years. Now I only use good steel knives that i can sharpen. Sometimes old style tools are best.
j hoch

It is certainly too expensive nowadays to make a kitchen set out of borosilicate glass. I’d bet that the average home cook doesn’t cook to the extremes like home cooks did 30-40 years ago. :wink:

I use a stainless steel saucepan fro the second hand shop for a quenching bowl. The handle is handy and its almost indestructible.