If you think the tales of exploding glass bakeware made by Pyrex and other manufacturers are just urban legends, they're not. The January issue of Consumer Reports (full article only available to subscribers) investigates the phenomenon, recapping documented cases, like this one: "According to legal documents filed in a federal court in fall 2008, Sharon Fluker of Shreveport, La., opened her oven and started basting a rib roast baking 350 degrees in an Anchor Hocking baking dish in Oct. 2007, and the dish exploded while she was bent over it. Glass shards flew across the kitchen, including 'multiple large glass fragments,' and hundreds of 'microscopic shards penetrated her face and eyes, causing serious injury and loss of vision.'"
Yes, shards in the eyes. In fact, Consumer Reports was concerned enough about what it calls "scores" of cases of reported explosions, the injuries received, and the circumstances in which these explosions were taking place (i.e., consumers using the product as directed) that it devoted five pages to the issue. The problem, it seems, is relatively recent. Glass bakeware sold in the U.S. used to be made of tough borosilicate. It's now made of soda lime glass, described in a Corning educational booklet from 1984 (quoted in Consumer Reports) as "the lowest in cost of all glasses" and that its "resistance to high temperatures and sudden changes of temperature are not good."
CR examined 163 incidents in detail and found that in three-quarters, the bakeware was being used at 375 degrees or less, and about half exploded while in the oven. Yikes, that leaves another half out where they can send glass shards flying into your eyes. How to avoid this? Consumer Reports had a whole lot of recommendations:
* Put hot glassware on a dry cloth potholder or towel to cool
* Do not use glassware under a broiler or on a stovetop
* Let your oven fully preheat before putting glassware in it
* If you're cooking meat or vegetables in glassware, cover the bottom with liquid
* If the glassware is hot, do not add liquid (basting is out, people)
* Do not overheat butter or oil in glassware or the microwave
* Don't put dishes from the oven into the freezer and vice versa
* Hot glassware should not be put on metal of any kind, stovetops, in the sink, on countertops, or on any damp or wet surface
* Dishes with chips or cracks, even small ones, are more vulnerable
* Consider using metal bakeware in the oven
Yeah, it's that last one that really made me chuckle ruefully. My cast iron pan is looking better and better. It weighs 700 pounds, but it can go from stovetop to oven to fridge with nary a shard.