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Are there any problems with using glass bakeware?

Glass cook- and bake-ware is durable, inert, affordable and saves energy. Pyrex and Corning both make tempered glass cookware.

The downside to glass is that there have been many recent reports of both Pyrex and Visions shattering in the oven and stovetop. It may be that newer pieces are made differently. I personally have not had this problem, but all of my Pyrex and Visions are more than ten years old. Some of my Pyrex I inherited from my grandmothers.

From a cooking viewpoint, glass is ideal. But there apparently are some safety issues.


The most popular glass cookware and bakeware is Pyrex, which has been in use for almost a century. Made by Corning Glass Works, the "low-expansion" glass was originally developed in response to a request from the railroads to produce lantern glass that would not break when the hot glass was struck by rain or snow. The super-tough "fire glass" was not only resistant to temperature fluctuations, but also chemical corrosion and breakage as well.

In 1913, the wife of one of Corning's scientists used a new casserole dish only twice before it fractured in the oven. Having heard about the glass her husband worked with, she asked him to bring home a fire-glass container she could use for baking. She baked a sponge cake and found the cooking time was shorter, the cake did not stick to the glass, the baking was unusually uniform, the flavor of the cake did not remain in the dish after washing, and she could watch the cake bake and know it was done by looking at the underside. These features have made Pyrex glass a favorite among home cooks.

According to their website, silica (a compound found in quartz and sand) is the main ingredient. "Eight ingredients are added and some broken glass" and all are cooked in a huge furnace at 3,000 degrees Fahrenheit. So while it doesn't contain recycled glass bottles, broken glass within the factory is recycled back into the pot. Pyrex is durable (so it can be reused for years without breaking or chipping) and it saves energy (Pyrex glass absorbs, rather than reflecting oven heat waves, thereby reducing cooking time over earthenware, porcelain or enameled dishes).

  • Pyrex is completely inert and does not leach anything into the food being cooked, you can bake and serve in the same dish, and then put it in the refrigerator and freezer.
  • Pyrex is affordable, comes in many sizes and shapes, and is sold everywhere.

Corning also makes tempered-glass Visions pots (made from a proprietary blend of glass and ceramic). Corning Visions is sold on the internet and is available used on eBay and can often be found in thrift stores and flea markets.

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