Oatmeal Raisin Cookies Smoke While Cooking On A Heavy-duty Sheet
Q: I use two cookie sheets for baking the recipe. One is a Pyrex professional metal sheet. (If you google on "Pyrex Professional Large Flat Cookie Sheet", you'll see it in the second photo for amazon.com.) The other is a no-name non-stick sheet. Normal cooking time is 11 minutes at 375F. I use both sheets at once. Shortly before time is up, smoke comes from the oven. The raisins on the Pyrex sheet seem to be the cause. Oddly, the cookie bottoms are NOT burned (or even darker), and the cookies taste just as good as those on the other sheet. I tried reducing the temperature to 350 and cooking an extra minute. Still some smoke, but not as much. I grease both sheets with butter. Any ideas why the smoke for the heavy-duty Pyrex sheet, but not the other?
A: Glass cookware, nowadays, consists primarily of bakeware dishes in various shapes, liquid measuring cups, and mixing bowls, all made of borosilicate glass, the same kind used for laboratory ware. Corning Pyrex glass cookware can withstand severe temperature differentials, such as cold liquid on the inside and a direct flame on the outside. It is subject to chipping, scratching, and cracking, though. Such minor damage, if liquid works its way in and then is subject to rapid heating, can cause the glass to shatter. When this happens in the oven, it makes a mess, but at least nobody is hit by flying glass. Fear of such catastrophic failure on the stovetop may be the reason few, if any, ceramic glass cookware pots and pans are made anymore. Corning Ware glass cookware also includes tempered glass lids, widely available on the Corning lines of cookware as well as available separately. Glass appliance covers can be one solid piece or may be fitted with metal or metal and plastic handles as well as metal rims to guard against damage. Glass bakeware dishes behave differently from metal bakeware. Porcelain glass cookware heats up and cool down more slowly and help prevent a thick crust from forming on casseroles, brownies, and other foods. Generally, to adapt a recipe from a metal dish to a glass dish, you should lower the baking temperature by 25 degrees and allow a bit of extra time in the oven.