Tempered glassbakeware has been in the American marketplace since before World War I, when the Corning company launched its Pyrex brand. Glass cookware and bakeware are versatile, but do require a few adjustments to cooking methods and temperatures.
Its biggest advantage is that the contents of the pot can be seen at all times, making it easier to monitor the food as it cooks. On the other hand, glass cookware tends to retain heat and allow foods to cook on and stick to the pot.
Square, rectangular and round cake pans, oval roasters, pie plates, and casserole dishes are all available from a variety of glassbakeware manufacturers. The baker can tell at a glance how well a pie crust or cake is browning, and can adjust the temperature or rack placement accordingly.
In most cases, bakers must reduce oven temperatures by 25 degrees Fahrenheit to avoid excessive browning in glass pans. Avoid sudden temperature changes, and always rest the hot pans on a dry towel or cork trivet to cool.
I have also heard that glass will get hotter than metal, and thus I should cook it at a lower temperature for longer. There's a lot of erroneous information circulating concerning glassbakeware, and very few reliable sources or repeatable experiments seem to be cited.
So, if you're someone who worries a lot about pan color or thickness and adjusts your oven up or down by a few degrees for it already, then yes, this may be a concern. If you're someone who just assumes all metal baking pans are equivalent anyway, glass is not going to behave much differently -- I'd just say monitor your food when trying a new pan/dish, and adjust your time and temperature accordingly.
But this is mostly relevant when the pan is changing temperature (as when first put in the oven) or heated unevenly. Glass therefore heats up and cools down more slowly, so it will be less responsive to changes in baking temperatures.
Each of these factors may be more or less relevant depending on your specific baking situation and recipe. But if you're baking a dish for a long time, this factor is less relevant, and the extra heat which is transmitted through the clear glass may actually cause food to cook faster.
Harold McGee in On Food and Cooking seems at one point to lump glass together with light-colored dull metal pans in terms of overall baking properties, pointing out that both will transmit heat better than shiny metal pans and thus will cook (about 20%) faster. But dark-colored or black pans will increase browning and cooking even more.
I recall seeing a Cooks Illustrated test some time ago that basically claimed the oven temperature reduction for glass was generally unnecessary, but I don't recall the details (and can't find the reference now). In terms of actual empirical data, well, there's this source on browning, which baked dough for 15 minutes in four dishes of the same size but different colors and materials.
Glass here performed slower than a black pan or thin (shiny) aluminum, but faster than white ceramic. If baking for a short time (say, less than 20-30 minutes), the lag-time in glass warming up will be significant.
Cooking may be somewhat slower for food in contact with the glass surface compared to a metal pan. In that case, you may want to make small adjustments in the same way as you might for different colored metal baking pans.
The one nice thing about glass baking dishes is that you can view the food from many more angles, which can often give you information about how fast the dish is cooking on the bottom as well as the top -- and you can adjust oven temperature as needed to try to even things out. The long answer above makes some good points, regarding light and dark metal, but I want to address what goes into the pan.
The sugar in the recipe acts like a liquid as the brownies bake, migrating toward the edges. I would add another dimension along which the pan types might differ significantly, which would be how evenly they cook the top versus the sides and bottom.
Today, pampered chefs can choose between metal and glass pans, as well as newer silicon bakeware. When following a recipe or instructions on a box, it is important to adjust the recommended baking time in order to prevent your food from burning.
Food also tends to bake more evenly in glass pans, browning rather than burning. The darker the metal, the more heat your pan will absorb, and the faster your food will bake.
This will prevent the bottom and edges of your brownies or cake from becoming charred and crunchy. Most boxed dessert kits instruct that you should preheat the oven at a lower temperature when using a dark or nonstick pan; glass or darker, nonstick metal pans should be heated to a slightly lower temperature, usually about 25 degrees F difference.
If you are using lighter metal pans without a coating or insulation, do not adjust the recipe or temperature. Every editorial product is independently selected, though we may be compensated or receive an affiliate commission if you buy something through our links.
It also retains heat better than metal bakeware, which is great if you want your casserole to stay warm at the table or on the buffet. If you have a recipe that calls for a metal baking pan and you have to substitute glass, you usually need to decrease the oven temperature by 25 degrees.
There are some care tips you need to consider with glassbakeware : Never heat glass on the stove top or under the broiler or it can shatter. Our Test Kitchen likes to cook pies and quick breads in glass dishes.
Recommended GlassBakeware via amazon.com Pyrex Glass Baking Dish Shop Now It also retains heat well, so your lasagna will stay bubbly hot on the dinner table.
Ceramic dishes come in a wide array of colors and patterns which can be a real highlight on the dinner table. Like glass, ceramic bakeware is sensitive to extreme temperature changes, so don’t place that hot dish in a cold water bath.
Recommended Ceramic Bakeware via target.com Threshold Baking Dishes Shop Now This means your food will have a more browned color and crispy edges.
Keep in mind that aluminum or steel reacts with acidic foods, so stick to glass and ceramic when baking with tomatoes or citrus. Dark metal pans will bake whatever is inside a more quickly.
When to use it : Choose metal for baked goods like bread, bars or brownies to give them the golden brown edges and bottoms you expect. Metal is also a good pick for dishes like meat loaf where you want the exterior to have a browned quality.
Our Test Kitchen likes to use metal pans for cakes and cookies. Now that you know the differences between metal, glass and ceramic bakeware, you might find yourself grabbing a few of each (it never hurts to have a well-stocked kitchen).
Considering these warnings, I feel pretty good about my decision to hold off on the cold glass /hot pan scenario. Yes, the eyes are heat-resistant, but as indicated above, placing hot glass on cool metal could result in shattering.
The point here is to avoid subjecting the hot glass to cool liquids, such as juices that might seep out of foods while cooking. Starting the cooking process with some liquid already in the pan will prevent cool or room temperature juices from having a negative impact.
For one thing, wet cloths and oven mitts conduct heat, so you'll burn your hands. What might surprise you is that your results can be dramatically different, depending on whether you've baked your recipe in a glass or metal pan.
Learners are activated, things rise and are eventually set in their finished form, all while the kitchen smells heavenly. At the same time, it's easier to over-bake brownies in a glass pan, because it takes longer for the center to cook.
By the time the center finishes, the glass is acting like a heat sink, and the outer edges of your brownies are getting very tall and probably pretty hard. It's non-reactive, which means it won't corrode from the acid in your lemon cake, or change the flavor of anything you bake in it.
And once glass heats up, it will do a good job of making sure bottom crusts get crisp and golden. Hand-thrown pie plates will bake differently than a stoneware pan made from liquid slip poured into a mold.
The amount of minerals and metals in the clay itself also determines the rate at which heat can move through the pan. Brownie lineup, left to right: corner pieces baked in metal, stoneware, and glass.
The stoneware pans' sides are slightly sloped, and the dimensions are more like 8 1/2” square, so the batter is spread a little thinner. It's interesting to note that the dome of the glass -baked cake is the lowest; that's a function of slower heat transfer.
I expected the glass slice to have the darkest, thickest crust, but the reverse is true. On further reflection, I realize the insulating properties of the glass protect the bottom edge to a degree.
The metal and stoneware pans have darker edges; as the heat moves through the batter, it helps the tops get higher, but the sugar and fat in the formula cook more efficiently (and get darker) where they're in contact with the pans. Glass pans' dimensions can be all over the place (try taking a measuring tape to the store next time you shop; you might be surprised).
Stoneware composition varies too much to rely on for testing (different levels of conductivity and sizes are often not exact). The hard edges we see here are more pronounced in high-sugar, high-fat recipes; your casserole or bread pudding are less likely to be adversely affected.
Stoneware just takes some getting to know; once you learn how your pan bakes, you can make any adjustments that work for you. About Susan Reid Chef Susan Reid grew up in New Jersey, graduated from Bates College and the Culinary Institute of America, and is presently the Food Editor of Sift magazine.