Unless you're a serious baker or chef, you may have wondered at some point whether pre-heating your oven is actually necessary -- especially when you're in a rush to get food on the table. Well, it is. Here are a couple of reasons why. Photo by Mark Skipper.
To the untrained eye, pre-heating an oven can seem like a waste of time and energy. Those chocolate chip cookies will bake eventually, right? So why not just put them in as soon as you turn on your oven? Alice Medrich at Food52 explains why:
Time and temperature affect the texture and flavour of baked goods, and starting in a cold oven changes both of those variables.... The fine crumb or flakey, layered texture of cookies, cakes and pie crusts comes the expansion of trapped air and/or moisture in these batters and doughs (along with chemical leaveners such as baking soda or powder or yeast). And that expansion is produced by heat. Many batters and doughs require a push -- a good hit of heat at the beginning -- for optimal rise, texture, and browning (and remember browning is flavour)...
When you give your baked goods a cold start, cookies will turn out hard and dry, pastries will be pale and crunchy (not flaky), pizza crust won't be crispy and chewy and cakes will have a weird, tough layer at the bottom. Besides, sticking baked goods in the oven while it's preheating only extends cooking times, so you're not actually saving time or energy anyway. Some recipes do, however, call for cold starts, but they will be very explicit about that in the instructions. So, no matter how much of a rush you're in, preheating is essential.