Most standard recipes will begin with the step to preheat the oven. But what if you accidently skipped over that part? Are you patient enough to wait for the oven to get up to the proper temperature, or do you sneak the casserole in the cold oven and set the timer? My growling stomach has made me do the latter, and yet the casserole seemed to turn out just fine, which made me pose the question: Is it really necessary to preheat the oven?
Some foods don’t really mind being put in a cold oven, but other foods depend on that immediate heat. Temperature is part of the chemical reaction process for baked goods made with a leavening agent, such as baking powder. When baking powder is mixed in a batter or dough, carbon dioxide bubbles are produced, and unless you get it in a preheated oven quickly, the product won’t rise as it should. Yeast breads prefer a preheated oven, as well, which allows for a final “proofing” or rising. Putting it into a cold oven could make the bread dense, dry and crumbly.
Soufflés, egg dishes and meringues need a preheated oven. Otherwise, it will fall flat before it’s even cooked. It’s equally important not to open the oven door midway through, which lets heat out and inevitably sinks the dish.
While a preheated oven is necessary to produce a quality product for some foods, it’s really not going to make much difference in other dishes. Most vegetables, meats and casseroles don’t actually need a preheated oven. In general, those recipes that have a long, slow cooking time, such as a roast, will not require a preheated oven, but those recipes that have a quicker cooking time and higher oven temperature generally need a preheated oven. For instance, most pizza recipes instruct you to preheat the oven and cook at a temperature of 400 degrees or higher for a short period of time; this makes for a nice crispy crust.
So yes, you can get away with not preheating the oven for some dishes; they’ll simply be cooked at a lower temperature for the first 5-15 minutes, depending on the target temperature and the strength of your oven. Therefore, it will take longer to cook than what the recipe indicates. And if it takes longer to cook, energy really isn’t being saved. Best practice is to preheat the oven if the recipes says to preheat the oven!
Smith, a registered dietitian, is a nutrition and wellness educator for the University of Illinois Extension, McLean County. Contact her at 309-663-8306.