Is preheating the oven necessary?

Almost every baking recipe begins with the words “Preheat the oven to NNN degrees,” but is it really necessary to go through that step? Wouldn’t it be more energy efficient to just put your food items in while the oven is heating? The answers to those questions depend on what you are making, says cookbook author Alice Zaslavsky. She explains the ins and outs of when it makes sense to preheat and when it might not work.

Many foods benefit from an initial blast of heat from an already hot oven. Rustic breads, roast potatoes, and most any egg-based dishes like souffle and quiche use the initial high heat to trap air or create a crunchy crust on the foods. Most cakes and cookies plus delicate vegetables require an even heat and therefore shouldn’t be started in a cold oven (with an exception for the famous cold oven pound cake). Zaslavsky thinks that roast meat and poultry require the precision of having the oven at a set temp, although I might disagree with her on this one.

Other items are less fussy and can be started in a cold oven: root vegetables, anything you are reheating, things cooked in liquid like braises, and most frozen foods don’t need the oven to be hot before you throw them in. You can save time and energy by putting these foods in right away without waiting for the oven to come to temperature.

Finally, as Zaslavsky says, “Taking the time to get to know your oven will pay dividends because you’ll know how much leeway you have for the recipes when preheating matters less, and how much time you have to prep and potter where it’s still a non-negotiable.” Through trial and error you can evaluate what works best for your oven. I previously had an oven that used a powerful broiler element to speed up the preheat cycle, and if I chucked a frozen pizza into the oven before turning it on, the cheese would be scorched before the bottom was even thawed (ask me how I know). This isn’t an issue in my current oven which seems to be programmed to only use the bottom element for the preheat. As with all advice, you should view a proclamation about whether to preheat your oven as an opinion and not as gospel.