My oven is a smallish electric oven and if it's not preheated it might never get up to 425 with food in it. I've tossed a sheet pan of potatoes in before and between the temp of the food and the steam it lets off, it just hovers around 375. Doesn't get the food crispy or browned well at all. We got a Breville convection oven to avoid this issue and heating up the entire oven for one side dish in the summer.
If you're doing something like a braise or stew in the oven that will take a while, preheating the oven is pointless. Also, if you're bringing something from the refrigerator that is in glass or ceramic, you should start with a cold oven. Ask me how I know.
When I roast a chicken I put my cast iron skillet in there while it heats up to 425. That's been the best and most consistent way to cook one that I've found.
Most ovens preheat at a high temp so cooking something temp sensitive during preheat can alter results pretty dramatically. Once temp is reached, the slow, smooth heat output is what's desired for most baking. On the opposite end of the spectrum, some items need a blast of high heat at the onset to properly rise or cook off moisture. A preheated oven is a good way to accomplish that.
Simply reheating your pizza rolls or trying to crisp your Ore Ida tots is one thing but actual cooking of real food in an oven does stand to benefit from a decent preheat.
Most ovens preheat at a high temp so cooking something temp sensitive during preheat can alter results pretty dramatically. Once temp is reached, the slow, smooth heat output is what's desired for most baking. On the opposite end of the spectrum, some items need a blast of high heat at the onset to properly rise or cook off moisture. A preheated oven is a good way to accomplish that.
Simply reheating your pizza rolls or trying to crisp your Ore Ida tots is one thing but actual cooking of real food in an oven does stand to benefit from a decent preheat.
This. It might not matter for some foods, but most foods will benefit from a more even heat maintenance, than a blast of heat for X number of minutes till it reaches a stable temperature.
America's test kitchen did a video about this recently as well. See below .
