If I were to rank famous opening lines, “preheat oven to 350 degrees” would beat out any Shakespeare by a long shot. It’s a short, sweet, and downright iconic, as it's been kicking off American recipes for everything from apple pie to beef bourguignon for decades.
The phrase is so ubiquitous that many of us never stop to consider what exactly it means, why it’s there to begin with, and whether we need to follow its directions at all.
Whether you’re guilty of skipping the preheat step or you’re disappointed with your bakes despite following directions, read on to learn what you should be doing and why.
Does preheating really matter?
The short answer? For most foods, yes.
I know the last thing you want to do when you’re trying to put together an hour-long dinner is wait around 10 to 15 minutes for the oven to preheat. I feel your pain. But this little line is included in so many recipes because it actually does make a difference in how certain foods cook.
A good rule of thumb that if what you’re baking has flour or eggs, or if it cooks quickly like chicken, preheating is important. For example, ovens need to be to temperature when baking bread in order for the yeast to raise the loaf to its maximum height before the flour sets.
If you toss the pan in just as the oven is turned on, odds are you’re going to have a flat loaf. Lower temperatures simply won’t set off the proper reactions at the proper time in cookies, pastries, and cakes.
Some of us are guilty of skipping the preheat for foods we just don’t care about as much, such as frozen pizzas. You can do whatever you want with your weeknight food, but Reviewed still recommends preheating if you want anything close to a crispy crust on frozen pizzas and its ilk.
There is some good news for the lazy and tired home chefs among us, though. Preheating the oven isn’t essential for wet or slow-bake foods like casseroles and macaroni and cheese, because the gradual temperature change won’t have an effect on how they cook. If all that matters is that these foods cook, and they don’t require any fancy or delicate reactions to get there, skipping the preheat is entirely fair game.
Try it next time you need to toast nuts for a salad, roast a big piece of meat, or bake a veggie lasagna for a party and revel in the guilt-free ease of it all. Make sure to adjust the cook time by a few extra minutes, though.
So, why 350?
Of course, not every recipe calls for the 350-degree preheat—some casseroles and wet bakes will call for lower temperatures, while pizza needs to placed in the hottest oven possible to get a perfectly crispy crust. But 350 still seems like some kind of magical number between the the two extremes that pops up everywhere.
The truth is, 350 isn’t magic—it’s just an average. Over the years, chefs and scientists have found 350 to be the most accurate mid-point for baking things without drying their interiors or burning their exteriors.
While low and slow baking at temperatures below 300 degrees fahrenheit will cook things all the way through and prevent burning, this method risks drying out everything from cake to chicken parmesan. Baking at low temperatures will also make the Maillard reaction—the browning process that gives toast its color and complex flavor—occur more slowly, meaning your food might look anemic coming out of the oven.
On the other end, while baking things at temperatures over 400 degrees fahrenheit might be fast and give you crunchy, browned exteriors, the risk for burning the exterior without cooking the interior is high. Thus, 350 is the “magic” (scientific) solution, a compromise between tender interiors and Maillard-blessed exteriors.
350 is just a standardization of the tricky, finicky science of baking. A recipe for cookies on the back of a bag of chocolate chips might call for a 350-degree preheat, but factors including where you live, what type of oven you’re using, and how long you’ve chilled your dough could all affect how “good” this recommendation is—325 or 375 might better suit you.
Understanding a bit about the science of baking and how these factors affect bake time is the best way to arm yourself against bad bakes.
Preheating right but food still wrong? Invest in an oven thermometer
Even if you’re an incredibly type-A person who follows directions to a T and has no interest in kitchen experimentation, there’s a chance your bakes are coming out poorly. If things are consistently overcooked or underdone, your oven’s internal thermometer could be inaccurate.
The solution? Purchasing an extra oven thermometer that hangs on one of the racks and gives you the most accurate possible estimate of how hot it actually is inside your oven. Reviewed’s top choice, the Admetior Kitchen Thermometer, is available for $15 on Amazon.
Most ovens work by cycling between two different temperatures, a minimum and a maximum, and the temperature you set on the dial is just the average of those two temperatures—so don’t be alarmed if your extra thermometer seems to have different readings at different times.
To determine if your oven dial isn’t actually setting the temperature you want, take multiple readings over the course of a few hours and calculate the average. From there you can have your oven repaired, adjust the dial yourself, or let your knowledge of the discrepancy guide how you bake in the future.
Does the broiler hack work?
I’ve read multiple sources claim that setting your oven to “broil” rather than “bake” or “preheat” will make for a quicker preheat. While this “hack” might make your oven ding and let you know it’s at temperature a bit earlier, it’s likely you’re actually just tricking your oven into thinking it’s ready before it actually is.
Because the broil setting activates intense heat from the top of your oven, and most internal thermometers are placed within the upper half of the appliance, your oven might think it’s reached your desired temperature before that temperature is even throughout the entire appliance. And because consistent temperature throughout your oven is critical for most baked goods, this hack could actually hurt your baking instead of speeding it along.
Don’t believe me? You can test this at home yourself with your own oven thermometer.
When I tested the hack on Reviewed’s own electric ovens, setting them to broil for five minutes before switching to “bake” had a negligible effect on preheat speed altogether, while my gas oven at home did ding as though it were ready much faster after I had set to broil.
Gas ovens generally heat up quicker than electric ones, so if you’re a regular baker who is extremely pressed for time, your best bet is to invest in a gas oven and preheat as normal. You might think you can out-smart oven manufacturers, but you probably can’t.
Don’t be Carrie Bradshaw
My last bit of advice? Don’t store clothes in your unused oven like Carrie Bradshaw. God forbid you, your partner, or your child clicks “preheat” without opening up first and starts a fire. Even then, it’s always good to open up the oven to make sure no old dishes were forgotten there and to adjust the rack to the right height before you bake.
Now, on your marks, get set, bake!