For an act as seemingly simple as roasting vegetables (we even told you you could it without a recipe!), there sure are a lot of ways to go about it.
But is there one way that's better than the others? To find out, I surveyed trusted sources, then conducted my own miniature experiment, which—spoiler alert—convinced me to steer clear of temperatures below 400° F for most roasting endeavors.
First, the conventional wisdom. Our article recommends an oven between 400° and 450° F, and our Test Kitchen Manager Josh Cohen takes the temperature higher: "I think of (most) vegetable cooking as a race against time, where the goal is to get as much caramelization as possible before the vegetable turns too soft: maximum caramelization with an al dente texture."
Even the team at Food52 is split over the roasting temperature; when I polled my co-workers for their go-to heat, answers ranged from 325° to 425° F.
Sources beyond Food52 provide information that's just as mixed.
The oven-roasted parsnips from the Gjelina cookbook start in a hot sauté pan for 5 minutes, then move to a 500° F (!) oven, where they're roasted for 15 minutes, then finally returned to the stovetop over high heat for another 5 minutes. As the author explains:
"We start by browning the parsnips on the stove top, and then move them to the oven to ensure a deeply caramelized exterior with crispy edges. Then we rock them on the stove top again at the end to ensure they are as crisp as possible."
The Cook's Illustrated recipe for Perfect Roasted Roots has you preheat the baking sheet in a 425° F oven, then transfer the vegetables to the hot sheet, and cook for 40 to 50 minutes.
And then, on the other end of the spectrum, there's this article from Bon Appétit, which admonishes us to "Stop Cooking [...] Vegetables in a Screaming-Hot Oven." Instead, roast them...
in a 250° F oven until the exterior gets all shrivel-y and the interior takes on a delicate, custard-like texture. This is less about adding brash browned notes than it is concentrating natural flavors, yielding vegetables that taste distinctly and deliciously of themselves.
To get to the bottom of things, I conducted a simple, not-so-scientific experiment. I roughly chopped three different vegetables—carrots, cauliflower, and potatoes—tossed them with a bit of olive oil, salt, and pepper, and roasted them at three different temperatures:
- Low and slow: 250° F for 55 minutes (as Bon Appétit recommends)
- Limbo: 350° F for 35 minutes (Josh calls this oven no man's land, "halfway between the slow technique and the caramelization of high heat")
- Fast and furious: 450° F for 20 minutes (for caramelized outside bits and a still-firm texture)
The photos below show the vegetables roasted at 250°, 350°, and 450° F respectively. You will notice that...
- Caramelization happens at every temperature (even 250° F!) but the high-heat veg are definitely the most burnished
- The vegetables roasted at 350° F appear more raw (less shriveled, less uniformly brown) than those cooked at a lower heat for a longer amount of time
The potatoes roasted on high heat were by far the best. After just 20 minutes in a 450° F oven, they had taut, golden-brown skins and soft insides. The low-heat potatoes were the worst: They had a soft outer skin but were raw on the inside (they're "actually crunching," said Kristen). The potatoes cooked at 350° F were not raw (phew) but they were less flavorful than their high-heat counterparts, with no delicious brown bits.
The high heat won here, too. The cauliflower roasted at 450° F for 20 minutes was the most flavorful and not at all mushy. The batch roasted at 350° F was sweeter but also mushier. The low-temp cauliflower was also soft (just as tender, if not more so, than the 350° F vegetables) but with a raw taste (no natural concentrated flavor—at least not yet).
Here, our winner was a little more ambiguous (perhaps because the carrots were not precisely chopped). As you can see from the photo below, the differences in appearance were negligible. In taste, the low-heat carrots were the losers, with a raw taste despite the soft texture. Those cooked at medium and high heat were hard to distinguish: Both were tender, but the 350° F carrots were the slightest bit sweeter.
While our vegetables varied in size and character (roasting 1/2-inch potato cubes is obviously different than roasting 1/2-inch bits of carrot), the side-by-side test revealed a basic roasting principle.
For most roasting needs, 350° F is, indeed, no man's land. While it provided edible results for all three vegetables, it never won the taste-test. All of the vegetables roasted at 350° F had the potential to be better-tasting (whether that meant more caramelized or less raw-tasting). The vegetables cooked at 250° F seemed to have potential, but most had a rawness rather than a sweetness—even after 55 minutes. Yes, we could have roasted for longer (B.A. suggests checking after 60 to 90 minutes when roasting whole carrots), but it's not worth it for chopped vegetables.
Usually, you'll be good to go with temperatures above 400° F, but remember that similar logic applies to roasting as to frying: To cook the inside of the vegetable at the same rate as the outside of the vegetable (dehydrating the external and internal bits at the same rate for a pruney outside and butter-soft inside), you'll want to use a lower temperature for a longer amount of time.
So, think about your end goal:
- For crisp outside bits and a still-firm interior, you're aiming to brown the exterior of the vegetable before the inside has a chance to cook. In other words, you want high heat for a short amount of time. Take it to 500° F, but at your own risk: You might end up with burnt edges and raw insides.
- For vegetables that are soft through-and-through, go lower and slower. Who knows? Maybe you're looking for an even mushiness if you're planning to purée the vegetables into a soup.
- And for larger vegetables—baked potatoes, thick wedges or halves of squash, whole carrots—it doesn't make sense to use very high heat (over 450° F), as you'll end up cooking the outside before the inside is edible. In most cases, you can stick with 400° F and bake for a longer amount of time (as is the case with these acorn squash wedges), covering with foil to stave off rapid browning. If you want them crisp on the outsides, sear them on the stove before (or before and after, as they do at Gjelina!) roasting.
What's your default method for roasting vegetables? Tell us in the comments below!
This article originally appeared on February 24, 2016. We're re-running it now because, for us, it's the season of roasted vegetables.