How to Boil Corn: Our Tests Reveal It's Not What Anyone Tells You

Everyone has their method for boiling "perfect" ears of sweet corn. My in-laws have sworn for years that the best method is to drop the corn into a pot of boiling water, return it to a boil, then shut off the heat. At this point, they say it's ready, but they claim you can leave the corn in the covered pot as long as the next day and it'll still be great.

After cooking more than 60 samples of corn, I've found that their method wasn't far off—but the very best, most foolproof way involves no boiling at all. Now wait—wait—because some of you have probably heard this line before and are wondering why I'm writing it as if it's something new. For those who don't know, the "best corn isn't boiled" line is more or less identical to the advice Cook's Illustrated has long given, but my method is different in small but important ways, and when I say no boiling, I mean it. Literally no boiling. Not before the corn is put in the pot, and not after.

In all my testing, though, I've come to the conclusion that there are a couple other worthy methods of cooking corn on the cob. One of them is, in all honesty, the way I most often cook corn at home, especially when I want a cob for myself after a trip to the farmers market: the microwave. In side-by-side tests, I've confirmed it is a great method that can produce excellent results. The other method that works quite well is steaming, which does involve boiling, but thankfully it's a much smaller quantity of water, which is a plus both in terms of time and energy use.

What Is "Perfect" Corn on the Cob?

What is "perfect" corn on the cob? I tend to like mine a little on the less done side, even enjoying a raw ear from time to time, while others want theirs fully cooked and tender. Some people prefer the ultra-long-lasting-sweetness of modern corn hybrids, and others will swear that what we've gained in sustained sweetness has been at the expense of the more robust corn flavor of older varieties.

I think we can all agree, though, that what we don't want is corn that's left to swelter until shriveled and mushy, its flavor lost to the pot and heat. Generally speaking, we want corn on the cob that is sweet, not starchy, with kernels that are plump and tender, and not in the least bit shriveled or mushy.

To a large degree, corn quality starts at the market, so before we get to cooking methods, let's go over a few shopping and handling tips I rely on to make sure I'm setting myself up for success before the cooking starts:

Shopping and Handling Tips for Corn on the Cob

Corn famously loses sweetness as soon as it's picked, its natural simple sugars converting into less sweet, more complex starches with each passing minute and hour. In reality, modern hybrids hold up much better than they used to as far as sweetness longevity goes—no longer do you have to race from field to cooking pot to lock in the sugars before they fade. But time still isn't on your side, so you want to make sure you pick fresh ears of corn at the market, then avoid waiting long before cooking.

Here's what to look for:

• Moist silks: The silks are one of the best indicators of how recently an ear has been picked. Look for corn silks that are moist and soft, not brittle and dehydrated.
• Perfectly developed size: Apply the Goldilocks rule to assessing corn maturity—you want ears that are neither too small and underdeveloped nor too large and overdeveloped. There's a habit among some corn shoppers of tearing cobs apart, stripping away the husks to study the entire ear before deciding whether to put it in their bag or not. Don't do that. It not only makes a mess and ruins the corn for subsequent shoppers, but it's also unnecessary. If you want to check the status of an ear, gently pull back the husk only at the tippy top of the ear to peek at the kernels just at the tapered end. This is sufficient for sussing out whether you've got an immature ear with underdeveloped kernels or an older one that's grown chunky and tough with time. A lot of times, you can even just feel it in your hand through the husk—does the cob feel moderately substantial without being a lumpy brick or a scrawny featherweight? If the answer is yes, you're likely holding a good ear.
• Don't worry about bugs: I'm not saying you should buy ears of corn that are riddled with worms, but caterpillars will find their way into sweet ears of corn and it's really not the end of the world. If anything, it's a sign the corn is tasty—certainly the caterpillar thinks so.

Once you've completed your shopping, as mentioned above, try not to wait too long before cooking the corn. I generally try to eat through my market haul within a day or two at the absolute most; if you do have to wait, the colder temperature of the refrigerator will help preserve sugars longer.

The Scope of Testing

The question I'm trying to ask here is: What's the best way to boil an ear of corn? That's the literal question, but what I'm really after is not a specific method, but a specific result, so my testing included not only boiling but also any other method that delivers a result akin to boiling. This means I also tested microwaving, steaming, and cooking at sub-boiling temperatures. What I didn't test were all the other ways to cook corn, so this is not a guide to grilling, roasting, air frying, deep frying, sautéing, or anything else.

I also didn't include sous vide in my testing, even though it arguably produces a like-boiled result. I kept it out for two reasons: First, because we already have Kenji's in-depth guide to sous vide corn, and second, because it's a much more impractical method that wastes a lot of plastic (you need to double bag the corn). If you want to cook your corn sous vide, by all means please do, but it requires more planning, time, and materials and therefore isn't the kind of everyday solution I'm after.

The Science of Cooking Corn

The objective of cooking corn on the cob is twofold. We want to gelatinize the starches in the kernels, swelling them up so that the corn loses the milky starchiness it has when raw. At the same time, we want to minimize the breakdown the corn's natural pectin, which contributes to its cellular structure. That breakdown of pectin is largely responsible for the shriveled kernels of overcooked corn.

The trouble is that at the high temperatures of simmering and boiling, both starch gelatinization and pectin degradation are happening at the same time. This was precisely the challenge Cook's Illustrated had identified in their article on perfect cooked corn, and they rightly concluded that cooking the corn at a sub-boiling temperature somewhere in the zone of 170 to 180°F was the sweet spot—high enough to gelatinize the starches but low enough to avoid too much damage to the pectin. This basic fact is also why Kenji set his sous vide corn recipe to 183°F—it's just below the temperatures at which pectin breaks down.

My goals today are no different, and I knew going into this that I'd be sniffing around the same temperatures and methods that Cook's Illustrated and many others have before me. I just landed in a slightly different place once I was done.

The Best Methods for "Boiling" Corn

Let's jump right in. Here are all the methods I tried and my results. (Note: As with all Serious Eats tests, I standardized all possible variables, including water volume and corn quantities.)

Basic Boiling

The question is "what's the best way to boil corn" so I obviously had to try straight-up boiling. I brought a large pot of water to a rolling boil and then dropped my shucked ears in and started a timer right away (before the water had returned to a boil). The water returned to a boil about two minutes later, and I then began pulling ears of corn out every minute starting at four minutes (the shortest recommended time I saw in boiling recipes) and all the way up to ten minutes.

Just based on visual inspection alone, I could see the signs of the high heat on the corn: While subtle on the three- and four-minute samples, all the corn had visible wrinkling of the kernels, indicating the pectin was breaking down and the corn was shrivelling.

The four-minute samples were pretty good—if you served them to me with no comment, I'd happily eat them and and not think twice about it—but all the samples from five minutes up were increasingly overcooked, with a less sweet, more pasty flavor and texture.

Verdict: Boiling corn for a very short period of about three to four minutes (timed from the moment the corn is added to the boiling water) produces decently good corn, but signs of the kernels shriveling are visible. Anything longer than five minutes is not recommended. Overall, actually boiling boiled corn is not ideal.

The Cut-and-Wait: The Cook's Illustrated Preferred Method

I've seen this method with slight variation over the years, but it is based on some variant of the idea that it's better to let the corn sit off-heat than to continuously boil it. The method goes something like this: Bring a pot of water to a boil; cut off the heat; add your corn; cover and then wait for it to cook off heat for some minimum time up to some maximum time. For Cook's Illustrated, that's a minimum of 10 minutes up to a max of 30 minutes.

Their explanation for why their method works is that the corn immediately lowers the temperature of the just-boiled water to the ideal zone of around 180°F, where it then can hang out until done. This can work, but it's not foolproof and it's not flexible. That's because the Cook's Illustrated recipe specifies a water volume (four quarts), and a number of ears (six). That's a problem, though, because not all of us always want to boil exactly six ears of corn in four quarts of water.

When I ran my tests on this method, having read the Cook's Illustrated method but missing the critical six ears part, I put four ears of corn into Dutch oven filled with about four quarts of just-boiled water, and then watched as the water failed to fall anywhere even close to 180°F. After one minute, it was up at 200°F; after three minutes, it was down to 190°F; and after five minutes at was still in the high 180s. Only at the 10-minute mark, when I removed my first sample, did the water reach 180°F.

In terms of actual results, these ears were better than boiled corn, but not perfect: The 10-minute sample was good, but from 11 minutes and higher, the corn showed minor signs of shriveling. Most likely, I would have had better results had I used six ears. But this basic fact convinced me to move on. I wanted a method that worked consistently no matter the amount of corn you're going to cook, and largely irrespective of the volume of water.

Verdict: If you follow the limited parameters exactly, this can work, but why commit to a method that only works if you boil six ears of corn in four quarts of water? We can do better.

Cold Start (The Winner)

If temperatures above boiling are a problem for "boiled" corn, a logical question follows: Why boil the water at all?

To find out, I dropped all my ears into a pot of cold water, then put it over high heat and brought it all up to 180°F together, which was easy to check with an instant-read thermometer. Then I covered the pot, turned off the heat, and let it stand.

This method accomplished a couple things. It avoided the need to overshoot the ideal temperature of the water by bringing it to a boil, saving time and energy, and eliminated the imprecise method of using the cold or room-temp corn to drop a too-hot pot back down to the ideal zone. In my cold-start method, everything in the pot went up to 180°F together, and then it all stayed in that zone until I started pulling samples at 10 minutes and continuing every minute up to 25.

This corn was superior. All the samples were perfectly plump and tender, with a sweet, juicy pop. None of them showed signs of puckering except for the 25 minute sample, which had very, very minor signs of it (at the 25-minute mark, the water was down to 155°F, at which point the corn was no longer cooking much at all and instead just being kept warm in an aqueous environment.

Verdict: This method was the best, producing corn that was perfectly cooked but still bursting with off-the-stalk vitality. Even better, since it's based on more precise temperature control, it works across a wide batch sizes and pot sizes: As long as you get your corn and water up to 180°F and then let it sit in that water for at least 10 minutes, it'll be perfect. This method offers excellent flexibility on time, since there's a much larger window for great results; I maybe wouldn't let my corn hang out in the water for more than about 25 or 30 minutes, though it'd probably still be pretty good even after that.

Steaming (Another Winner)

Another good question is: Why not skip the whole submerging-corn-in-water-thing and steam it instead? To find out, I brought a pot to full steam, added the corn on a steaming rack, and then let it steam, pulling my first sample at three minutes and then every minute after that up to seven minutes.

I was surprised by how well this corn turned out. Even though steam is the temperature of boiling water (212°F at sea level) and is at an elevated energy level, it's less dense than water, which leads to very even but more gentle cooking. In effect, this means that even though steam is hotter than the ideal temperature for boiling corn, it produces successful results, especially on the shorter end of the time spectrum at three to four minutes (longer-cooked samples were also good but starting to lose some vibrancy).

Verdict: This is a good and efficient option, and the small amount of water required speeds the cooking time up compared to traditional boiling—it's much quicker for an inch of water to reach the boiling point than to heat a whole pot. I still like the cold start more for its large margin of error on the cooking time, and for its overall precision within the ideal cooking temp zone, but steaming is a valid alternative.

Microwaving (Yet One More Winner)

Last thought—why use water at all aside from the natural water of the corn? That's where the microwave comes in. Simply pop the corn, still in the husk, in a microwave and run it on high power for a few minutes. Exactly how long depends on how many ears of corn you're cooking and the power of your microwave, but I find that two to three minutes is good for a single ear, while five to six minutes can be good for about four ears at once.

Some people like to add a step in which you cut off the bottom of the corn just above the stem so that you can more easily slip the ear out of the husk once it's cooked, supposedly free of almost all its silks. I haven't had great luck with this little trick, but maybe that's just me. Perhaps with a little more practice I can nail the dismount.

You're also likely to see this method recommended two ways: One requires microwaving the corn in its husk, the other has you shuck the corn first, then wrap the ears in damp paper towels for the microwaving part. Let me save you the time right now: The shuck-first method is to be avoided. Not only does it needlessly waste paper towels, but it does away with the perfect natural steam jacket for each ear—its own husk—in favor of a less effective artificial one.

For the record, this is the method I use at home the most: It's easy, it's fast, and it works even for individual ears of corn, which I scarf down while standing over my kitchen sink in the middle of the hottest days of summer.

Verdict: This is another great, low-effort, high-efficiency method for quickly cooking smaller amounts of corn. It's essential to microwave the corn in its husk, which is the better, more natural, less wasteful way to trap steam around each ear. This method will possibly require some tinkering at home with your own microwave and corn, but once you figure out your preferred cooking times, you'll be very happy with the results.

Salt and Flavorings

Before wrapping up my testing, I had one small remaining question, which had to do with seasoning the cooking water for the methods that involve submerging the corn. Really, the big question was whether it made sense to add salt or not, but I also had a (somewhat strange) thought that maybe the husks could add a deeper flavor if tossed into the pot with their ears (I think maybe I was riffing on the fact that corn grilled in its husk is so good and flavorful and wanted to see if that translated to other cooking methods, but I admit it was a stretch). While the water could also be flavored with countless other things like herbs, I didn't go down that testing road; it felt too finicky and troublesome for the humble boiled ear of corn.

To look once more at that Cook's Illustrated corn article—I'm not trying to pick on them, they just have one of the most in-depth and science-based discussions of corn boiling out there, so it's hard not to reference them here—they claim that salting the corn cooking water makes no difference. In their tests, they found that the salt was unable to penetrate the kernels unless they ears were allowed to sit in the water for an excessive amount of time. The explanation they gave was that the salt can only really work its way into the kernels by being absorbed through the cob first, which is a slow process. Their conclusion: Don't bother salting the water, just season the corn afterwards when you serve it.

To check on this, I made a 2% salt solution and cooked my corn in that following the cold-start method I'd already identified as my favorite. After cooking, I tasted a piece of the corn and found it nicely seasoned. Perhaps, I thought, the salt is just on the surface and if I rinse the cobs I won't taste it any more—that'd align with the Cook's Illustrated finding. So I ran my corn under running fresh water for about ten seconds, then tasted it again. And it was still very clearly seasoned with salt!

What's this about? I suspect Cook's Illustrated is more or less right about salt not really getting into the kernels quickly or easily, but even if they are right, my testing indicates that even as a surface treatment, salt is able to cling to the corn and burrow down into the the tight spaces between the kernels such that even washing won't fully remove it. Does that mean salting the water is invalid just because it's a surface treatment? Not in my book! It seems like a good way to get even seasoning all over the corn without overly salted spots or bits of undissolved salt sprinkled on it.

At the same time, though, I don't think salting the water is essential. Adding salt to the cooking water is more wasteful of salt, because the only way to get it salty enough requires adding enough to season not just the corn but all of the water—just like when you cook pasta. Most of that salt ends up going down the drain with the water when you dump the pot out.

I should also note that I saw no ill effects of salting the cooking water. I say this because we already know that brining corn is a really bad idea. But it seems that the cooking time for the ears of corn is short enough not to cause the corn to dry out.

As for cooking the corn with the husks in the water, it was a dumb idea, let's forget I even tried it.

Verdict: Salt may just be a surface treatment that doesn't penetrate into the kernels of corn quickly enough, but it's still a surface treatment that works. Salt your cooking water if you want to (make sure the water tastes nicely seasoned, just like pasta), or don't and save the salt for serving time. Works either way.