On behalf of small corn growers everywhere, I'd like to offer a short primer on buying fresh corn. Rule #1: Don't – as in DO NOT – grab the husk at the tip and strip it back to the stem, unless you are absolutely positively 100% certainly planning to buy that ear of corn. Got that? Would you tear open a package of cookies at the grocery store and then leave it behind because one of them didn't look quite right? I didn't think so. (If you happened to answer ‘Yes’, get lost.)
Here's the thing: when you strip the husk back, and then leave the ear behind, you've started that ear on a quick path of degradation and rendered it effectively unsalable. Peel the husk away, the corn starts to dry out. Plus, it's just darned unappealing (when was the last time you bought an ear of corn that someone else had stripped naked?).
And what is it you're looking for, exactly? Did you just say ‘worms’?? Guess what? Worms happen. Not that often, really, as even organic growers have an arsenal of tricks for controlling them. And when they do happen, it's generally toward the end of the season, and the worms are limited to the tips of the ears (except in extreme infestation, in which case only an idiot farmer would bring that corn to market).
All you really need to know for choosing a good ear of corn is evident on the outside, or if you just can't help yourself, within an inch of the tip of the ear.
A good, fresh ear of corn should be heavy for its size, and the silk should be light to medium brown (it will be a bit dry and shriveled; that's normal). Its husk should be a fresh green, moist, and pliable, without spots or mold. If the husk is browning and/or dry, the corn has probably been sitting too long. Also have a look at the cut end of the stem – dry or browning there, too, indicates old corn.
As soon as an ear of corn has been removed from the stalk, the sugars in the kernels start to convert to starch and the corn gets tough, sticky and bland (and heat will accelerate the process). I prefer to cook it the day it was picked, and choose not to eat any that was picked much more than a day ago – its prized sweetness will have been lost. Real connoisseurs insist that you should cook your corn straight from the stalk – start your pot of water boiling and then go pick the corn. Most of us don't have that luxury.
If you MUST have a look inside, the most you should do is pull a small strip of husk back to expose about an inch of the ear. The kernels should be plump, shiny, and tightly spaced. Don't fret if the kernels toward the tip are underdeveloped – this is normal for younger corn. Ignore anyone who suggests you pop a few kernels with your fingernail. They are evil and are surely destined for hell for suggesting such a thing.
The bottom line is, a decent farmer knows when it's time to pick the corn for maximum flavor, and knows how to handle it and how long to store it. If you're routinely getting lousy or wormy corn, it's time to find another source.
I won't go into the gazillion ways you can cook a simple ear of corn (and everybody seems to have their own meticulous parameters, anyway). You probably already have a method all your own, and if you don't, just ask your grandmother. Or the farmer you bought the corn from.
Last summer was a phenomenal season for corn, and we ate so much I actually started to tire of it. So one night, I decided to make creamed corn. I googled around and looked in a couple of cookbooks, and was disgusted to find that every single recipe included added starch – either flour or cornstarch – as a thickener. That just didn't seem right, adding starch to something that has so much natural starch of its own. And extra starch would just goo up the flavor. I went for a simpler, cleaner approach.
After scraping the (uncooked) kernels from the cobs, I sautéed them (along with the accumulated ‘milk’) in a little butter, then added some water and salt and pepper and cooked it, covered, on low heat for about 15 minutes. As it started to dry out, I added some heavy cream, and cooked until that had reduced and was nice and creamy. This isn't the soupy cream-style corn you'll get from a can, but something a little chunkier with pure, sweet corn (and butter!) flavor. I made this again last week, but added some of the cultured cream I was about to churn into butter (sort of like sour cream or exactly like crème fraîche). Even better.
There are a lot of ways to get corn off the cob, some more elegant than others. My weapon of choice is the Corn Zipper, made by Kuhn Rikon (gotta love that smiley-face). It's got two little teeth on the underside that handily slice the kernels away. For making creamed corn, you want to break the kernels and release the milk inside, so I angle the teeth so as to rip through the tips of the kernels. Takes a little practice, but not much.