Ah, this debate rages on. Those who have seriously considered it often disagree. Who’s right?
If you’re talking about meat to be pan-broiled or pan-fried, I was taught to salt midway through the cooking process. First dry the meat, which is preferably at room temperature, with a paper towel so it will sear properly. Preheat the pan and film it lightly with oil – the oil should be shimmering, almost but not quite at the point of smoking. Lay the meat down in the pan away from you, and leave it undisturbed about five minutes, until it has formed a nice brown surface. When that side has seared properly, it will release easily from the pan; now is the time to turn it over and salt and pepper the seared side.
Salt draws moisture, so after a few minutes of cooking, you’ll see beads of collagen begin to form on the surface of the meat. To finish cooking it through, you can now either leave the meat in the pan and turn the heat down a bit, or put the pan in a 350° oven. When it tests about 5-10 degrees less than your desired final internal temperature, remove from the heat. Allow to stand for a few minutes to allow the meat juices to redistribute themselves throughout the meat before serving. Otherwise, they’ll rush out as soon as the steak is cut into, and it will be dry.
Shirley Corriher, in CookWise (a book which explains how and why things happen in cooking) suggests a different technique for salting a pan-seared steak. A heavy pan such as cast iron, which won’t warp when heated to a high temperature, is essential. The pan is preheated so that the surface is very hot, and then sprinkled with a thin layer of salt. The steaks are placed on the salt, seared for three minutes, and turned. The steak continues to cook until “you see beads of moisture (juices) coming through the steak crust… Serve immediately.” She explains that, “Salt draws juice from the meat surface, adding proteins and sugars to the surface and reducing its moisture content for better browning.”
I’ve never tried this, but it makes sense. There is one drawback. If you want a plain grilled steak, fine. If you’d like to make a pan sauce with the fond, the browned bits left after searing, they’d be too salty with this method; your sauce would be ruined.
Here’s the reasoning behind salting meat before cooking. For it to work effectively, you’ll need to salt the meat at least an hour before cooking it. This will draw the juices to the surface of the meat; the juices will then dissolve the salt, creating a brine. Within the hour that brine will be reabsorbed into the meat. This will both flavor the meat and tenderize it, a nice dual effect. Try it next time you’re in the kitchen with a steak an hour before you want to cook it.
A caveat — all of the above applies to whole pieces of meat. Burgers made of nothing more than ground meat should be salted immediately before cooking. Because the surface of the meat is so much more open than a solid piece of meat, salting in advance will draw too much moisture, and you’ll end up with a tough burger. Don’t salt ground meat before forming it into a patty for the same reason. The same is not true of mixtures like meat loaves or meatballs which have bread and liquid added along with the seasonings. Burgers can also have these additions, but I don’t care for the flavor. The benefit is that you can cook the burger to well-done, thus satisfying the food police (a valid enough concern if you’re serving someone with an immature or compromised immune system.) But I’d rather wait until I have access to beef from a trusted source and enjoy it cooked medium, with all its essential meatiness intact.
What about roasts? Salting an hour before cooking allows the formation and re-absorption of brine, as described above. The thickness of a roast, however, means that salting 24 hours or more beforehand will give better results. If you have the time and the forethought, go for it. If you want that roast tonight, though, and you just thought of it, go ahead and salt right before putting it in the oven. It will be fine.
You’ll notice there’s no mention above of salting after cooking. That’s because seasoning should be an intrinsic part of the cooking process. It’s possible to adjust seasoning when a dish is finished – which is why so many recipes mention it at the end – but if a dish hasn’t been salted at some point during the cooking, it’s difficult to completely make up for the lack. The salt won’t have become an integral part of the dish.