The key to seasoning a steak before grilling it is to use a generous amount of Kosher salt. More than you think you need. One of the most common mistakes home cooks make is undersalting their food—especially meat. Only use coarse-grained Kosher salt, NOT ordinary table salt.
How to Season Generously
Steak is often pretty thick. An ideal size that follows guidelines for selecting the best steak is about an inch and a half thick. The salt is only seasoning the surface, which means a significant portion of the meat has no salt on it at all. That's why it's imperative to salt generously. If you were only eating the surface of the steak, it might be too salty. But you aren't. You're eating the whole steak. The seasoning on the surface has to be enough to properly season each bite.
When to Salt the Steak
When to apply the salt is a common seasoning question. Some chefs like to salt a steak well in advance of cooking, even up to 24 hours in advance. Others say salting it right before cooking is best. The main drawback of seasoning in advance is that salt applied to the outside of something tends to pull water from the center of it onto the surface. If the thing in question happens to be a steak, it will necessarily be less juicy. In fact, any steak you hold in the fridge, salt or no salt, is going to lose juices overnight.
Another drawback is that it extends your prep time. Seasoning your steaks 24 hours in advance of cooking, means you're in the kitchen 24 hours before dinner working with the steaks. You also need to make room in your fridge for these steaks for an additional 24 hours.
Seasoning Your Steaks in Advance
If you're ok with starting early and want to give this method a try, here's how: Pat the meat dry with paper towels and sprinkle both sides of the steaks generously with Kosher salt. Be sure to get the salt on the edges of the steaks as well. That's 1½ inches of surface you definitely want to cover. Press the salt crystals into the meat with your hands.
Transfer the steaks to cooling racks with a sheet pan or cookie sheet underneath, cover the whole tray with plastic wrap and stick them in the fridge, for up to 24 hours. Take them out about 30 minutes before cooking, pat them dry again with paper towels (because the salt will pull out some juices), season with freshly ground black pepper (press the pepper into the meat as you did with the salt), and then grill as you normally would. The reason to pat them is that a dry steak will form a browner crust when it's cooked.
Seasoning Your Steaks Right Before Grilling
If you're salting right before cooking, let the steaks sit at room temperature for 30 minutes, sprinkle both sides (and the edges) generously with Kosher salt and freshly ground black pepper. Press the salt crystals and pepper granules into the meat. You can brush the steaks with a little bit of clarified butter or a refined high-heat oil or a mixture of oil right before we grilling.
The debate over when to salt is just that—a debate. The best chefs in the world don't agree on which method is best. Both will work fine. One is easier (and maybe even juicier). Do both and decide which you prefer.
Freshly Ground Black Pepper
There's another debate about seasoning steaks, which relates to black pepper. One school of thought suggests that applying the pepper before cooking can cause the pepper to burn while you cook it, imparting a bitter flavor. Followers of this school suggest grinding pepper onto the steaks after searing them or right before serving. The other school simply seasons their steaks with freshly ground black pepper before cooking and doesn't give it a second thought.
Who's right? It's not that the notion of burning pepper is complete nonsense; in theory, yes, black pepper could burn. The problem with peppering midway through cooking is that the pepper granules might not stick to the meat. You could pass a pepper grinder at the table, but if you're cooking outside and eating in an informal style, this may not be feasible. So unless you've detected a burnt pepper flavor on your steaks in the past, by all means, season your steaks with freshly ground black pepper before cooking them.