From America's Test Kitchen
Cooking delicate salmon can be tricky. Even using a nonstick skillet, it’s still easy to break the occasional fillet. Introduce that same fillet to a grill, and you’ve got a real challenge. We wanted grilled salmon with a tender interior and crisp skin, and with each fillet perfectly intact.
Part of the solution lay in a procedure we developed to clean the grill thoroughly: Place an overturned disposable aluminum pan over the grate as the grill warms up, trapping hot air and superheating the grate. Just like in a self-cleaning oven, the high heat causes grease and debris to disintegrate. By replacing the disposable pan with foil pressed against the grate, we bumped the temperature up higher, making the technique even more effective. We chose thicker salmon fillets, which could stand the heat of the grill for a little while longer before the first turn. To prevent the fish from sticking, we dried the fish’s exterior by wrapping it in kitchen towels and “seasoned” our cooking grate by brushing it over and over with multiple layers of oil until it developed a dark, shiny coating. After laying the fillets on the grate, we easily flipped each fillet without even the tiniest bit of sticking.
This recipe works best with salmon fillets but can also be used with any thick, firm-fleshed white fish, including red snapper, grouper, halibut, and sea bass (cook white fish to 140 degrees, up to 2 minutes longer per side). If you are using skinless fillets, treat the skinned side of each as if it were the skin side. If your fillets are thicker than 1 inch, increase the cooking time on the second side in step 3 until the center of the fillet registers 125 degrees (or 140 degrees for white fish).