Tips for Working with Salmon Fillets

That gray portion of tissue is a fatty deposit rich in omega-3 fatty acids and low in the natural pink pigments found in the rest of the fish. To get a handle on how the gray area affects flavor, we oven-roasted several fillets of salmon, then removed the gray portion from half of them and left it intact on the others. Only a few discerning tasters noted that the samples with the gray substance had an ever-so-slightly fishier flavor; most couldn’t tell the difference. It’s easy enough to remove the gray stuff by peeling off the skin of the cooked salmon and then scraping it away with the back of a knife, but the flavor difference is so minor that we don’t think it’s worth the hassle.

We cooked three batches of 1-inch-thick fillets on a wire rack set in a baking sheet at various oven temperatures until they were 125 degrees at the center. We then watched how that number rose as the fish rested for 5 minutes. The salmon cooked at 250 degrees carried over an average of 7 degrees, just above the ideal 130 degrees for serving. The salmon cooked at 325 degrees rose 9 degrees at its center after 5 minutes, while the fish cooked at 350 degrees rose 15 degrees. And at 450 degrees? The salmon’s temperature rose a whopping average of 27 degrees after 5 minutes. These tests underscore why a low oven temperature can work best for fish, since the hotter the oven the more dramatic the carryover cooking. A low oven temperature will help ensure that the flesh is evenly cooked from edge to center and stays near the ideal doneness temperature until the fish is served.

Fish is notoriously susceptible to overcooking, so reheating previously cooked fillets is something that makes nearly all cooks balk. We recommend serving cooked thin fillets in cold applications like salads because reheating them causes them to overcook. To reheat thick salmon fillets, use this gentle approach: Place the fillets on a wire rack set in a rimmed baking sheet, cover them with foil (to prevent the exteriors of the fish from drying out), and heat them in a 275-degree oven until they register 125 to 130 degrees, about 15 minutes for 1-inch-thick fillets (timing varies according to fillet size). Just one note: Thanks to the oxidation of its abundant fatty acids into strong-smelling aldehydes, reheating fillets brings out a bit more of the fish’s pungent aroma.

Because fish is so perishable, it’s best to buy it the day it will be cooked. But if that’s not possible, here is the best way to store it. As soon as you get home with your fish, unwrap it, pat it dry, put it in a zipper-lock bag, press out the air, and seal the bag. Then set the fish on a bed of ice in a bowl or other deep container (that can contain the water once the ice melts), and place the bowl in the back of the fridge, where it is coldest. If the ice melts before you use the fish, replenish it. The fish should keep for one full day.

Unless the salmon you’ve bought is literally the catch of the day, chances are it will smell and taste at least a little fishy, thanks to a compound found in nearly all seafood called trimethylamine oxide, or TMAO. This compound is odorless when fish and shellfish are alive, but once they’re killed, TMAO slowly transforms into TMA (trimethylamine), which has a fishy odor. But that doesn’t mean that the seafood has gone bad or is unusable. We’ve found an easy way to eliminate the smell: Soak the fish or the shellfish meat in milk for 20 minutes and then drain and pat dry. The casein in milk binds to the TMA, and when drained away, it takes the culprit that causes fishy odor with it. The result is seafood that’s sweet smelling and clean-flavored.