Why Use Cast Iron To Sear Rockfish
Chesapeake chef Spike Gjerde shares the key to pan-cooking rockfish..
When Spike Gjerde opened his flagship Woodberry Kitchen in an old mill in northern Baltimore, he knew two things for sure about the future of his farm-to-table restaurant.
Dedicated to hyper-regional sourcing and the culinary heritage of the Chesapeake Bay from day one, “I knew that this trinity of local seafood—oysters, crab, and rockfish—was going to be important for us,” says Gjerde, as famed writer and fellow Baltimore native H.L. Mencken once dubbed the working estuary an “immense protein factory.”
“We also made the decision from early on to do a lot of cooking out of our woodfired oven. The intersection of those two commitments was inevitable. And it turns out one of the most felicitous discoveries I’ve ever made is how well wood-fired ovens go together with cast iron.”
Today, 12 years and a James Beard Award win later for Best Chef: Mid-Atlantic, all three keystone species of the Chesapeake still appear as star staples on Gjerde’s ever-changing menu, much of which comes out of an 800-degree brick hearth situated in the heart of their industrial dining room by way of a cast-iron pan.
Most notably, perhaps, is one of the restaurant’s summer and fall signature preparations—pan-roasted rockfish—also known outside of the state as striped bass. In true fashion, it’s a dish, often done in our Heather, that follows Spike’s local food ethos to the core.
“This rockfish is from the Chesapeake Bay, seasoned with salt from J.Q. Dickinson in nearby West Virginia and fish peppers that are grown here in Maryland and used as part of our Snake Oil hot sauce production, cooked in sunflower oil from Pennsylvania—and that’s it,” says Gjerde. “I’m interested in creating flavors that express the nature of a place, and it’s difficult to capture a terroir when you have access to global ingredients. If this had a squeeze of lemon and fleur de sel and black pepper, it would be delicious, there’s no question. But would it represent this place?”
For Woodberry, that always begins with fresh rockfish. “Super fresh fish that’s been well handled and pretty much on ice since it was caught,” says Gjerde, who sources his seafood from local watermen along the Chesapeake and Atlantic Ocean.
But once the fire is stoked, the tables are set, and those first tickets start flooding into the kitchen, the key to cooking it comes into play—a simple moment of preparation that can make or break the meal.
To many a chef and home cook’s dismay, fish flesh retains a lot of moisture, and “moisture is the enemy,” says Gjerde. Without thoroughly dry filets, time is wasted evaporating excess liquid off the pan’s surface, and in those moments, the fish is being steamed, not seared. The golden color and crispy texture we crave on the outside is lost before it ever begins, as the moisture has reduced the heat needed to produce the Maillard reaction of browning protein, and oftentimes, so is the tender meat inside, as the filets effectively turn to rubber or mush.
“If the fish isn’t dry, if the pan’s not nice and hot, you won’t get that crispy skin or any of that good browning before the fish is already fully cooked,” says Gjerde. “Then you’re trying to add color and crispiness after the fact, and all you’re really going to do is overcook.”
Gjerde’s secret weapon? Like most of us, he still dries the filets with paper towels before they’re seasoned, but as the pan pre-heats in the wood-fired oven, he also uses the back of a chef’s knife to literally squeegee the fish’s skin.
Like a car’s windshield wiper, the blade’s flat surface physically presses out any residual wetness, giving way to a near bone-dry piece of fish and that golden crispy goodness we were looking for in the first place. Simply eyeing at the knife’s edge will tell you if you’ve swiped enough. (Is it still slick? Keep going.) Just be careful not to puncture or cut the fish’s skin.
From there, the process is largely foolproof, says Gjerde, and equally so for home cooks, whose conventional ovens top out at 500 degrees, still an ideal temperature for roasting fish. After the cast iron is pre-heated—which takes only about five minutes in Spike’s kitchen, or 10 to 15 minutes in ours—he pours an eighth of an inch of oil into the bottom before carefully adding the filets and returning the pan to the oven.
“For us, from there, the whole process takes only about eight minutes—four to five minutes, skin-side down, then turned, very carefully, and finished, skin-side up,” says Gjerde, who serves the rockfish with a seasonal succotash made using essentially the same process in the same pan with the same heat—another simple ode to Maryland summer, and Chesapeake terroir. “That’s it, and it’s just going to be beautiful.”