Fish skin. Normally, you nudge that dark, slimy heap to the side of your plate. You can see what it tastes like: low tide, trash. Why would anyone serve fish with its skin on?
Because when it’s done right, the skin of many fish is exquisite, never more so than when it’s crisped to a delicate wafer-thin crunch accompanying the sweet, soft flesh. Crisp fish skin should taste clean and fresh, with the concentrated flavor of the fish itself. Its colors and design are vivid on the plate. The fork clicks on its surface. It cracks brittlely beneath a knife.
Crisping fish skin is easy, but it brings the risk of overcooking the delicate meat. Fortunately, there are tricks to avoid that. The first and most critical step is to remove as much water from the skin as possible before you cook it. Skin will not crisp as long as there’s moisture in it; until then, it will only steam. And if you try to get rid of that water by heat alone, the fish will overcook before the skin can crisp.
So remove some of that water mechanically, by drawing a knife blade firmly back and forth over the fish, the way a wiper blade moves across a windshield. The pressure compresses the skin and squeezes the water to the surface, and the knife blade carries it away. Repeat this until no more water rises to the surface.
If you need to store the fish, put it in a container skin side up so moisture doesn’t sink back into the skin from the meat. Cover the container snugly, but leave a little room for air between the skin and the lid.
Finally, the pan you cook the filet in should be very hot but the oil should not be smoking. Lay the filet in it skin side down, pressing the fish with a spatula to keep all the skin in contact with the pan, and reduce the heat to medium. If you’re cooking several pieces of fish, you may want to set a clean pan on top of the fish so you can press all of them at once.
How long you cook the fish will depend on how thick the skin is and how much water remains. When the skin is crisp, turn the fish over to complete the cooking.
This technique works best with salmon, black bass, striped bass, sea bass, arctic char, turbot, whitefish and cod. The fish should be meaty and the skin should be relatively thin. When you’re cooking big pieces, scoring the skin can enhance the appearance, facilitate seasoning on the skin side and reduce buckling as well.
It’s impossible to crisp the skin of some fish. Mullet and mackerel, for instance, are too oily to crisp (though they are still fine to cook and serve with the skin on).
We love crisp foods; they have an all but universal appeal. Though we usually think of fish as being soft, delicate and flaky, it does come with a perfect crisp component already attached, if you know how to achieve it.