This recipe for fish fumet is courtesy of chef Eric Ripert and used to make his Le Bernardin Fish Soup.From "Le Bernardin Cookbook: Four-Star Simplicity" by Maguy Le Coze and Eric Ripert. Copyright 1998 by Maguy Le Coze and Eric Ripert. Used by permission of Doubleday, a division of Random House.
If you are preparing the fish yourself, remove the gills and the eyes. Cut the heads and bones across into 4-inch pieces. In a shallow pan filled with cold water, add the heads and bones. Cover, and let stand for 1 hour, changing the water twice.
In a large stockpot set over medium heat, add corn oil, onions, fennel, leeks, peppercorns, salt, parsley, and bay leaves. Reduce the heat to medium low, and cook until the vegetables are soft but not browned, about 4 minutes.
Transfer heads and bones from water to the stockpot; discard water. Stir periodically until bones and flesh around bones turn from translucent to white, about 12 minutes.
Add the wine and 6 cups of water; bring to a boil over high heat. Boil fumet 10 minutes, skimming off the foam as it rises to the top. Remove from heat; let rest for 10 minutes.
Strain the fumet through a fine-mesh sieve or chinois, pressing firmly on the solids to extract as much of the flavorful liquid as possible. If you have more than 6 cups of fumet, place the liquid in a clean saucepan over high heat, and boil until it reduces to 6 cups. Store, tightly covered, in the refrigerator up to 3 days, or in the freezer up to 2 months.