Basically the procedure for crustacean stocks is the same procedure used for chicken or meat stocks, with a shorter time, 1 hour, under pressure. If you have shrimp or lobster carcasses from previous seafood dinners saved up in your freezer you can use those or buy a couple of pounds of head-on shrimp from the Asian markets (usually around $7.00 a pound). Due to the fat in the shrimp heads, they make a very flavorful, naturally sweet stock.
3 pounds crustacean shells (shrimp and lobster) crushed up
2 pounds whole shrimp with heads on, coarsely chopped, shells and all
2 tbl neutral oil or clarified butter
1 cup white wine or dry white vermouth (optional)
1-2 tbl tomato paste (optional)
3 green onions, chopped
1 cup mushrooms, sliced
1 large carrot, peeled and cut in chunks
3 stems thyme or a fennel bulb, chopped
2 stems parley
Sauté the whole shrimp or shells in the bottom of the pressure cooker in oil or clarified butter. Add the tomato paste or the optional wine, the rest of the vegetables, and water to cover. Make sure you do not go over the maximum fill line of your pressure cooker. Lock the top into place, use high heat to get to full pressure, then turn down the heat and let simmer on high pressure for 1 hour. Remove from the heat. Let the pressure drop naturally, 7 to 10 minutes. Strain, chill and lift off the fat. Use within three days or store in the freezer.