Poaching fish—gently cooking it in a liquid over low heat—is a classic French technique. Traditionally, the poaching liquid is a light broth, known as a court bouillon, and the finished fish comes out delicious, light, and flaky.
That classic technique is the foundation for a different way of cooking fish—poaching in olive oil. In simple terms, this method involves submerging a piece of fish in a bath of warm olive oil and then cooking it in the oven at a low temperature to perfect doneness. The fish emerges with a tender, silky texture and a pure seafood flavour that is hard to achieve with any other cooking method.
Three keys to olive oil poaching
The fish: Choosing the best fish should be your primary goal. The fish must be rich in flavour and firm in texture. A few examples are: salmon, halibut, tuna, and shrimp. Make sure your fish steaks or fillets are at least 3/4 inch thick.
The oil: Olive oil poaching calls for the usage of extra-virgin oil. This is because extra-virgin olive oil’s rich flavour will penetrate the fish. Use a modest brand and not your precious drizzling oil. You will need a lot.
The pan: Choose a straight-sided sauté pan or saucepan that will hold the fish in a single layer. Crowding the pan is not an issue as long as the pieces do not overlap.
Steps involved in olive oil poaching
Season: Remove the fish from the refrigerator, season, and let it sit at room temperature for about an hour.
Heat: The olive oil should be heated over low heat, just until it reaches 40 degrees Celsius. To be sure, use an instant-read thermometer to monitor the temperature.
Poach: Finally, transfer the pan with the fish to the oven and poach for 25 minutes. Be sure to keep track of time.
About time: One of the remarkable things about this technique is that the timing is virtually foolproof. Twenty-five minutes is the magic number for perfectly cooked seafood. This timing depends on letting the fish sit at room temperature for about an hour before poaching; straight-from-the-fridge fish would dramatically lower the temperature of the oil and throw off the cooking time.
The best doneness indicator is the appearance of white droplets of albumin (protein) on the outside of the fish. You can also use a paring knife to make a small cut in a piece of the fish to visually check for doneness.
Try it out: Depending on the recipe, you will be using about four to six cups of oil to poach the fish. The added benefit is that you can reuse the oil to poach more seafood. Let the oil cool to room temperature and then strain through a fine sieve lined with a coffee filter. Stop straining before you reach the bottom, as any liquid released from the seafood will have settled there. Discard this last bit, cover the remaining and store in the refrigerator for up to three weeks.
Olive oil poached salmon with Indian spices
1 large garlic clove
1 tsp. garam masala
1 tsp. cumin seed, toasted and ground
1 tsp. coriander seed, toasted and ground
1/4 tsp. cayenne
4 to 6 cups extra-virgin olive oil
Four 3/4- to 1-inch-thick skinless center-cut salmon fillets (170 to 198 grams each)
4 lemon or lime wedges
Peel and smash the garlic clove and add a pinch of salt. Mix into a paste either with a mortar and pestle or mince and then mash with the side of a chef’s knife.
Combine the garlic, garam masala, cumin, coriander, cayenne, and one tsp. salt in a small bowl.
Add about one to two tsp. oil, just enough to turn the spice mixture into a smooth paste. Then rub the spice paste all over the salmon and let it sit at room temperature for about an hour.
Position a rack in the center of the oven and heat the oven to 107 degrees Celsius.
Measure the thickness of the fillets and pour the same depth of oil into a 10-inch straight-sided sauté pan.
Heat over low heat until the oil reaches 48 degrees Celsius (2 to 3 minutes).
Put the salmon fillets in the oil in a single layer and immediately transfer the pan to the oven.
Poach for 25 minutes, until a few small whitish droplets rise to the surface of the fillet.
Once done, transfer the salmon to a wire rack to drain for a few minutes.
Serve warm with lemon or lime wedges.