How to Poach Fish in Olive Oil For a Quick and Delicious Dinner

Poaching fish in olive oil is a striking way to elevate your dinner menu. The technique yields buttery, succulent fish that tastes as silky as it looks. What's more, oil-poached fish makes for a quick, low-maintenance meal that's elegant and healthy to boot. If you've poached food in water or cooked sous vide, you already have some of the skills needed for oil poaching. It's certainly worth adding to your kitchen repertoire, especially if you're looking for new and exciting ways to cook fish.

What Is Oil Poaching?

The technique is a type of poaching, which involves submerging food in a hot liquid—in this case, olive oil. The oil essentially envelopes the food in fat, helping seal in its flavor, says Greg Lofts, our deputy food director. The food is also cooked low and slow, unlike the high temps and quick cooking times traditionally used in deep frying. For example, in our recipe for oil-poached halibut, the fish cooks for 8 to 12 minutes at less than 150 degrees. The result is a tender, juicy fillet that will make your taste buds sing. All that being said, if you're an olive oil enthusiast, you'll want to skip your premium drizzling and dipping oils when trying this technique. The fish will need to be fully submerged in olive oil, so you'll need a decent amount—about one cup, depending on your recipe. Consider using a more budget-friendly option for this purpose.

When it comes to types of fish that can be poached in oil, the sky (or sea) is the limit. In general, the varieties best suited for oil poaching are meatier and oilier, such as tuna, swordfish, mahi mahi, mackerel, bluefish, salmon, halibut, and striped bass, says Bianca Piccillo, co-founder of sustainable seafood store Mermaid's Garden. But don't limit yourself to fish; according to Greg, seafood like shrimp and octopus also poach beautifully in oil.

How to Do It

The first step is to bring your fish to room temperature. This will ensure that it cooks evenly in the oil, says Greg. Next, generously season the fish with salt and spices. It's best to do this beforehand, notes Greg, as the oil will pull the seasoning into fish. (It's a similar concept to canned tuna in oil, he adds.) Coat the bottom of a pot with olive oil, add the fish, then pour enough oil to fully cover the fillets. Attach a deep-fry thermometer to the pan, heat the oil to the temperature listed in the recipe, then reduce the heat to maintain the required temperature. Aim for a low, gentle simmer—make sure the oil doesn't come to a boil. The fish is ready once it becomes opaque, about 10 minutes, depending on its thickness. Finally, remove the fillets with a slotted spoon or spatula, pausing to let the excess oil drip off before transferring it to a plate.

How to Reuse Oil After Poaching

To get the most out of your succulent meal, save the olive oil. After it cools down, "strain the oil through a fine mesh sieve or cheesecloth," says Greg. This will filter out any bits of fish that might have broken off during cooking. Pour the oil into a clean, empty dark glass bottle, label it with the date, and store it in area away from heat or light. Avoid using this oil in recipes like dressings, marinades, drizzles, or dips because Greg explains, olive oil loses its grassy notes when heated, and these are the characteristics you'd typically want in these raw preparations. Instead, use the oil for cooking other fish and seafood using high-heat applications, like pan-frying, roasting, or sautéing.