8 Mistakes Everyone Makes When Poaching Fish

Poaching is an underrated cooking technique. It's simple and doesn't require a huge time commitment, but it has a reputation for producing fish that's bland with an off texture. When done correctly, though, poached fish is tender, moist, and wonderfully flaky, with a subtle taste influenced by the poaching liquid used to prepare it.

I first learned to poach in culinary school, where I quickly discovered how versatile poached fish could be. Poaching is a foundational technique every cook should know and it was often a featured technique in the cooking classes I taught. During my career as a personal chef, I mastered the method by preparing it regularly for clients. A poached salmon filet was always one of my favorite items to add to brunch or lunch event menus. It's simultaneously hearty and light, and it's a breeze to prepare ahead of time. You can serve it chilled or warm, and you can also customize it simply by changing the poaching liquid, type of fish, or the herbs and spices you use to season it.

Like any cooking technique, there are simple mistakes that can lead to an unpleasant outcome. Whether you're preparing a pernod poached branzino or a turbot fish with pickled mushrooms, steer clear of these missteps to make sure you serve a deliciously poached fish.

There are many things to take into consideration when you're choosing a pan for poaching fish. First, it's crucial that your pan is large enough. If you're poaching individual pieces, a smaller pan may work, but you'll need a larger pan if you're poaching a large filet or a whole fish.

You also have to use a pan that can hold enough of your poaching liquid to cover your fish. It should be submerged to make certain it cooks properly. Getting the amount of liquid just right will produce well-poached fish and prevent you from making a mess. Keep in mind, too, that the poaching liquid will rise when the fish is added, and if you've added too much, it may spill over the sides. Choose a pan with high sides instead of a saute pan for best results. Whatever pan you select, make sure it has a lid that fits snugly enough to trap the steam that builds up inside. You'll need that steam to ensure your fish is cooked evenly and fully.

You can technically poach fish in any liquid. While water may be the most readily available, it's the least flavorful choice. Poached fish gets a lot of its flavor from the liquid you cook it in, so selecting a liquid that's rich in flavor will enhance the taste of your finished fish. When you're ready to amp up the flavor of poached fish, head to your pantry for a tasty option — for a delicious poached fish, you can swap the water for broth.

When you combine it with herbs, spices, and aromatics like onions or shallots, you can create a full-flavored broth for poaching with only a few simple ingredients. If you really want to level up your poaching liquid, take a tip from Julia Child and poach your fish in wine. White wines will add flavor and a bit of acidity without discoloring the fish. Feel free to experiment and use a combination of broth or water with a splash of wine to create your own perfect poaching liquid.

Poaching cooks fish in two ways: The hot poaching liquid heats the fish, while the steam that builds up in the pan when it's covered also contributes. Together, they produce fish that's moist, tender, and fully cooked. While you can technically poach fish in less water, making sure you add enough liquid to cover the fish will ensure your fish is not undercooked in the center when you serve it. If your poaching liquid doesn't completely cover the fish, you may need to flip it midway during cooking to ensure it's cooked through.

The goal with poaching is to use just enough liquid to cover the fish, and you need enough heat to bring it to a gentle simmer, not boil the fish. If your fish isn't fully covered, the exposed portion that rises above the water will likely cook, but it will lack the added flavor the poaching liquid imparts, and it may be drier than the submerged fish when it's done.

When you think of poaching liquid, water, wine, and broth might be the first things that come to mind, but there are other tasty options you should consider. Butter and olive oil are both great options for poaching fish. They each add a distinct flavor while ensuring your fish is exceptionally moist and tender. When you poach fish in butter, you get the added benefits of both a butter-infused fish and a delicious built-in sauce to serve with your fish.

Cooking food in olive oil is nothing new. The French confit technique involves gently simmering food in olive oil, but it's not the same as poaching. The difference between oil poaching and confit is simple. Confit uses less oil but requires more time, as the fish needs to be soaked in the oil overnight before being cooked. For olive oil poaching, avoid using expensive oils. Keep in mind you'll need enough oil to cover the fish fully, which could be a costly venture if you use a finer oil. Reserve those for other uses.

Poaching is a gentle cooking method that relies on a sustained simmer to cook your fish evenly, while at the same time keeping it moist and tender. If your poaching liquid is too cold, it won't cook the fish. On the other hand, if the liquid gets too hot and comes to a boil, it can not only quickly overcook your fish, but the rapidly moving bubbles can break thin, fragile pieces of fish apart. You'll end up with a fish soup instead of a deliciously poached filet.

When poaching fish for clients, I'd use an instant-read thermometer to check the temperature of the poaching liquid. Depending on the type of fish you're poaching and its size, the ideal temperature should be in the range of 140 to 160 degrees Fahrenheit. If your recipe doesn't specify a temperature or you're worried about overcooking the fish, stick with 140 degrees.

When you're cooking, it can be tempting to pile your pan high with food to cook it more quickly. Even when a recipe instructs you to cook food in batches, if you're short on time or just plain hungry, it's easy to add more food to the pan with the intention of speeding things up. This is a bad idea no matter what you're cooking, but especially when you're poaching fish.

Any time you add food to a pan, the temperature in the pan is reduced, so adding too much fish to poach means a lower temperature for the poaching liquid. To cook properly, you'll have to wait for the poaching liquid to return to its original temperature. By overcrowding the pan, you've inadvertently extended your fish's cooking time and increased the chance for it to cook unevenly. Follow your recipe's instructions on how much fish to poach at once, and if you're cooking without a recipe, make sure there's some space between each piece of fish. This will allow the poaching liquid and the steam it produces to circulate fully around each filet.

Poaching is a forgiving cooking method, making it difficult to ruin it by overcooking, but it's still possible. Fish should be poached just until it's done and no longer, but it can be difficult to tell when the fish is fully cooked when it's in a covered pot. You'll need to rely on the size of your fish and the temperature of the poaching liquid to get the timing right. A 1-inch-thick 6-7-ounce filet should be fully cooked after no more than eight minutes, while thicker cuts can take as long as 10 minutes.

Even after the recommended cooking time has passed, it's a good idea to check the fish for doneness before removing it from the poaching liquid. You can insert an instant-read thermometer into the center of the fish — when the internal temperature hits 140 degrees Fahrenheit, the fish is fully cooked. If you don't have an instant-read thermometer, you can gently drag a fork across the top of the fish. If it's fully cooked, the fork will easily separate the fish into flakes.

If you've prepared it correctly, poached fish is tasty on its own, but, like most foods, it's even better with a sauce. Serving poached fish with a sauce elevates the dish, making it refined and elegant enough to serve on special occasions. 

If you're butter-poaching your fish, the sauce is built in. The butter will have absorbed the flavor of any herbs, spices, or aromatics you added so you can spoon a little over the fish when you serve it. If broth, wine, or a combination of the two were your choice for a poaching liquid, you can put those to delicious use as a sauce, as well. Once the fish is removed from the liquid, return the pan to the stovetop. You can reduce the poaching liquid until it thickens for a simple sauce.

Any sauce that you would typically serve with fish will work with poached fish. You can create a complete, well-rounded dish by pairing poached fish with a simple tartar sauce or a flavorful dill sauce. Both of these can be prepared ahead of time so they're ready when your fish comes out of the poaching liquid.