How to Poach Fish

Poached Mahi-mahi with Shrimp, Tomatoes and Baby Spinach

Poaching is an easy way to cook fish quickly. It’s a healthy alternative to frying, instead using a simmering liquid to cook the fish. Perfectly poached fish should unbelievably tender and melt in your mouth. With this easy technique, you can make sure that every time you poach fish it turns out perfect.

The trick to perfectly poached fish is to cook it gently and over low heat. The problem is that when people poach fish they will boil it until it turns tough and rubbery. Don't bring your pot to a boil, or even a simmer for that matter. Lower the heat. Fish is perfectly cooked when it reaches an internal temperature of 140 degrees. When you're poaching fish, you want the temperature of the water to remain at 140 degrees Fahrenheit. If you are familiar with sous vide cooking then this concept will ring a bell. Basically, if the water temperature never rises above (or much above) 140 degrees, then the fish will never overcook. Even if you leave the fish in the pan a little longer than necessary, the fish will remain perfectly cooked.

The poaching liquid in the pot will be at the right temperature when it starts moving around, and you see steam rising from the pot. You might notice 2 or 3 small bubbles rising, but no more than that. If the water is simmering, it is too hot. You'll also be able to dip your finger into the water very briefly without burning it.

Poaching fish may require a couple tries to get the timing and temperature right, but you’ll be glad you mastered it when you bite into that flavorful, perfectly moist fish.

Poaching usually has these four components:

Liquid
Herbs
An acid (lime, lemon, and vinegar)
A mixture of onions, celery and carrots

Traditionally, fish was poached in a court-bouillon, a clear broth made from simmering herbs and vegetables, together with something acidic like vinegar, lemon juice, or white wine.

If that sounds a bit tricky to you, there are many other ways of poaching that vary depending on what’s in your kitchen. The simp(Brian and I poached monkfish once and found it bland tasting. We used onion, garlic, and parsley in the poaching liquid and made a butter sauce with capers. We both thought it would be better pan or deep-fried.) lest method is just to use water as your liquid and add a little lemon juice, garlic, onions, herbs and spices or maybe some dry white wine, vinegar, broth and milk.

These are some good fish to poach:

Thicker, meatier fish such as salmon, trout, halibut and arctic char are best for poaching.

Mahi mahi
Barramundi
Arctic char
Dover sole
Halibut
Salmon
Tuna
Sturgeon
Turbot
Striped bass
Monkfish

Try whatever you like, but these varieties are among the most flavorful. Fish can be fresh or frozen. Fish steaks and whole fish are easier to poach than fillets, as they don’t crumble quickly. Sometimes even whole fish (usually the more delicate varieties) will curl or fall apart after poaching, but you can wrap your fish in layers of cheese cloth before poaching to avoid that.

Serving

Try topping your perfectly poached fish with a squeeze of charred lemon juice, some fresh dill or a little lemony hollandaise.

Velouté Sauce

If you plan to prepare a velouté from the cooking liquid, keep the fish covered and warm while you do the next step. Transfer about four cups of the poaching liquid to a separate saucepan. Reduce by about half, then whisk the resulting liquid into a simple butter-flour roux to make a velouté sauce. Sauce the fish and serve right away. Other ingredients can be added to the velouté to give it additional flavor. See Velouté Sauce