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Fish & Seafood - Fish Essentials

DK Publishing logoDK Publishing 2/07/2014 DKBooks

Cooking fish en papillote—in a parcel—is another gentle method of cooking fish fillets. Traditionally the parcel is made out of squares of parchment paper, but you can also wrap the fish in foil or banana leaves. Salmon fillets are particularly good cooked in this way, but cod and halibut are also suitable. Fish fillets can be packaged up with vegetables, herbs, a little white wine, or butter and must be tightly sealed to keep in all the flavors and the all-important steam. Cook them in an oven at 475°F (240°C) for 15 minutes, depending on the thickness of the fillets.

Fish Essentials

There are several key points to consider when choosing fish to buy. Sight, smell, and touch are needed to assess the quality of fish, and you need to know what to look for in order to determine which are the best-quality specimens. For optimum flavor, fish should be bought and cooked as fresh as possible, preferably when in season—you will find many fish species are interchangeable in recipes. Certain species are suffering from overfishing, so the sustainability of the fish should also be given consideration. If you are buying fish in advance of serving it, it is important to store it properly to keep it at its best.


Choose the freshest, best-looking fish available—one that has a bright eye and smooth, glistening skin. There are particular signs of quality all over the body of a fish, in this instance a brook trout, that are worth knowing before you buy.


These should be bright, convex, and black with a translucent cornea. As a fish loses condition the eyes look sunken, the pupil appears gray or milky, and the cornea opaque.


On a whole fish these should be bright and glistening and firmly attached to the skin. Scales that look dull and dry and that are easily detached indicate that the fish is no longer fresh and should be avoided.


The skin of a gutted fresh fish should look bright with evenly distributed surface slime that appears clear and colorless. Fish that is decomposing will have lost shape and the color may have faded. The slime will also have become sticky and discolored.


Good-quality fresh fish may still show signs of rigor mortis (be stiff and rigid). This indicates that it has been out of water for no more than 24–48 hours. Once there are no signs of rigor, a good-quality fish should feel firm and elastic to the touch and the flesh should be firmly attached to the backbone. Pressing along the back of the fish is often the best place to check for firmness. Once the fish loses condition it will be soft and flabby, tears easily from the backbone and will “pit” on pressure.


A fresh fish should either have no smell at all or should smell pleasantly of the sea, with no underlying offensive aroma. Fish that are beginning to decompose will smell stale, sour, and strong.


A fresh, gutted fish has bright red gills. As the fish loses condition the color fades to brown and the mucous becomes sticky.

Endangered fish

World fish stocks are suffering from the effects of overfishing, with some stocks near collapse and species facing extinction. Governments are imposing quotas and even outright bans to tackle the problem, but consumers can play their part, too. Check where a fish has come from and whether it has been fished sustainably; line-catching is better than nets or trawling, since it avoids unwanted by-catch and smaller fish are left behind to maintain the stocks. Instead of choosing an old favorite try something new: consider coley and pollack in place of endangered cod. And take farmed fish seriously: though it’s not without issues, farms take pressure off wild stocks.


Ideally fish should be purchased on the day you intend to cook it, but if you have to store it for a short period of time, proper preparation and conditions are essential for ensuring its quality and also its safety. You can store fish in the refrigerator for up to 24 hours, but if you intend to use it after that time, it is better to freeze it on the day of purchase.

Storing fish at home

The temperature of a domestic refrigerator is usually set at around 40°F (5°C), but fish should be stored at 32°F (0°C), so when storing fish in the refrigerator at home it is important to place it in the coldest part or to surround it with ice. Pack whole fish into ice and place fillets in containers set on ice. The process of commercially freezing fish is done efficiently and quickly at very low temperatures, but it is difficult to replicate this at home. Freeze fish in small quantities in double-layered freezer bags, with as much air extracted as possible and carefully sealed. Freeze the fish for no longer than 4–6 weeks.

Fresh vs. frozen

Many fish are processed and frozen at sea for an ever-expanding market. Freezing fresh fish slows the changes that occur as spoilage takes place and, if carefully done, it can be impossible to tell the difference between fresh and frozen. Fish labeled as “frozen at sea” will have been processed and frozen within a few hours of being landed, and so the flavor is often superior to fresh fish. Fish should always be defrosted before cooking. This should be done slowly, in a refrigerator—rapid defrosting can result in loss of moisture, which will ruin the fish’s texture.


You can buy fish already prepared, but it will not be as fresh as buying a whole fish. The amount of preparation required before cooking a fish depends on how you intend to cook it. Whole fish generally need gutting, trimming, and scaling before cooking, or you might prefer to skin and fillet it or cut it into steaks.

Gut a whole round fish

This essential job requires you to remove all the viscera from the stomach of the fish, usually via a cut in the belly.

Place the fish on to its side and make a shallow incision into the underside of the fish. Cut along the belly, from the tail all the way up to the head.

Remove the guts of the fish and with the back of the knife loosen the membrane that covers the blood line located close to the back bone. Scrape this blood line away.

Rinse the inside of the fish carefully under cold running water and wipe away any gray membrane left in the belly cavity. Pat the fish dry with paper towels, inside and out.

Why is my fish gutted?

Some fish are gutted on landing because the guts are the first part of the fish to decompose. The belly (abdominal walls) of an ungutted fish should be smooth and show no signs of tearing. As the fish loses condition the abdomen will look blown, and as the belly tears, the guts will be visible. Some fish, including mackerel, herring, sprats, trout, and sea bass are left ungutted. Ungutted fish should be cleaned as soon as possible.

Trim and scale

If you are intending to eat the skin of the fish, you will need to trim away any fins and remove the scales for finer eating.

Using scissors, remove all fins. Cut from tail to head for ease, trimming them level to the skin. Remove the tail fin after the scales, as it provides something to hold onto during scaling.

Using the back of a knife or a fish scaler, scrape the scales on each side of the fish in sweeping actions from the tail to the head, against the direction in which the scales lie.

Skin a fish fillet

Once you have deboned the fish, you can remove the skin from the fillet before cooking.

Place the fish skin-side down with the thinnest part toward you. Hold the tail tip and, using a filleting knife, place the knife against your fingers, angled toward the skin.

Cut between the skin and the flesh in a firm sawing motion. Continue to move the knife along the length of the fillet, keeping the blade as close to the skin as you can.

Cut steaks from a whole fish

Fish steaks are a versatile cut that are quick and easy to cook, particularly when broiled. This technique can only be used on large round fish, not small or flat specimens. Fish such as salmon, tuna, and swordfish are particularly good for cutting into steaks. The skin is left on steaks but the fish should be gutted, washed, scaled, and trimmed of any fins before being sliced.

Place the prepared fish in front of you with its back toward you. Make an incision just behind the gills with a large sharp knife, and cut through to remove the head.

Section the fish into steaks of even thickness using the same knife, at 11/2in (4cm) intervals down to the anal vent. Fillet the tail piece, since this is too thin to steak.

Fillet a small round fish

Small round fish (such as mackerel or the red mullet shown here) can be quickly grilled, pan-fried, or poached when trimmed into two neat fillets.

With the back of the fish facing you, make a cut behind the head and the pectoral fin using a sharp filleting knife. Stop when you feel the backbone, then angle the knife to cut toward you and lift the fillet from the bone.

Remove the cut-away fillet and set aside, then turn over the fish, this time placing the head of the fish toward you. Repeat the process on the other side, but cut from the tail up to the head.

Fillet a flat fish

A flat fish can be cut up into either two fillets or, if it is a particularly large fish, like this turbot, four fillets. The fish needs scaling, the head and gills removed, and trimming before filleting.

Lay the fish flat with the tail facing you. Insert the tip of a filleting knife at the top of the backbone—the top of the bone should be visible—and make a cut along the center of the fish.

Angle the knife slightly so that the tip moves over the bones of the fish, then insert it under the fillet. Carefully move the knife down to the edge of the fillet to release it at the fins.

Turn over the fish and lay it flat again, repeating the same process on the other side of the fish to create four fillets. Once you have removed the fillets, you can skin them, if you wish.

Tools of the trade

Sharp knives are essential for preparing fish. Ideally, you need a large cook’s knife with a 10in (25cm) blade for tougher jobs such as chopping and cutting fish steaks, whereas a flexible-bladed filleting knife makes light work of filleting fish and removing skin. A fish scaler is easier to use than a knife when removing scales. Sharp kitchen scissors are useful for trimming fish and removing fins. Fish tweezers are the most efficient tool for removing pin bones from fillets.


Fish is the ultimate fast food and most fish fillets take less than 20 minutes to cook. The muscle structure of the fish is such that quick methods of cooking suit it particularly well.


This is the most familiar way to cook fish and is best used for cooking small, prepared, and crumbed fish fillets, or larger fish, such as a whole salmon. Preheat the oven to 375°F (190°C) and lightly grease a baking tray with melted butter or oil.

Arrange the fish side by side on the prepared baking tray, season the fillets and add a splash of oil or butter, or brush with oil infused with freshly chopped herbs.

Bake in the oven for 4–6 minutes, depending on the thickness of the fillets. Gently insert the tip of a sharp knife to see if the fish is cooked through—the flesh should be opaque.


Suitable for cooking whole small fish (the fish needs to be turned halfway through cooking) or smaller fish fillets—ideally with the skin on, as this will protect the fish from drying out. Preheat the grill to its highest setting for a few minutes before cooking the fillets.

Lightly score the skin of the fillets using a sharp knife. Brush the fillets with a light coating of oil (or a marinade), and season with a little salt and freshly ground black pepper.

Grill for 4–5 minutes, depending on the thickness of the fillets. Turn the fish over halfway through cooking. Remove the fish and allow to stand for 1–2 minutes before serving.


This method is suitable for fillets of fish or small whole fish. The fish is fried in a smaller amount of oil than deep frying, usually using grapeseed or canola oil, and crisps up on the outside while staying moist on the inside. Pan-fried fish is especially good when coated in flour, breadcrumbs, or cornmeal before frying.

Pat the fish fillet dry with paper towels to remove any excess moisture. Coat the fish with seasoned flour, breadcrumbs, or cornmeal on both sides, then shake off any excess.

Heat 1–2 tbsp of butter with a splash of oil until the butter has melted and is beginning to brown. Put the fish in the pan and cook for 1–2 minutes, until golden brown.

Turn the fish over and continue to cook on the second side for a further 1–2 minutes. Remove from the pan, drain briefly on paper towels, then serve immediately.


Suitable for delicate fillets or steaks of fish, particularly white, textured, and smoked fish. Poached fish retains a good moisture level and the cooking liquid can then be used in a sauce, or for a stock or soup base. This method is intended for the stovetop, but fish can also be poached in the same liquid in an oven set to 350°F (180°C).

Use a poaching liquid of lightly acidulated stock or infused milk. Cover the fish with the cold liquid and bring it slowly just to a boil.

Once the liquid has reached a boil, reduce the heat immediately to a gentle simmer and cook for 10–15 minutes until done.

Carefully remove the fish from the liquid in the pan; do not let it break up. Serve dressed with the poaching onions and herbs.


This gentle, healthy method of cooking is suitable for very small whole fish, fillets, or steaks of fish. Fish for steaming can be seasoned before or after cooking and cooked with flavorings such as herbs, scallion, and citrus slices. Any liquid produced can be served with the fish or used in an accompanying sauce. All you need is a pan with a lid and a steaming rack that fits inside.

Choose a saucepan with a well-fitting lid to ensure the steam is trapped. Pour in just enough water so that it doesn’t touch the base of the steamer. Add any preferred aromatics to the water. Arrange the fish in a single layer in a bamboo or metal steamer basket.

Put the pan over medium heat and bring to a simmer. Place the steamer into or over the pan of liquid. Ensure that the liquid is kept at a constant boil to enable the fish to cook quickly. Don’t lift the lid as this allows the steam to escape and lengthens the cooking time.

How to tell when fish is cooked

All cuts of fish take different times to cook.

Raw fish has a translucent appearance that turns opaque and lighter in color after cooking.

A fish cooked whole and with its head on has various indicators: eyes turn white after cooking, the skin will pull away, and the fins can be easily pulled out.

A fish fillet will lose its translucency and, if gently pressed, the flakes of the fish will separate. If the fish is poached in a simple, clear liquid, you can see protein released just at the point when it is cooked.

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