FISH - COOKING METHODS
Since fish is so delicate it has to be really cooked with care. Some fish can be overcooked within seconds, but there are ways to tell when the fish is cooked properly (we discussed this earlier on our other pages). Now, let's cover some of the most common techniques for cooking fish and how to bring out the best of them.
Frying
The goal when frying a fish is usually to get a crispy surface and retain the moisture in the flesh. The worst thing that can happen is that the meat will become very firm and rubbery. To avoid this, fish fillets are often salted to draw out some of the water in the fish and bring it to the surface, and then coated in flour or other ingredients that will promote quick crispiness in the heat. The fish is fried in high heat in a little olive oil, and it can be finished off with some butter for more flavor. When frying fish with skin on, the skin is not coated with anything nor salted as it becomes crispy by its own inner nature. Remember also that once the crispiness is there, it can be destroyed by excessive moisture, so don't sandwich the fish in-between other fish or ingredients that could provide moisture to the crisp surface.
The amount of heat is determined by the thickness of the fish. To get a crisp surface AND a moist interior, you need to balance the heat against time and thickness of the fish fillet. Thinner fillets are browned and cooked faster and best at high heat, while the thicker fillets will brown too quickly on high heat, before the inner parts of meat are cooked. Therefore, for bigger fillets use lower heat instead. Or, brown it first, and if the interior is not finished then put it in a hot oven to get it done. Fish usually cooks within a few minutes on each side, and you can follow the progress by looking at how the opacity of the flesh diappears from bottom to top as the proteins become denatured. Turn the fish around to the other side when the progress reaches halfway. Use residual heat to cook the last few milimiters of the fish.
A more fool-proof method to cook fish is to coat it in some batter (e.g. tempura) and deep fry the fish. The batter will brown quickly and function as a partial heat insulator so that the fish meat inside will cook more gently.
Baking
Baking fish is a popular method to use since the heat is entering the fish fairly gently (since the air is an inefficient heat conductor) and the fish is less likely to get overcooked. Of course, the fish still has to be checked so it doesn't overdry! The nice thing behind hot oven air is that it leads to evaporation of fish water that is partially retained on its surface, so it provides some cooling against the hotness. In this way, fish juices and other ingredients of the dish can become more intensive and the fish retains lots of its moisture.
Fish can be baked wrapped into a paper or a foil (en papilotte) which will make it even more moist since lots of water is retained within the baking compartment. Fish can also be steamed in an ordinary fashion in a steamer, and it's important that the steam gains access to all the surfaces of the fish.
Poaching
A simple method to cook fish is by putting it into a hot liquid (poaching). Since water conducts the heat very effectively, the fish cooks very quickly. The liquid is usually very simple, like water or milk, since the fish doesn't pick up very many flavors during the short time it is cooked. One can however cook it on lower heat in a liquid that has been pre-made and stuffed with aromatic ingredients (herbs, vegetables, wine). Poaching is conducted in gentle heat, and the fish can be wrapped into a plastic foil to make the cooking even more gentle and to retain its flavors inside.