When talking about fish, the term poaching is used most often for fish cooked in a simmering liquid where the liquid is intended to be discarded. Braising or stewing is often used when the liquid is to be served with the fish.
The water used when poaching fish should be "high quality". If you don't drink your tap water, then don't use it for this recipe. Use water that you would be willing to drink (and, hopefully, prefer the taste of) for this recipe because those off flavors will present themselves in the final dish if you use funny tasting water. Also, we're not going to boil the fish - we're going to cook it in near boiling temperature water. Boiling will cause unnecessary violent currents through the cooking liquid which will end up tearing apart the fish into little pieces instead of gently cooking them through. The poaching liquid can be used repeatedly for multiple batches of fish or other foods you may want to poach in a flavorful liquid - just bring it back to a boil between uses. (Use the poaching liquid all in one session and then discard... please don't keep a pot of poaching liquid sitting on your stove waiting for the next poached fish meal.)
I find that tilapia, red snapper, and bass seem to work well when poached. But it greatly depends on the individual: the flavors of catfish may be pleasant to many, but I can't stand it when poached. Each fish has it's own flavors, so I encourage trying them out (in a restaurant or when they go on sale) and figuring out what flavors agree with your palate. Poaching is a great way to prepare fish for tasting, because the flavor of the fish is not overwhelmed by sauces or marinades.
Bring the poaching liquid back up to a full rolling boil, then turn the heat back to the lowest setting. When the boil settles down, place the fillets into the liquid with a thin, flat, slotted spatula and cover for five minutes. (Filets thicker than 1 cm may need an additional minute or two.)
Poached Fish
Poaching liquid
Drinking water | pour in large pan until 1 in. (2.5 cm.) deep | add | bring to boil | reduce heat to low | simmer 20 min. |
1/2 cup dry white wine | |||||
30-40 black peppercorns | |||||
2 garlic cloves | |||||
1 bay leaf | |||||
4 parsley sprigs |
Poached Tilapia (serves 4)
Poaching liquid | boil | reduce heat to low | cover & poach 5 min. | discard |
8 3 oz. (85 g) tilapia filets | plate & garnish | |||
Salt | ||||
Extra virgin olive oil | ||||
1 Tbs. (9 g) capers | ||||
1 lemon | cut into 8 wedges |