For cooks accustomed to checking a food’s internal temperature with a thermometer for safety, mussels oblige by springing open when they are ready to eat. Requiring minimal preparation, few ingredients and only a matter of minutes in the pot, mussels nevertheless deliver a sumptuous sensory experience.
Preparing the Mussels
Farm-produced mussels sold in supermarkets are purged in tanks after harvesting to expunge grit and impurities. As a result, store-bought mussels do not need to be soaked in water at home. If using wild mussels, though, soak for a couple of hours maximum in sea water, if available, or a bowl of cold water with sea salt dissolved in it. Adding cornmeal or cornstarch to the water encourages purging.
Clean the mussels by placing them in a colander and scrubbing each one under cold water with a brush to remove any debris. Although most commercially sold mussels already have the so-called "beard" mechanically removed, it can be easily cut away with a knife or tugged out with tweezers. Left intact, the beard is chewy but not harmful.
Discard any mussels that have cracked shells, and tap any mussels that are open on a hard surface. If they don’t close up by reflex, assume that they are expired and toss them.
Cooking the Mussels
Mussels cook in a matter of minutes and require little more than a few shakes of the pot along the way to heat them evenly. The classic approach, moules mariniere, from northern France’s Atlantic Coast communities steams the mussels in a high-sided pot, covered with a lid to seal in the heady aromas. The dish starts off by sweating some shallots and garlic in olive oil, before tossing in the mussels and a cup of water, beer, cider or white wine. Typically, the mussels will cook in the steam within three to six minutes, releasing their own sweet, briny juices as they do so. The mussels can be removed with a slotted spoon or tongs, and the remaining liquid finished into a velvety broth by adding cream, butter or stock. Any mussels that do not open should be discarded, however.
Working through a pile of mussels, using the empty shell of one to pull the meat out the others, is in itself a tactile pleasure, but attacking the broth with a hunk of crusty bread allows the flavors to show their quality, since mussels themselves taste quite neutral.
For a concentrated juice steeped in ocean aromas, steam the mussels in their own liquid in a hot, covered skillet, adding just a dash of lemon juice and butter to emulsify the juice. For stronger flavors, incorporate fennel or lemongrass for maximum aroma, Thai curry paste or chili flakes for heat, or coconut milk for a smooth, creamy finish.
To maximize the quantity of broth, boil mussels in a pan of coconut milk or stock, with plenty of aromatics, bringing the pot to a low simmer with the lid.on. The mussels will open as when steamed, at which point the pot can be removed from the heat.
Storing the Mussels
Fresh mussels should smell briny, whether farmed, wild, freshwater or saltwater. Most are sold in a mesh bag, at which point they are still alive. Ideally, mussels should be cooked as soon as possible after purchase, but they can be kept for a few days in the refrigerator, taking care not to let them become too cold or freeze. Proper storage should be in a bowl or colander covered with a damp cloth. Keeping them in plastic will suffocate them, while storing them in water can kill them. Mussels with a beard keep longer than those without, as removing it shocks the creature. For this reason, clean them just before cooking, not before storing. Once cooked, mussels will keep for up to two days in the refrigerator, ready to use in paella or salads, for example.