Mussels and clams – species of which are so varied and numerous that placing them in a single family remains controversial – are often lumped together, despite being quite distinct. Both are bivalves, as are oysters and scallops. They secrete their own shells out of calcium carbonate, expanding it to accommodate their growing selves. (The human equivalent would see us enlarging our childhood rooms at will, as we bloom into adolescence and adulthood.) Mussels, which tend to cluster on marine cliffs and river shores, are easily grown on longlines, in tubular nets or, more anciently, on ocean rafts. Almost the entire global production comes from aquaculture, much of it from China. Most mussels, however, are consumed in Europe, and some are produced there too.
Unlike mussels, clams are infaunal animals, that is, living in sediments. They too may be cultured, but to a lesser extent, and with generally longer farming cycles. When harvested wild, clams need digging out individually from the sandy seabed: they are, all told, considerably pricier than mussels.
In much of the world including parts of the Mediterranean, clam-digging was customarily women’s business, often entailing hardscrabble wages. The sector remains intensely gendered in Tunisia, a country that counts some 4 000 women digging at nearly 20 sites. Here, around the coastal cities of Gabès and Sfax, FAO has been working with the clam-diggers’ association to cut out exploitative middlemen and link the women directly to importers. The price paid to the diggers is higher and guaranteed; they also receive a premium for only picking the larger clams, which makes for a more sustainable supply. Training in handling and food safety is part of the package.
The main clam markets all have their preferences, driven by access to native species. In the United States of America, these will often be the hard-shelled quahogs of Rhode Island, famed as the stuff of chowder; in Japan, the colourful Manila clams, used in a clear, cleansing broth called ushio-jiru; in Spain, razor clams, which pair felicitously with warm olive oil and garlic, but equally well with jamón and toasted almonds; in France, the palourdes with their yellow glow, slick with butter and parsley; and in Italy, the darker vongole, tossed with spaghetti in a reduction of garlic, chilli and white wine, the whole enriched by the addition – wholly optional – of guanciale, or pig’s cheek bacon. Swine and clams also click happily in porco à Alentejana, the Portuguese laurel-scented land-and-sea stew.
Mussels are, by comparison, a straightforward, economical affair. While arguably less varied or versatile, they’re no less enjoyable than clams, frequently fleshier and sporting a springy chewiness. Mussels are also richer in iron and lower on sodium, should you be watching your salt intake. Their even plumpness is a repeatable joy – and the fun of using one valve to scoop the mollusc out of the other will get the children hooked.
You will need to soak your clams in cold salted water for up to four hours in advance, during which time they should expunge any sand they hold. Bubbles will form in the water; change it once or twice. If a lot of sand is released, throw each clam lightly against the side of the kitchen sink to force out the last grains. When you’ve done this, scrub the clams – still in cold water – if they appear to need it. We offer a recipe that marries clams with fish, crab and other crustaceans: you can find it here. Since mussels are overwhelmingly sourced from aquaculture, they will generally come prerinsed, with no need for soaking. Still, running them under cold water, and maybe giving them a quick scrub, will remove any extant sand or grit. Finally, you may have to yank off the “beard,” technically known as byssus. (These wispy strings, once prized as sea silk for use in textiles, are secreted by the animal to bind it to its habitat.) As with all bivalves, discard any open mussels, or those that don’t open up when exposed to heat. And mind that you don’t keep them long: mussels spoil faster than clams. Our two mussel recipes come from the northern and southern hemispheres. Both are frank comfort food, as anything involving mussels should be, but differently so. One is firmly in the continental Atlantic tradition. The other melds Indigenous influences with modern US and Japanese ones.