Why – and how – to eat mussels

The lowly mussel is making a comeback, for many good reasons. Mussels are tasty, cheap, and virtually guilt free – an increasingly rare quality among animal proteins.

The environmental consequences of meat are enough to give pause to most carnivores with a conscience. Cows fart and burp methane, which is 25 times more potent a greenhouse gas than carbon dioxide. Pig waste is polluting waterways. Nearly a third of the Earth’s ice-free land is devoted to the raising of animals for eating and milking – or to farmland on which animal feed is grown. Vegetarianism, many argue, is the only responsible way to eat. But we love our animal protein. Some say we need it.

There are loopholes in this vegetarian guilt trip. If you live in a place where animals are abundant enough to be hunted, you can eat wild game. You could eat bugs, of which there appears no shortage, although that’s not the kind of protein most people have in mind. Someday soon you might be able to sink your teeth into lab-grown meat, but today that option remains prohibitively expensive.

What does that leave us? Mussels, that’s what.

Mussels are one of the cheapest and tastiest forms of animal protein, and their environmental resume is impressive. They require no feed, as they filter algae, plankton and other microscopic nutrients from the water. Diseases are few, making the use of antibiotics virtually nonexistent.

And the fact that mussel shells are made of calcium carbonate means they absorb carbon from the environment. This is true of other shellfish as well, including clams, oysters, snails and scallops. But mussels contain the highest percentage of carbon of any shellfish. According to a 2011 paper published in the journal Marine Ecology Progress Series, shellfish and seaweed mariculture increase atmospheric CO2 absorption by coastal ecosystems.

But while mussels might be part of the solution to atmospheric carbon dioxide, they’re also victims of the problem. High CO2 lowers the pH of the oceans, making water more acidic. A Duke University study suggests that increased acidity takes a toll on oyster and mussel shells, weakening them and requiring more energy for the organisms to produce calcium carbonate. But, it’s also possible that mussels are trying to fight back. A study by the Woods Hole Oceanographic Institute found that in high ocean acidification some shellfish, including mussels, grow thicker shells.

However, a study published in Nature Climate Change and reviewed in Scientific American found that lower ocean pH saps the legendary strength of the mussel’s byssal threads, often referred to as “beards,” which connect them to the rock, ship or whatever substrate to which they are attached. If the mussels’ byssal attachments are weakened, they are more likely to fall off the rope when it gets pulled up (rope is the cultivation method most commonly used for mussels, in which the bivalves are grown on ropes dangling in the water.) Some mussels are grown on seafloor beds, a less desirable method because dredging is necessary to harvest them. This practice is disruptive to the ocean floor, according to Seafood Watch, which rates farmed mussels a “Best Choice,” and recommends seeking suspended culture mussels, which are the most common.

An order of mussels served in a wine sauce can be the most affordable meal option at many a restaurant. But before you place that order, it’s worth heeding the cautionary words of Anthony Bourdain, from his book Kitchen Confidential.

“I don’t eat mussels in restaurants unless I know the chef, or have seen, with my own eyes, how they store and hold their mussels for service. I love mussels. But, in my experience, most cooks are less than scrupulous in their handling of them. More often than not, mussels are allowed to wallow in their own foul-smelling piss at the bottom of the reach-in.”

All it takes is one bad mussel to ruin a whole meal. When cooking mussels at home, you can take precautions to avoid that one bad mussel, and these measures start at the store. If you notice a lot of open shells in the mussel pile behind the seafood counter, it might be an old batch, and perhaps mussels shouldn’t be in the cards that day. If you decide to go for it, make sure the fishmonger picks through them and removes any open ones, or mussels with broken shells. Smell them before you pay – they should smell like the ocean, not fish. Keep them cool until cooking time. 

For a simple preparation of the type that’s most commonly served in restaurants, start by sautéing a minced shallot and a few cloves of garlic in olive oil in a pot or deep pan. Add a half-cup of dry white wine and let it boil for a minute to evaporate the alcohol. I like to add a few cherry tomatoes here, but it isn’t necessary. Add your mussels and a handful of chopped parsley, and cook for about five minutes, covered, until the mussels all open. (Any mussels that refuse to open should not be eaten). Add another handful of parsley, mix it all around, and serve, jus and all, with bread. Eat it with an air of piousness. You are, after all, saving the world. Or at least you aren’t wrecking it as much as you could be.