Salt Cod 101
Why would we eat salt cod when we can have fresh fish?
The answer is flavor. When white fish is saturated with salt and dried, amino acids and other chemical changes occur in the fish. This produces a chewier texture and milder, almost sweet, yet still fishy taste than its fresh counterpart. It's not unlike how fresh pork can be transformed into ham. It's the same but different and both are wonderful.
What Is Salt Cod?
Salt cod came from our forebears' innovation: they needed a way to eat year-round, fish was plentiful, and a means of preservation was invented.
Its history goes back to the Vikings, but many countries, especially ones that share a coast with the Atlantic, have some culinary connection with salt cod. In Italy it's called baccalà, bacalao in Spain, morue in France, bacalhau in Portuguese, bakaliaro in Greece, saltfish in the Caribbean, and klippfisk in Scandinavian countries.
For centuries, cod was hugely plentiful in the cold northern Atlantic sea. Because there was lots of it, it was cheap, and being cheap, it became a food for the poor. The fish would be salted and put out in the sun to dry, afterwards keeping for months. Salt cod also shares a history with the slave trade as it was a food preserved for the long ship journeys from Africa to the Americas where it became a food for slaves on southern plantations.
Today the cod has been severely over-fished and according to the Monterrey Bay Seafood Watch, some, including ones caught by trawler, should be avoided. For this reason and also for its cost, some producers have switched to salting other kinds of white fish. But not all cod is verboten and in most New York-area stores, salted cod is easily available, selling for about $10 to $12 a pound.
I'm still trying to get my head around Nathan Myrhvold's new $625, 5-volume and 40 pound Modernist Cuisine, which seems to me has more to do with Mr. Myrhvold's amusements and food chemistry than it does with cooking and eating. But still, many of his 2,400 pages make the case that smart use of science, whether it's sous vide (cooking vacuum-sealed food in a water bath) or salting fish, has the potential of producing a flavor or an ingredient that can become mainstream.
Cooking With Salt Cod
If you're unfamiliar with salt cod but maybe see boxes of it in fish stores and fish departments, you may think it's a recipe for a heart attack. It's not. That's because before we cook and eat it, the salted fillets are soaked in repeated baths of cool water for about 24 hours to remove most of the salt. (If you are strict in avoiding salt in your food, check with your doctor or nutritionist first about whether it's advisable to eat desalinated salt cod because some sodium will remain in the fish, in amounts that are similar to smoked trout or salmon.)
Before cooking with salt cod, place it in a large bowl in the sink and fill the bowl with cool water, covering the fish entirely. About an hour later, dump out the water and refill the bowl again with more fresh water. Repeat this process for the next 24-hours, leaving the fish to soak for increasing periods of time and making sure you've changed the water at least 4 times. You'll notice as you go through these steps how the salt will be leaving the fish -- first from its surface and then from the fish itself. The fish will also absorb some of the water and take on weight so that a fillet that may have weighed 12 ounces to begin with will be about a pound by the time you're done.
The pieces of salted cod often have bones, which are easy to remove after the fish has been completely soaked.
You can also make your own salted cod. Buy fresh cod, cut it into large chunks and rub the pieces all over with generous amounts of kosher salt, about 3 tablespoons per pound. Wrap the fish pieces in plastic, pressing the wrap against the surface of the fish to remove surrounding air, and refrigerate for 24 to 48 hours. Then soak and desalinate before cooking with it.
Far from tasting like you've swallowed a mouthful of seawater while swimming at the beach, desalinated salt cod is very mild. Because it had been salted and preserved, it is already "cooked" and is treated differently in recipes than if it were fresh fish. It also is tougher than tender flakes of raw cod, and this, too changes how it is used in recipes.
Salt Cod Recipes
My favorite way to cook with and eat salt cod is also one of my all-time favorite dishes -- it's even on the menu for my last supper. And on those very lucky times when I score a trip to Paris as I did last year, my first meal must always be at Le Bon Saint-Pourcain, a little restaurant tucked behind Saint Sulpice where I will dig into a large plate of Brandade de Morue. (Update: c'est dommage but the restaurant has closed.)
This classic French dish originated in Provence and is a purée of salt cod, garlic confit, olive oil, and mashed potatoes. Purists say leave out the potatoes, but I think they lost that argument a few centuries ago. The flavor is nutty from the potatoes and butter-soft garlic, slightly unctuous from the olive oil, and faintly fishy from the cod. It's usually served with olive oil slicked slices of toasted baguette spread with creamy Garlic Confit (see our recipe).
Below we've added a link to a recipe from chef Riad Nasr of Balthazar Restaurant produces a Brandade de Morue that is exactly like that served at Le Bon Saint-Pourcain. It can be paired with a salad to become a main course, or instead be a starter or spread on baguettes and passed as an hors d'oeuvre. I personally just use a soupspoon and happily make it my dinner.
If in the unlikely case you have any left over, you should use it to make Bacala Croquettes. We love the recipe at Food52.com from Jennifer Hess at LastNightsDinner.net.
Other popular salt cod dishes include fish cakes, piquillo peppers stuffed with salt cod purée, salt cod soufflés, and in St. Croix, little pocket pies are stuffed with salt cod. In Spain, Bacalao al Pil-Pil is a traditional dish from Spain's Basque region that is served with an aioli-like sauce (aioli is similar to mayonnaise but made with garlic and olive oil).
You can buy salt cod at most fish mongers and the fish departments at our better markets.