Think of a protein strand as a loose coil with water molecules bound to its outside surface. When an unseasoned protein is heated, it denatures: the coil tightens, squeezing water molecules out of the protein matrix, leaving the meat dry and tough if overcooked. By disrupting protein structure, salt prevents the coil from densely coagulating, or clumping, when heated, so more of the water molecules remain bound. The piece of meat remains moister, and you have a greater margin of error for overcooking.
This same chemical process is the secret to brining, the method in which a piece of meat is submerged in a bath of water spiked with salt, sugar, and spices. The salt in this mixture, or brine, dissolves some of the proteins, while the sugar and spices offer plenty of aromatic molecules for the meat to absorb. For this reason, brining can be a great strategy for lean meats and poultry, which tend to be dry and even bland. Make Spicy Brined Turkey Breast, and you’ll see how a night spent in a salty, spicy bath will transform a cut of meat that’s often devastatingly dry and flavourless.
I can’t remember the first time I tasted—consciously, anyway—meat that had been salted in advance. But now I can tell every time I taste meat that hasn’t. I’ve cooked thousands of chickens—presalted and not—over the years, and while science has yet to confirm my suspicions, I’ll speak from experience here: meat that’s been salted in advance is not only more flavourful, it’s also more tender, than meat that hasn’t. The best way to experience the marvels of preseasoned meat for yourself is with a little experiment: the next time you plan to roast a chicken, cut the bird in half, or ask your butcher to do so for you. Season one half with salt a day ahead. Season the other half just before cooking. The effects of early salting will be apparent long before the first bite hits your tongue. The chicken salted in advance will fall off the bone as you begin to butcher it, while the other half, though moist, won’t begin to compare in tenderness.
When salting meat for cooking, any time is better than none, and more is better than some. Aim to season meat the day before cooking when possible. Failing that, do it in the morning, or even in the afternoon. Or make it the first thing you do when collecting ingredients for dinner. I like to do it as soon as I get home from the grocery store, so I don’t have to think about it again.
The larger, denser, or more sinewy the piece of meat, the earlier you should salt it. Oxtails, shanks, and short ribs can be seasoned a day or two in advance to allow salt time to do its work. A chicken for roasting can be salted the day before cooking, while Thanksgiving turkey should be seasoned two, or even three, days in advance. The colder the meat and surrounding environment are, the longer it will take the salt to do its work, so when time is limited, leave meat on the worktop once you season it (but for no longer than two hours), rather than returning it to the fridge.
Though salting early is a great boon to flavour and texture in meat, there is such a thing as salting too early. For thousands of years, salt has been used to preserve meat. In large enough quantities, for long enough periods of time, salt will dehydrate meat and cure it. If dinner plans change at the last minute, a salted chicken or a few pounds of short ribs will happily wait a day or two to be roasted or braised. But wait much longer than that, and they will dry out and develop a leathery texture and a cured, rather than fresh, flavour. If you’ve salted some meat but realise you won’t be able to get to it for several days, freeze it until you’re ready to cook it. Tightly wrapped, it’ll keep for up to two months. Simply defrost and pick up cooking where you left off.
Seafood
Unlike meat, the delicate proteins of most fish and shellfish will degrade when salted too early, yielding a tough, dry, or chewy result. A brief salting—about fifteen minutes—is plenty to enhance flavour and maintain moisture in flaky fish. 2.5cm -thick steaks of meatier fish, such as tuna and swordfish, can be salted up to thirty minutes ahead. Season all other seafood at the time of cooking to preserve textural integrity.
Fat
Salt requires water to dissolve, so it won’t dissolve in pure fat. Luckily, most of the fats we use in the kitchen contain at least a little water—the small amounts of water in butter, lemon juice in a mayonnaise, or vinegar in a vinaigrette allow salt to slowly dissolve. Season these fats early and carefully, waiting for salt to dissolve and tasting before adding more. Or, dissolve salt in water, vinegar, or lemon juice before adding it to fat for even, immediate distribution. Lean meat has a slightly higher water (and protein) content—and thus, greater capacity for salt absorption—than fattier cuts of meat, so cuts with a big fat cap, such as pork loin or rib eye, will not absorb salt evenly. This is illustrated beautifully in a slice of prosciutto: the lean muscle (rosy pink part) has a higher water content, and thus can absorb salt readily as it cures. The fat (pure white part), on the other hand, has a much lower water content, and so it doesn’t absorb salt at the same rate. Taste the two parts separately and you’ll find the lean muscle unpleasantly salty. The strip of fat will seem almost bland. But taste them together and the synergy of fat and salt will be revealed. Don’t let this absorption imbalance affect how you season a fatty cut. Simply taste both fat and lean meat before adding more salt at the table.
Eggs
Eggs absorb salt easily. As they do, it helps their proteins come together at a lower temperature, which decreases cooking time. The more quickly the proteins set, the less of a chance they will have to expel water they contain. The more water the eggs retain as they cook, the more moist and tender their final texture will be. Add a pinch of salt to eggs destined for scrambling, omelettes, custards, or frittatas before cooking. Lightly season water for poaching eggs. Season eggs cooked in the shell or fried in a pan just before serving.
Vegetables, Fruits, and Fungi
Most vegetables and fruit cells contain an undigestible carbohydrate called pectin. Soften the pectin through ripening or applying heat, and you will soften the fruit or vegetable, making it more tender, and often more delicious, to eat. Salt assists in weakening pectin.
When in doubt, salt vegetables before you cook them. Toss vegetables with salt and olive oil for roasting. Salt blanching water generously before adding vegetables. Add salt into the pan along with the vegetables for sautéing. Season vegetables with large, watery cells—tomatoes, courgettes, and aubergines, for example—in advance of grilling or roasting to allow salt the time to do its work. During this time, osmosis will also cause some water loss, so pat the vegetables dry before cooking. Because salt will continue to draw water out of vegetables and fruits and eventually make them rubbery, be wary of salting them too early—usually 15 minutes before cooking is sufficient.
While mushrooms don’t contain pectin, they are about 80 percent water, which they will begin to release when salted. In order to preserve the texture of mushrooms, wait to add salt until they’ve just begun to brown in the pan.
Legumes and Grains
Tough beans: a kitchen fiasco so common it’s become an idiom. If there’s one way to permanently turn people off of legumes, it’s serving them undercooked, bland beans that are hard to eat. Contrary to popular belief, salt does not toughen dried beans. In fact, by facilitating the weakening of pectins contained in their cell walls, salt affects beans in the same way it affects vegetables: it softens them. In order to flavour dried beans from within, add salt when you soak them or when you begin to cook them, whichever comes first.
Legumes and grains are dried seeds—the parts of a plant that ensure survival from one season to the next. They’ve evolved tough exterior shells for protection, and require long, gentle cooking in water to absorb enough water to become tender. The most common reason for tough beans and grains, then, is undercooking. The solution for most: keep simmering! (Other variables that can lead to tough beans include using old or improperly stored beans, cooking with hard water, and acidic conditions.) Since a long cooking time gives salt a chance to diffuse evenly throughout, the water for boiling grains such as rice, farro, or quinoa can be salted less aggressively than the water for blanching vegetables. In preparations where all of the cooking water will be absorbed, and hence all of the salt, be particularly careful not to overseason.
Doughs