Salting vs. Brining?
From America's Test Kitchen - article no longer available
In the test kitchen, we're strong advocates of brining--soaking meat in a solution of salt and water before cooking. The meat absorbs water as well as salt, with the latter helping the meat retain the moisture as it cooks. With our Spice-Rubbed Picnic Chicken, however, brining made the skin soggy. To solve this problem, we turned to salting the chicken overnight, which helped the meat retain moisture as it cooked--and didn't harm the skin.
Chicken naturally contains some salt and lots of water, which coexist in a happy balance. In coating the chicken with salt, we threw off that balance. To restore order, or equilibrium, water in the meat moved to the surface, where it dissolved the salt.
But wouldn't drawing all that water out of the chicken make the situation worse, causing the meat to dry out? It certainly did--until we figured out the timing. When we tried cooking chicken that had been salted for three hours, the chicken cooked up drier than if we hadn't salted it. (The juices that had made it to the exterior simply evaporated in the oven.) But when we cooked the chicken after six hours, the story changed entirely. By that point, the exterior salt had pulled so much water to the surface that the balance of the salt concentration had changed. To restore equilibrium, the water simply changed directions, flowing back into the meat. But this time--and here's the key--the dissolved salt went along for the ride. Essentially, we had "brined" the chicken using its own juices instead of a bucket of water.
Once we successfully tapped into this means of delivering salt to the interior, we wondered if it was possible to deliver other flavors the same way. As it turns out, it all comes down to whether the flavoring agent is water-soluble (like salt) or fat-soluble. With the rub we used for our Spice-Rubbed Picnic Chicken, the salt and brown sugar, which dissolve easily in water, flowed right in, as did some of the distinguishing flavor compounds of the black pepper, cayenne, chili powder, and paprika. But the spiciness was waylaid at the surface. Capsaicin, the compound that gives chile peppers their spicy heat, is soluble only in fat, so it was unable to join the caravan. -S.W.