Salt is a remarkable ingredient in cooking. Aside from its distinctive flavor, its unique chemistry means you can also use it to preserve meats or simply make them juicier when cooked. Both goals require brining your food -- soaking it in a high concentration of salt. Serious preservation or curing requires a long time in the salt, but you can make your chicken juicy and flavorful with a much quicker, simpler brine.
The science of brining is complex and still somewhat debated, but the end result is clear. If you soak your chicken in water with a high concentration of salt, it absorbs some of that salt water. When you roast a chicken, that water mostly leaves the bird, but -- and it's an important but -- the chicken's own juices mostly don't. That leaves it moister and more flavorful, even if you have the misfortune to over-cook the chicken somewhat.
Making a Quick Brine
Most brine recipes call for you to mix a quantity of coarse or sea salt -- not table salt, which adds a chemical flavor -- with sugar, spices and various other ingredients. A good ratio is 2 tablespoons of coarse kosher salt for every 2 1/2 cups of water, with other ingredients to taste. You simmer them together to dissolve the salt and diffuse the flavors, then chill the brine overnight, and immerse the bird or the cut of meat in the refrigerated brine for another several hours. This isn't especially difficult, but it's inconvenient if you've just decided you want chicken tonight.
Food writer Michael Ruhlman offers a brilliantly simple solution on his blog. Heat up a very concentrated brine, then pour it over a large quantity of ice. The ice melts, chilling and diluting the brine, and can be used immediately. Pour the brine into a heavy-duty bag with your chicken, and pop it into the fridge until you're ready to cook. Two to four hours is ideal for a whole chicken, but even 30 minutes helps. If you cut the chicken into pieces, 30 minutes might be all you need.
If even this relatively quick brine takes more time than you've got, just whisk about 1/4 cup of salt into a quart of cold water and go with that. It's decidedly better than nothing.
Another option is dry-brining. Instead of dissolving the salt in water, simply sprinkle it liberally all over your chicken, inside and out. After an hour or two, at minimum, brush off the salt and roast the bird.
Dry-brining doesn't fill the chicken's muscle fibers with extra moisture. Instead it draws out a small portion of its natural juices, dissolves, and is then drawn back into the tissues. As an added bonus it dries the chicken's skin, helping it roast to a beautiful golden brown.
Brines often include some sugar, which softens the taste of the salt and is absorbed in much the same way. Simmering pepper and other spices into the brine can impart some extra flavor to the chicken, but you can just add them later if you don't have enough time to heat and cool the brine. Some cooks use broth, wine or citrus juice in their brines -- essentially making it a salty marinade -- but despite its compelling logic, it's a bad ideal in real-world use.
If your chicken is described as seasoned or pre-seasoned, it was brined at the packing plant. Don't brine those again, or you'll end up with an inedibly salty bird.