A brine is simply a seasoned salt-water bath that the turkey soaks in for 6-12 hours prior to cooking. The brine adds some flavor, but most importantly provides a chemical method to keep the meat tender and juicy while cooking.

Ingredients
Raw whole turkey
5-gallon bucket (like from Home Depot)
3-pound box of kosher salt
1 tablespoon of whole black peppercorns
2 gallons chicken broth (water mixed with bouillon cubes is fine
1-gallon ice water
1 whole bunch fresh thyme, torn roughly
1 whole bunch fresh oregano, torn roughly
1 whole bunch fresh sage leaves, torn roughly 
1 whole bunch fresh marjoram, torn roughly

To Make...

1. Clean the raw turkey and remove the neck and giblets.
2. In the bucket, combine the cooled (room temperature) broth with the ice water, salt, pepper and fresh herbs and mix well.

3. Place the turkey in the bucket, breast side down and cover the bucket. Leave it sit somewhere cool, I usually use the garage (unless it's summer time obviously).

4. After at least 6 and no more than 12 hours, and prior to cooking your turkey, remove the bird and rinse it with cool water, then proceed with your cooking prep