The Chez Panisse "Cafe Cookbook" brine recipe doesn't call for one to boil the salt/spice mixture before cooling it and submerging the meat, but many brine recipes and products do. I can't find scientific explanation for this variation in technique in McGee or any of the cookbooks that litter my house. Does anyone know why some chefs boil their brine and some don't?
Boiling and cooling the brine adds many hours to what is already a fairly long process, so if that can be omitted without loss of flavor, well, great.
My own tests lead me to believe that the flavors of the spices actually tend to cook out and disappear during boiling. In the no-boil Chez Panisse recipe the flavors of bay, clove and thyme come through loud and clear in the roasted pork/chicken.