Meats with less fat contain dense muscle fibers that are surrounded by proteins. As food is heated, these proteins and muscle fibers will contract which pushes moisture out and also makes the meat tougher. Therefore, meat loses weight as it cooks, and overcooked meat becomes tougher to chew. Brining allows salt to break down cell walls in the proteins and those cells are then able to take on extra water through osmosis. This can add additional water weight prior to cooking which counterbalances the amount of water weight lost while cooking. Salt also dissolves the protein filaments which prevents them from tightening and makes the meat more tender. The additional salt also adds seasoning to the inside of the meat creating better flavor throughout.
Flavor can also be added in the form of herbs and spices. Sugar can also be used to balance the salt, but finding the right balance can be hard to figure out, so many prepared brines such as Sweetwater Spice Co. brines and Cattleman’s Grill Butcher House Brine take the guesswork out of brining. Just add the brine mixture to water and soak for the recommended amount of time and then you are ready to season the outside and cook.