How Are Peanuts Salted Inside the Shell?
Peanuts are salted inside the shell by soaking them in brine, then drying them by roasting, leaving a salt residue behind on the nut in the shell. Sometimes a vacuum is used to remove air from the batch before the brine is introduced.
Peanuts are often salted to improve their flavor. To salt peanuts while they are still inside the shell, whole peanuts are put into a sealed, pressurized tank that is filled with salt water.
The pressure in the tank forces the salty water inside the porous shells, salting the peanuts. The salted peanuts are dried and then roasted to bring their rich, nutty flavor. Roasting dramatically changes the peanut composition.
Raw peanuts are pea like in flavor until they are roasted. In fact, peanuts are not actually nuts. They are the seeds of a plant closely related to peas-hence the name, peanut.