Conche

A conche is a surface scraping mixer and agitator that evenly distributes cocoa butter within chocolate, and may act as a 'polisher' of the particles. It also promotes flavor development through frictional heat, release of volatiles and acids, and oxidation. There are numerous designs of conches. Food scientists are still studying precisely what happens during conching and why. The name arises from the shape of the vessels initially used which resembled conch shells.