Colloid mills are widely used in the food industry to homogenize medium and high viscosity liquids. A colloid mill usually contains two disks: a rotor (a rotating disk) and a stator (a static disk). The liquids to be homogenized are usually fed into the center of the colloid mill in the form of a coarse emulsion, because the device is efficient at reducing the size of the droplets in a preexisting emulsion. The rapid rotation of the rotor generates a shear stress in the gap that causes the larger droplets to be broken down into smaller ones, and generates a centrifugal force that causes the fluid to move from the center to periphery of the disks. Colloid mills are more suitable for homogenizing intermediate and high viscosity fluids such as peanut butter, fish, or meat pastes.