It involves the simultaneous mixing of a refrigerant such as liquid nitrogen (LIN) or liquid carbon dioxide (LCO2) and the product in a specially prepared unit. Product and cooling medium are loaded continuously at the highest entrance point of the drum. By the rotating movement, both are intensively mixed while, at the same time, sliding to the lower exit of the drum. The stirring movement and the mixing prevent products from clumping together. Special paddles can be built in to ensure this happens.