Abstract: A method and apparatus for size reduction of a material. The method includes the steps of: feeding material through a feed assembly into a cyclone chamber, the cyclone chamber having an elongate cylindrical conduit having a frusto-conical section; adding at least one viscosity modifying agent into the cyclone chamber; and providing a cyclonic fluid stream within the cyclone chamber. The apparatus includes: a cyclone chamber having an elongate cylindrical conduit having a frusto-conical section; a device for creating a cyclonic fluid stream within the cyclone chamber, such that the frusto-conical section of the cyclone chamber terminates in an opening forming the inlet to the device; an air inlet tube in fluid connection with the cyclone chamber at the opposite end of the frusto-conical section; and a feed assembly for feeding material into the cyclone chamber.