U.S. Patent 6,931,758, assigned to Japan Tobacco Inc., Tokyo, Japan. An apparatus for carrying out a method of controlling the moisture of tobacco material comprises a hollow rotating cylinder having an inlet and an outlet for tobacco material, and a feeding device for supplying a moist air flow into the rotating cylinder such that the moist air flow runs out from the inlet toward the outlet within the rotating cylinder. Temperature and relative humidity of the moist air flow supplied into the rotating cylinder are within the range of 40-80 degrees Celsius and 80-95 percent respectively.