The invention provides a process for controlling the moisture content of a supply gas for use in drying a product, which process comprises the steps of: (a) providing the supply gas; (b) optionally heating the supply gas; (c) determining the temperature and the moisture content of the supply gas; (d) contacting the supply gas with a rotating desiccant wheel, whereby the rotating speed of the desiccant wheel is controlled by means of the data on the temperature and the moisture content as obtained in step (c) in combination with the corresponding sorption isotherm of the desiccant; and (e) recovering the dehumidified supply gas as obtained in step (d). The invention further provides a dehumidified gas obtainable by said process, a dehumidifier system, a process for drying a product comprising bringing the product into contact with a dehumidified gas as obtained in accordance with the invention, and a product obtainable by said drying process.