A device is provided for determining the water content of a target (1), the device having at least one source of target radiation (2), at least one source of reference radiation (4) directed to a target surface (10), and at least one detecting element (3) for measuring the intensity of radiation reflected back by the target surface. During use the at least one source of target radiation (2), the at least one source of reference radiation (4), and the at least one detecting element (3) are arranged immediately opposite the target surface (10). A pressurizing device using air or gas is provided, by which an artificial movement of the air or gas atmosphere can be created in the area of the optical paths between the at least one source of target radiation (2) and the target surface (10), and/or between the at least one source of reference radiation (4) and the target surface (10), and/or between the target surface (10) and the at least one detecting element (3).