Abstract: A fluid bed dryer comprises a pre-dryer of the back mixed type and a post-dryer of the plug flow-type. In the pre-dryer the main part of heat is transferred to the product being dried by means of heating panels arranged above the bed plate. A control bed is interposed between the pre-dryer and the post-dryer and includes one or more temperature sensors for sensing the temperature of the product in the control bed. Heat supply to the heating panels is controlled in response to the temperature sensed by the sensor or sensors in order to maintain the product temperature in the pre-dryer at the dew point and so as to ensure that the drying process proceeds within the region of constant drying rate, and that the product contains little or substantially no unbound moisture despite possible changes in product fed to the pre-dryer.