Abstract: A method for drying a wet material, which comprises a liquid Fd to be distilled, uses a gas-tight container system resistant to excess and/or negative pressure and a drying container, a condenser and a vapor chamber connecting the drying container and condenser. The temperature adjustable drying container contains the wet material. The liquid Fd is turned to vapor in the temperature adjustable vapor chamber. The condenser condenses the vapor to give the condensation product. The pressure in the vapor chamber is monitored and controlled so that drying and distillation are always carried out in a range close to the saturation vapor pressure of the liquid Fd to be distilled. The pressure and the temperature in the vapor chamber are continuously determined. If the pressure goes above the upper limit of the range, the pressure is reduced in such a manner that especially foreign gas is removed.