Knowledge of Material moisture in plastics in the production, storage and processing of plastics is of great importance. This necessary monitoring of the water content can be achieved throughout the complete process chain from granulation to silo storage using capacitive moisture sensors such as the DWF-RF-25. The water content is determined indirectly using this method. The equilibrium moisture in the immediate surroundings of the material is measured. The relationship between humidity and water content can be determined using the sorption isotherm or also pragmatically from the empirical values between humidity and water content.