A new supersaturation measurement technique is presented, based on forced encrustation of a cooled sensor surface. After a short discussion of aspects of the control of supersaturation, the measurement principle is introduced. The relationship between encrustation mass and crystallization heat on the one hand and supersaturation on the other hand is explained. As a main Feint of this presentation the technical realization of the supersaturation sensor are shown. The explanation of the innovative sensor technique is split into two parts. First, the technical construction is shown and second the detection and analysis of the measuring signal is presented. The integration of the sensor into a control strategy is possible or laboratory experiments. As the experimental results show, supersaturation measurement for systems with a small metastable zone width, such as KNO3, can be carried out in a reliable and accurate way. Furthermore, the universal applicability for various readily soluble solutes poses no problem.