The use of an adsorbent can be advantageous for the gentle drying of temperature-sensitive products. The used adsorbent binds water vapor and causes a driving force for drying to equilibrium, so that drying is possible also at low temperatures in the range of atmospheric pressure. The literature provides comparatively few data on drying of wet, especially biological products. The expected effects should be verified by experimental investigations with model substances and selected biological products. At the same time test methods and a test equipment should be established in order to be able to investigate various products in connection with different adsorbing agents with relatively little effort. For a physically based mathematical modeling of adsorption drying at low temperatures the water vapor adsorption isotherms of the products to be dried and the adsorbing agents at corresponding temperatures must be known. Therefore, they were determined experimentally and modeled mathematically.