The objective of this paper was to determine sorption qualities of food concentrates on the basis of an analysis of sorption isotherms. The analysis results obtained were discussed from the point of view of the durability and ability to rehydrate of the products analysed. The study included the determination of initial water content in the material analysed USING a method of thermal drying under the atmospheric pressure. The sorption qualities of the two types of products were investigated with the use of a static method by selecting sorption isotherms within the water activity range from 0,07 to 0,98. The sorption isotherms selected underwent a BET transformation within the range of 0,07-0,44; the V_m capacity of monomolecular layer and its corresponding water activity were calculated; also, a specific surface of sorption was determined. It was proved that the initial water content in the concentrates under analysis depended on both the chemical composition of product and the employed technology. The sorption isotherms of products investigated corresponded to type III according to the Brunauer’s classification. The capacity of monomolecular layer and the specific surface of sorption, its derivative, depended on the chemical composition of product. A significant affinity among some parts of products analysed and water might indicate their satisfactory rehydratability. Additionally, a high volume of the monomolecular layer may favourably impact the storing durability of products.