The process of grinding of wheat grain endosperm leads to damage of the starch fraction. Starch damage in wheat flour changes its water absorption. Intact starch absorbs water in the amount of 70% of its mass, and damaged granules have up to 3-fold higher level of absorption, which is conditioned by the increased number of small crystalline structures and damage to many crystalline structures. These changes cause an increase of the volumetric water absorption capacity and it can be assumed that this will be reflected in the surface microstructure of starch particles that affect the adsorption of water vapour. The aim of the study was to evaluate the impact of comminution of gluten-free wheat starch on the adsorption properties of its granules. The study included the determination of adsorption isotherms of water vapour at 20°C with the static-desiccator method and the determination of adsorption parameters and microstructure of starch granule surface based on the GAB and Kelvin equations. The results confirmed the positive impact of mechanical processing on the capacity of surface water vapour adsorption by starch granules and this was indicated by a significantly diversified distribution of adsorption isotherms, surface adsorption parameters and parameters of microstructure of molecules on which adsorption was tested.