Although lignin in plant tissue is supposed to protect the interior of the cell wall from water penetration and technical lignins (except for lignosulfonates) are not water-soluble, lignin is nevertheless able to adsorb water on its surface. The hygroscopic character of lignin is caused by the presence of individual hydrophilic sites on the surface of the macromolecule, where the greatest contribution to hygroscopy is made by the hydroxyl (aromatic and aliphatic) and carbonyl groups . The hygroscopic properties of kraft lignin can have a decisive influence on the performance and stability of lignin-based polymers and must therefore be investigated. Since DVS measurements in our setup require a considerable amount of time (2-3 days/sample), only the original sample that underwent the extraction process and the 60-minute samples of the different test series were selected and characterised.