One of the most representative crops which can be cultivated in extensive surfaces worldwide is represented by vine. Grape marc is produced in large quantities in wine production with the issue of disposal being an important environmental consideration. The main problem in energy recovery from this type of biomass is represented by its high content of moisture and therefore the necessity of a pre-treatment process before valorization. In this paper the bio-drying process was chosen for the increase of calorific value of exhausted grape marc. The main parameters and their influence on the process are presented in this paper.