In this work, the fractionation of grape seeds as a model biomass was studied using a combination of two processes: solvothermal extraction and hydrothermal fractionation-hydrolysis process in a semicontinuous reactor. First, grape seeds were subjected to an extraction process with ethanol/water (70/30wt.%) at 90°C during 60min obtaining ca. 13.0wt.% of oil and extractable components with 4.46wt.% of polyphenols (66% of the maximum). Afterwards, the solvent was water and the biomass was treated in steps at different temperatures (150°C to 340°C). During the hydrolysis the pH decreased from 5.5 down to 3.0 due to acetyl group liberation. The total quantity of recovered sugars varied around 20.0 to 23.1wt.%. The best experimental condition for obtaining the maximum amount of pentoses+hexoses+oligosaccharides was 180°C (45min)+250 to 265°C (45min)+330 to 340°C (45min).