Method and system for gasifying biomass. Tar loaded gas from the reactor for gasifying the biomass is subjected to a saturation and absorption treatment with a first and second fluid respectively. The first fluid comprises aromatic hydrocarbons whilst the second fluid comprises linear hydrocarbons. Tars received in the aromatic fluid is entered together with such fluid in a separation column. Separation is effected based on evaporation temperature and the lighter fraction is returned to the inflow of the saturation separator. The heavier fractions are either discharged or sent back to the biomass reactor. An intermediate buffer vessel can be provided between the discharge of the saturation cleaner and the separator.