The invention provides a process for the separation of lignins and sugars from an extracted liquor, comprising, in the form of dry matter (DM), lignins and sugars, characterized in that it consists in: a) concentrating the extracted liquor, in order to obtain a liquor comprising dry matter in a proportion of between 60 and 70%; b) mixing the concentrated liquor with water in equal parts by weight; c) stirring the mixture in order to disperse the lignins and to obtain a stable suspending of the lignins; d) filtering the solution, in which process: the mixing is carried out by introducing the concentrated liquor into the water; the temperature of the solution, during the suspending, is between 50 DEG C and 60 DEG C.