The invention relates to a method and system for processing biomass. The method includes a device having a housing, a rotor inside the housing and a plurality of projections extending out from the rotor the method likewise includes placing the biomass in a fluid medium, inducing cavitation in the fluid to partially separate the biomass, pushing the biomass and the fluid toward the inside of the housing, making the rotor spin to further separate the biomass, heating the biomass and the fluid and maintain the acidity of the fluid and the biomass at a pH of approximately 2 to 6. The system includes a device, each one having a housing and a rotor inside the housing. One device has adjacent projections of alternate heights extending out from the rotor another device has notches in the rotor and a housing end wall and yet another device has two rows of projections extending out from the rotor, with separations of at least approximately 6 millimeters.
