NOVELTY - Hydrolyzing biomass comprises in processing cycle e.g.: forming mixture comprising fresh water and first fresh biomass; heating mixture at first temperature and first pressure for first time period, thus forming first liquid fraction and first solid fraction; redirecting at least portion of first liquid fraction from first solid fraction; washing first solid fraction with first wash liquor; removing at least portion of second wash liquor from second solid fraction; and repeating processing cycle using second fresh biomass in place of first fresh biomass.    USE - The method is useful for hydrolyzing biomass.    ADVANTAGE - The method provides high yield of sugar including 5C saccharides.    DETAILED DESCRIPTION - Hydrolyzing biomass comprises in a processing cycle: forming a mixture comprising fresh water and a first fresh biomass; heating the mixture at a first temperature and a first pressure for a first time period, thus forming a first liquid fraction and a first solid fraction; redirecting at least a portion of the first liquid fraction from the first solid fraction, where the first liquid fraction comprises a product composition; washing the first solid fraction with a first wash liquor, optionally where the first wash liquor comprises a wash liquor from a previous processing cycle, the washing comprises heating the first solid fraction and the first wash liquor at a second temperature and a second pressure for a second time period, thus forming a second wash liquor and a second solid fraction; removing at least a portion of the second wash liquor from the second solid fraction; and repeating the processing cycle using a second fresh biomass in place of the first fresh biomass. An INDEPENDENT CLAIM is also included for a system, comprising a batch digester (11), comprising a first end (12), a second end (13), and a heating device (14), a wash liquor tank (15) in fluid communication with the first end of the batch digester, a product tank in fluid communication with the second end of the batch digester, and a press in fluid communication with the second end of the batch digester.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of the system.    Batch digester (11)    First end (12)    Second end (13)    Heating device (14)    Wash liquor tank (15)