NOVELTY - The method comprises, in a processing cycle: forming (A) a mixture comprising fresh water and a first fresh biomass; heating (B) the mixture at a first temperature and a first pressure for a first time period for forming a first liquid fraction and a first solid fraction; redirecting (C) at least a portion of the first liquid fraction from the first solid fraction, where the first liquid fraction comprises a product composition; and washing (E) the first solid fraction with a first wash liquor, where the first wash liquor comprises a wash liquor from a previous processing cycle.    USE - The method is useful for hydrolysis of biomass to maximize sugar yields comprising C5 saccharides.    ADVANTAGE - The method allows economical hydrolysis of the biomass.    DETAILED DESCRIPTION - The method comprises, in a processing cycle: forming (A) a mixture comprising fresh water and a first fresh biomass; heating (B) the mixture at a first temperature and a first pressure for a first time period for forming a first liquid fraction and a first solid fraction; redirecting (C) at least a portion of the first liquid fraction from the first solid fraction, where the first liquid fraction comprises a product composition; washing (E) the first solid fraction with a first wash liquor, where the first wash liquor comprises a wash liquor from a previous processing cycle, and the washing step comprises heating the first solid fraction and the first wash liquor at a second temperature and a second pressure for a second time period for forming a second wash liquor and a second solid fraction; removing (F) 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. The portion of the second wash liquor is used as at least a portion of the first wash liquor in the repeating step. A liquid comprising biomass hydrolysate is combined with fresh water to form the first wash liquor. The method further comprises: pressing the second solid fraction to obtain a third solid fraction and a third liquid fraction, where at least a portion of the third liquid fraction is used as at least a portion of the first wash liquor in the repeating step; and subjecting the second solid fraction to further treatment including hydrothermal treatment (preferred), acid hydrolysis, enzymatic hydrolysis and/or solvent extraction. The hydrothermal treatment comprises contacting the second solid portion with at least one fluid comprising supercritical fluid, near critical fluid, subcritical fluid and/or hot compressed water. The first temperature is 110-220 degrees C. The second temperature is 80-190 degrees C. The first time period is 10-140 minutes. The second time period is 20-120 minutes. The processing cycle has a total duration of 20-240 minutes. The first pressure is sufficient to maintain any water present in liquid form. The processing cycle produces a product composition with an increased level of C5 saccharides relative to a batch processing cycle without the redirecting, washing, removing, and repeating steps. A weight ratio of total water added during the method to dry biomass is less than 10. One of the first fresh biomass and the second fresh biomass is subjected to steaming prior to the forming step. An INDEPENDENT CLAIM is included for a system for hydrolysis of biomass.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of a method for hydrolysis of biomass.    Forming a mixture comprising fresh water and a first fresh biomass (A)    Heating the mixture (B)    Redirecting at least a portion of the first liquid fraction from the first solid fraction (C)    Washing the first solid fraction with a first wash liquor (E)    Removing portion of the second wash liquor from the second solid fraction. (F)