NOVELTY - Method for treating lignocellulosic biomass, involves (a) introducing a liquid stream and feedstream in a pre-soaking vessel, (b) pre-soaking the feedstream with liquid stream, (c) separating at least a portion of liquid stream from the solids to create a first solids product stream and pre-soaked liquid product stream, and (d) (i) soaking the first solids stream in vapor or liquid water or their mixture, and (ii) separating at least a portion of the soaked liquid from the second soaked biomass to create a soaked liquid stream and a second solid stream.    USE - The method is useful for treating lignocellulosic biomass chosen from plant biomass chosen from refined starch, bagasse, wheat straw, and polysaccharide containing biomass.    ADVANTAGE - The method is cost-effective, and consumes minimal time.    DETAILED DESCRIPTION - Method for treating lignocellulosic biomass, involves (a) introducing a liquid stream comprising water and feedstream comprising lignocellulosic biomass solids containing cellulose and sugars in a pre-soaking vessel, (b) pre-soaking the feedstream with liquid stream at 100-150 degrees C, (c) separating at least a portion of liquid stream from the solids to create a first solid product stream and pre-soaked liquid product stream, and (d) (i) soaking the first solid stream in vapor or liquid water or their mixture at 100-210 degrees C for 1 minute-24 hours to create a second soaked biomass comprising dry content and soaked liquid, and (ii) separating at least a portion of the soaked liquid from the second soaked biomass to create a soaked liquid stream and a second solid stream, where the second solid stream comprises the second soaked biomass, or performing the above-mentioned steps, (e) separating at least a portion of the soaked liquid from the suspended solids of the soaked liquid stream comprising monomeric sugars, oligomeric sugars, acetic acid, and furfural, and (f) filtering at least a portion of the acetic acid from the at least a portion of the soaked liquid to create a permeate and a retentate.