NOVELTY - Deconstructing and extracting (M1) sugar molecules involves: a) mechanically disintegrating the biomass in the presence of water and under pressure, to produce liquid, vapor, and solid disintegrated biomass; b) separating liquid and vapor from solid disintegrated biomass; c) contacting disintegrated biomass with acid to depolymerize polymeric carbohydrate component to produce acid impregnated disintegrated biomass; d) feeding the biomass into digestor; and e) separating liquid hydrolysate comprising hemicellulose sugar molecules and residual solids containing cellulosic fiber.    USE - For deconstructing and extracting sugar molecules (preferably mannose, xylose, glucose, arabinose, or galactose) from biomass containing cellulose and hemicellulose (where the biomass is lignocellulosic material selected from softwood or hardwood, and the lignocellulosic material is in the form of wood chips); for extracting hemicellulose sugar molecules for producing hydrolysate, which is useful for producing a bioproduct selected from biofuel (preferably butanol, ethanol, or acetone) (all claimed), solvent (e.g. polar protic or aprotic solvent), biomolecule, organic acids, alcohols, fatty acid, aldehyde, lipid, long chain organic molecule, vitamin, and sugar alcohol.    ADVANTAGE - The method enhances the extractability of soluble sugar molecules from biomass material. The method reduces the impact of wood extractives on bioproduct e.g. biofuel, production and process production (i.e. prevents pitch deposits) by reducing or excluding extractives from the hydrolysate produced from a biomass feedstock. The method permits hydrolysate to be prepared under less harsh process conditions (e.g. reduced acid concentration and reduced temperature). The lower acid concentration and reduced temperature (lower steam pressure) provides a cost benefit and improved yield. The method provides a higher productivity (higher throughput, with associated cost benefit) than other known approaches.    DETAILED DESCRIPTION - Deconstructing and extracting (M1) sugar molecules from biomass containing cellulose and hemicellulose, involves: a) mechanically disintegrating the biomass in the presence of water and under a first pressure, to produce liquid and/or vapor and solid disintegrated biomass; b) separating the liquid and/or vapor from the solid disintegrated biomass, where step (b) can be performed after or in conjunction with step (a); c) contacting the solid disintegrated biomass with acid in an amount to depolymerize a polymeric carbohydrate component of the biomass, to produce impregnated disintegrated biomass; d) feeding the acid impregnated disintegrated biomass into a digestor through a pressure changing device, where the acid impregnated disintegrated biomass is heated under a second pressure in the digestor at a temperature and for an amount of time to permit the depolymerization reaction to occur, where a composition is produced that comprises a liquid hydrolysate and residual solids; and e) separating the liquid hydrolysate and residual solids, where the liquid hydrolysate comprises hemicellulose sugar molecules and the residual solids comprise cellulosic fiber. INDEPENDENT CLAIMS are included for the following:    (1) a deconstructed biomass material from which hemicellulose sugars have been extracted and which optionally retains visible cellulosic fiber having at least 0.35 mm in length, where the material is prepared according to the method (M1);    (2) a conditioned hydrolysate (H1) produced according to the method (M1); and    (3) producing a bioproduct involving culturing a microorganism that produces the bioproduct in a medium that comprises a conditioned hydrolysate (H1) under conditions for production of the bioproduct.