NOVELTY - Producing alcohol involves: providing biomass containing celluloses, hemicelluloses and lignin; contacting the biomass at 130-230 degrees C with aqueous solution of dilute acid in aqueous solution to biomass ratio of 2-10; separating at least a portion of the aqueous liquor from residual biomass; contacting pre-digested biomass stream with a cooking liquor comprising alkali (0.5-20 wt.%) selected from sodium hydroxide, sodium carbonate, sodium sulfide, potassium hydroxide, potassium carbonate, and/or ammonium hydroxide and water; washing; hydrolyzing; fermenting; and recovering alcohol.    USE - For producing alcohol from cellulosic biomass (claimed) e.g. ethanol, propanol and butanol used in fuel composition.    ADVANTAGE - The process allows for higher recovery of carbohydrate and thereby increased yields. The process is economical; inexpensive and easily recovers alcohol. By improving the digestion of biomass treatment and subsequent processing of such digested product, a process with high yield production of alcohol suitable for use in fuel is obtained. The process has significant benefits over other biomass pretreatments where the toxic components such as furfural and acetic acid are essentially eliminated for the fermentation process. The bulk removal of lignin allows improved mass transfer of enzymes to cellulose for conversion to fermentable sugars and lower equipment and energy requirements due to smaller volumes going forward. The process allows additional flexibility to treat a hemicelluloses rich stream to be converted to a fuel or chemical via different processing route more amenable to the chemical composition of this stream. The five-carbon sugars present in the hemicelluloses rich stream can easily be converted to furanic fuels via dehydration in high yields without fermentation that requires long residence times and hence high capital investments. The pre-digestion of the hemicelluloses allows to reduce the load on the recovery boiler in the pulp mill, thereby allowing to process increased capacity of feed and hence more fuel.    DETAILED DESCRIPTION - Producing alcohol involves: (a) providing a biomass containing celluloses, hemicelluloses and lignin; (b) contacting the biomass at a temperature of 130-230 degrees C with an aqueous solution comprising a dilute acid with concentration of up to 10 wt.% in an aqueous solution to biomass ratio of 2-10 thereby producing a predigested stream comprising an aqueous liquor comprising at least a portion of hemicelluloses and a residual biomass comprising celluloses and lignin; (c) separating at least a portion of the aqueous liquor from the residual biomass thereby providing an aqueous liquor stream and a pre-digested biomass stream; (d) contacting the pre-digested biomass stream with a cooking liquor comprising 0.5-20 wt.%, based on the cooking liquor, of at least one alkali selected from sodium hydroxide, sodium carbonate, sodium sulfide, potassium hydroxide, potassium carbonate, and/or ammonium hydroxide and water, at a cooking liquor to biomass ratio of 2-6, at a temperature of 60-230 degrees C to provide a digested biomass stream containing digested biomass containing cellulosic material, hemi-cellulosic material, and lignin, and a chemical liquor stream containing at least one sodium compound, potassium compound, or ammonium compound; (e) washing the digested biomass stream with a water stream thereby removing at least a portion of lignin and hemi-cellulosic material and producing washed digested biomass stream; (f) hydrolyzing the washed digested biomass stream by treating the streams with an enzyme solution comprising cellulases and optionally xylanases at a pH of 3-7 at a temperature of 30-90 degrees C to produce a hydrolysate containing 4-30 wt.% of fermentable sugar; (g) fermenting the hydrolysate in the presence of a microorganism at a temperature of 25-55 degrees C at a pH of 4-6 thereby producing an alcohol stream containing at least one 2-18C alcohol; and (h) recovering at least one of the alcohol from the alcohol stream and producing an aqueous effluent stream.