TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The method further comprises: adding one or more fermentation organisms to the saccharification product; maintaining the saccharification product under suitable conditions to promote fermentation of sugars produced by hydrolysis to produce a fermentation product; adjusting the pH of the first or second prehydrolysate to a pH of 3-9 prior to the spraying step; mixing the pretreated biomass composition with the second prehydrolysate liquid; and moving the impregnated biomass composition with a belt or screw conveyer into a reactor for the hydrolysis. The pretreated biomass solids are not rinsed or conditioned before spraying with the second prehydrolysate. The pretreated biomass solids are transported on a screw or a belt conveyer during the spraying step to form the impregnated biomass composition. The pretreated biomass solids are ground up prior to spraying with the second prehydrolysate liquid. The pretreated biomass composition is produced from: an acid sulfite or acid bisulfite pretreatment process; an alkaline sulfite or alkaline bisulfite pretreatment process; and a neutral chemical pretreatment process or a pretreatment process using water and no additional chemicals. The hydrolysis produces a sugar yield of 80-100% of the pretreated biomass composition. Preferred Components: The liquid further comprises one or more fermentation organisms, where the fermentation organisms ferment sugars produced by the hydrolysis to produce a fermentation product. The saccharification enzymes comprise cellulase, beta -glucosidase, xylanase, and/or other hemicellulases. The fermentation organisms comprise yeast, mold, algae, and/or bacteria. The pretreated biomass composition comprises wood chips, where the wood chips are size reduced prior to pretreatment, such that prior to size reduction 50-100% of the wood chips pass through a +7 mm round hole screen, and after size reduction, 50-100% of the wood chips pass through a +3 mm round hole screen. The fermentation product has a titer of greater than 4%. The fermentation converts 60-100% of the sugars to the fermentation product. EXAMPLE - Yeast seed was first grown in a complex medium containing yeast extract (1%), peptone (2%), and glucose (3%). The stock seed culture was incubated at 38 degrees C and 200 revolutions per minute. The yeast seed culture was centrifuged and dissolved in sodium citrate buffer (100 mmol). The yeast seed was inoculated at 2 g/liter dry cell weight in the fermentation tests. Corn steep liquor (4%) and urea (0.11%) were added to the fermentation medium. Pretreated pulp and prehydrolysate were sterilized separately in an autoclave at 121 degrees C for 20 minutes before fermentation. The simultaneous saccharification and fermentation was initiated by adding the pretreated pulp (14%), liquor (full strength), yeast seed (2 g/liter), corn steep liquor (4%), cellulase (16 g ), beta -glucosidase (20 units/g pulp), and xylanase (9 U/g pulp). After all the ingredients were added, the initial mixing was completed by a vigorous mixing until all the pulp materials showed a homogeneous wet slurry. The total pulp materials and the prehydrolysate occupied 80.7% of the total fermentation volume and the rest 19.3% volume was from enzymes, nutrients, and yeast seed. Fermentation in shake flasks was controlled at 38 degrees C and 150 revolutions per minute. Fermentation pH was controlled at pH 6.5 by a 50 mmol sodium citrate buffer and by periodic pH checking and readjustment. The ethanol production was complete in 48 hours, and an ethanol concentration of 4.4% was achieved.