Methods and processes for the production of valuable organic products and alcohols from biomass material using a closed-loop process having numerous advantages over prior production methods are described. In the process, the biomass is subjected to acid-catalyzed digestion, followed by a separation of the digestion product stream into a solid product stream and a liquid product stream, the liquid product stream thereafter undergoing acid-catalyzed dehydration in the presence of an organic solvent, and thereafter separating the organic products in the organic layer from the aqueous layer. During the process, aqueous and organic fluid streams are fed back into various portions of the production process to increase the concentration of active portions and maximize product recovery.