Hydrothermal digestion of cellulosic biomass solids may produce a glycol reaction product for subsequent processing. Methods for digesting cellulosic biomass solids to form and process a glycol reaction product may comprise: providing cellulosic biomass solids and a slurry catalyst in a hydrothermal digestion unit, the slurry catalyst being capable of activating molecular hydrogen; heating the cellulosic biomass solids in the hydrothermal digestion unit in the presence of the slurry catalyst, a digestion solvent, and molecular hydrogen, thereby forming a liquor phase comprising soluble carbohydrates; performing a first catalytic reduction reaction on the soluble carbohydrates within the hydrothermal digestion unit, thereby at least partially converting the soluble carbohydrates into a reaction product comprising a glycol; at least partially drying the reaction product, thereby forming a dried reaction product comprising a dried glycol; and at least partially converting the dried glycol into a monohydric alcohol external to the hydrothermal digestion unit.