In one embodiment, the invention is to a process for purifying a crude ethanol product. The process comprises the step of hydrogenating acetic acid in a reactor in the presence of a catalyst to form the crude ethanol product. The process further comprises the step of separating at least a portion of the crude ethanol product in a purification zone. The purification zone preferably comprises a first column, which yields a first distillate comprising ethanol, water and ethyl acetate, and a first residue comprising acetic acid. The at least a portion of the crude ethanol product has a residence time from the reactor to the purification zone from 5 minutes to 5 days.