A process for increasing alcohol yield from biomass (the form or agro- or forest residue, grains, hops, etc.), involving multiple hydrodynamic cavitation treatments of biomass filtrate—both before and after fermentation. Carbohydrates extracted from biomass are subjected to a first cavitation treatment to promote additional conversion into carbohydrates. The carbohydrates are then combined with bacterial species and nutrients, and allowed to ferment. The fermentation product is subjected to a second hydrodynamic cavitation treatment to promote further conversion of carbohydrates into bioalcohol. After distillation, the bioalcohol is subjected to a second hydrodynamic cavitation treatment to increase its purity.