The article considers the influence of nanoscale objects on grain raw materials processing on the example of beer wort preparation. The effect of aluminum oxide nanoparticles present in the mash on the first wort indicators (concentration of dry and reducing substances, amine nitrogen) obtained by infusion or single-decoction mashing was studied. It was revealed that the influence of Al2O3 nanoparticles depends on their concentration, the object of influence and the method of preparation of beer (first) wort. The most sensitive to the presence of aluminum oxide nanoparticles under the experimental conditions were saccharifying hydrolases of grain raw materials. That caused the greatest fluctuations in the concentrations of reducing substances in the test samples of the first wort. Nanoparticles had the least pronounced effect on grain proteases, as a result fluctuations in the concentration of amino acid nitrogen in the experimental variants of the first wort were the smallest. When obtaining beer wort by the infusion method, the effect of nanoparticles was more pronounced than in single-decoction mashing. The concentrations of aluminum oxide nanoparticles were revealed, the excess of which led to a significant deterioration in the controlled parameters of the first wort - 1.5-2 mg/cm3, depending on the method of mashing.