The article presents data on acidity indicators and chemical composition of high humidity grain in hermetic storage conditions. It is established that by increasing humidity of barley grain fodder its acidity increases with increasing pH value from 5.25 to 4.13, which is explained by increasing content of lactic and acetic acids. During storage the grain did not deteriorate, because the pH value decreases to a certain level (from 5.25 to 4.13). No butyric acid was found in the examined samples and its appearance was not observed during the whole storage period. The content of other acids (lactic acid, acetic acid), as well as their percentage ratio were in optimal quantities, which corresponds to the normative requirements for feeding farm animals. Most of the acids were lactic acid, whose share was 86-93% depending on grain moisture. As the humidity of wheat grain increases, its acidity also increases with the introduction of various additives in the amount of 3% of the mass of raw materials. The number of mineral macro- and microelements in grain slightly increases in comparison with the control variant, which is caused by their higher content in additives. The main part of mineral elements was occupied by potassium, the quantity of which was from 6,53 (variant: mixture of needles and moss, 2%) to 7,93 mg (variant: nettle, 3%). In variants with the use of the studied plant additives, there is a tendency to increase the content of raw protein from 10.72% in the control without additives to 12.72% in variants with meadow grass and 12.84% in variant with pine needles.