Agrotechnical measures effect on the composition and quality of dry white wine from pervenets Magaracha grape variety

The aim of research is to study the effect of the load of bushes with shoots on the physicochemical composition and organoleptic properties of wines from the Pervenets Magaracha grape variety. Tasks: to carry out physical and chemical analysis and organoleptic evaluation of experienced dry white wines. The objects of research are wort and wines from the white technical grape variety Pervenets Magaracha grown in the vineyards of ARRIV&W experimental field. The study was carried out on the basis of the laboratory for quality control of wine-making products and the laboratory of wine-making technology of ARRIV&W, a branch of FSBSI FRASC. The grapes were processed according to the following variants of experiments: B-1 - load of 30 shoots/bush; B-2 - 35; B-3 - 40; B-4 - 45 shoots/bush. Experienced wines were prepared under the conditions of micro-winemaking according to the classical technology for dry white wines. The results of the chemical analysis of the wort showed that an increase in the load of the bush with shoots and, accordingly, the yield contributed to a decrease in the mass concentration of sugars and nitrogenous substances. The content of the sum of phenolic substances in the wort of the test samples fluctuated in the amount of 245-309 mg/dm3, their highest content was noted in experiment B-2 (309 mg/dm3). The content of volatile acids was in the range of 0.48-0.61 g/dm3 and did not exceed the standardized limits (for white dry wines - up to 1.1 g/dm3). In the process of vinification in all the tested wines, there was a decrease in the concentration of total and amine nitrogen by more than 50 % due to the use of nitrogenous substances by yeast during fermentation. The highest content of the given extract was noted in experiment B-1 (19.9 g/dm3), which had the most complete taste, and the lowest in B-4 (18.6 g/dm3), it had a light and harmonious taste. In all studied wines, the accumulation of aromatic substances - aldehydes was observed. Their greatest content is in the experimental wine B-4 (33.4 mg/dm3). The content of phenolic substances is 222-246 mg/dm3. Upon organoleptic assessment, the highest score (8.6) was obtained for the variants of experimental wines: B-1 (had a full moderately fresh taste with light hints of field herbs in the aroma) and B-4 (distinguished by a bright varietal aroma with light tones of wild flowers and soft, harmonious taste).