| Popis: |
Cool climate viticulture in some years provides musts with an imbalance of acids at a level too high to be organoleptically acceptable. Fine balance among various chemical constituents, especially between the alcohol and acid content, is important for further product stability. Deacidification of wine is a useful tool for improving wine quality. Tartaric and malic acid make 70-90 % of the total grape acidity, which is one of the basic physicochemical parameters of wine. Moslavac (syn. Furmint feher, Mosler gelber, Jaune) is one of the white grape varieties with high to very high acidity. Over the last ten years the total acid concentration in Moslavac grape must from the north-western vineyards of continental Croatia has always been high, ranging between 7.1 and 9.7 g/L. Changes in acidic composition and sensory properties caused by different methods of deacidification in Moslavac wines from the 2001 and 2002 harvest seasons were investigated. Microbiological deacidification by Oenococcus oeni (MLF) resulted in a complete decomposition of malic acid, whereas there were no essential changes in the volatile acidity, the pH value, the tartaric and citric acid concentrations. Chemically deacidified wines contained lower concentrations of tartaric acid and higher pH values than the malolactic fermented (MLF) wines. Compared with MLF wines, the tartaric acid concentration was down to 2.2 g/L, whereas the increase in the pH value was up to 0.4 units. In both years of investigation the chemically deacidified wines were assessed as the best, whereas the quality of the control wines was the most inferior. Application of the appropriate deacidification method can significantly improve the quality of the high-acidity Moslavac wines. |
