Oxidación de los vinos tintos: influencia del pH.

Grapes cultivated in warm zones have high sugar content and low acidity. The wines made with such grapes are more prone to fast evolution during maturation. Oxidation rate is pH-dependant. The purpose of this study was to compare oxidation risk in three different Malbec wines (pH levels 3.34; 4.14 y 4.33). Wines were made at the Experimental Winery, Enology I and II Chairs, of Agricultural Faculty, grapes were cultivated in the East (wine pH 4.14), North (wine pH 4.33) and South (wine pH 3.34) of Mendoza, Argentina. Assays were made in triplicate. The oxidation risk was determined by Singleton and Kramling test. Absorbance at 420 nm, absorbance at 520 nm and color density were measured. Statistical analysis was performed using ANOVA, Tukey test at the 95% confidence level. Higher pH wine registered a bigger color density increase than lower pH wines. High color density increase is related to high oxidation risk. Red wine oxidation risk can be evaluated by the modified Singleton and Kramling test. Absorbance at 520 nm must be registered and color density must be calculated. The test period might be shortened up to four days. [ABSTRACT FROM AUTHOR]