Effects of Micro-oxygenation on Shiraz Wine

The deliberate infusion of pure oxygen into wine, a process termed micro-oxygenation (MOX), has become a common industry practise over the past decade. Used at low rates with oak chip maceration, MOX has gained interest as a barrel substitute for wine maturation. In experimental trials, the combination of oak chips with MOX was investigated over three successive vintages. Total oxygen addition of 10.4, 6.3 and 10.7 mg L-1 for each respective vintage 2004, 2005 and 2006 were made. Using principal component analysis, vintage differences between the wines pertaining to flavonoid composition were identified as the principal attributes with greatest variability regardless of treatment. Oak chip maceration increased the level of non-flavonoids in the wine and was the second most variable attribute. No consistent variation in the measured physicochemical attributes could be attributed to MOX. Regression of Electronic Tongue sensor responses onto the physicochemical data using Projection to Latent Structures was conducted. Good calibration models (mean predictive error<15% and R2 >0.70) for attributes pertaining to phenolic compounds and wine colour could be constructed; poorly predicted attributes were titratable acidity, free and total sulfur dioxide and tannin concentration. Full descriptive sensorial analysis was conducted on vintage 2004 and 2005 wines, using a trained panel and sensory data decomposed using PARAFAC and ANOVA.