Chromatic Characteristics and Optically Derived Compositional Descriptors of Micro-oxygenated Wines from Vitis vinifera cv. Merlot and Cabernet Sauvignon

A 6-month time series of chromatic characteristics and optically derived compositional descriptors was obtained for replicate full-scale commercial micro-oxygenated trials and control wines from two varieties, Vitis vinifera cv. Merlot and Cabernet Sauvignon. Two-week post-fermentation micro-oxygenation treatments resulted in a suite of optical properties and compositional descriptors significantly different from corresponding replicate non-micro-oxygenated control wines. After several months of barrel aging, both the Merlot and Cabernet Sauvignon micro-oxygenated wines had increased color density (35% and 7%, respectively), higher color due to derivatives resistant to sulfur dioxide bleaching (40% and 45%, respectively), and higher wine age (10% and 35%, respectively) relative to the controls. Merlot wines decreased in yellow tonality (3%) due to treatment, whereas the Cabernet Sauvignon wines increased in both yellow (3%) and blue tonality (6%). Cabernet Sauvignon wines responded to micro-oxygenation about 10 to 30 days slower than their Merlot counterparts. Principal components analysis using the optical descriptors was successful in distinguishing micro-oxygenated from control wines within and between varieties and in following the time-course of wine aging for each treatment.