Cabernet Sauvignon Aging Stability Altered by Micro-Oxygenation

Abstract

Micro-oxygenation (MOx) is used to reduce vegetal aroma and improve color by converting anthocyanins to stable pigments. A Cabernet Sauvignon wine treated with different levels of sulfur dioxide and glutathione (GSH), was micro-oxygenated, then bottled with equivalent free SO₂ levels, and stored under controlled conditions for 28 months. The MOx-treated wines and particularly those with less sulfur dioxide and GSH during the MOx treatment showed, after bottle aging, much more acetaldehyde and stable polymeric pigments, and very stable color. MOx wines also had greater losses of sulfur dioxide (SO₂) during aging. Higher SO₂ during MOx or no-MOx treatments had more protein-reactive tannins after aging, suggesting implications for wine mouthfeel. Sulfur dioxide and, to a lesser amount GSH, added before MOx was associated with slowed wine oxidation reactions during aging, and reduced color stability, leading to greater color loss. These results show that MOx prior to bottling has a dramatic effect on the evolution of wine during aging; the MOx wines had more stable color, but also loose SO₂ protection more quickly, and so may need more SO₂ before bottling to ensure comparable stability during aging. These results suggest that MOx treatment removes some preservative factors in new wine, perhaps more stabilizing phenolics.