Sensory characteristics changes of red Grenache wines submitted to different oxygen exposures pre and post bottling.

It is widely accepted that oxygen contributes to wine development by impacting its colour, aromatic bouquet, and mouth-feel properties. The wine industry can now also take advantage of engineered solutions to deliver known amounts of oxygen into bottles through the closures. This study was aimed at monitoring the influence of oxygen pick-up, before (micro-oxygenation, Mox) and after (nano-oxygenation) bottling, on wine sensory evolution. Red Grenache wines were prepared either by flash release (FR) or traditional soaking (Trad) and with or without Mox during elevage (FR+noMox, FR+Mox, Trad+noMox, Trad+Mox). The rate of nano oxygenation was controlled by combining consistent oxygen transfer rate (OTR) closures and different oxygen controlled storage conditions. Wine sensory characteristics were analyzed by sensory profile, at bottling (T0) and after 5 and 10 months of ageing, by a panel of trained judges. Effects of winemaking techniques and OTR were analyzed by multivariate analysis (principal component analysis and agglomerative hierarchical clustering) and analysis of variance. Results showed that, at bottling, Trad wines were perceived more animal and FR wines more bitter and astringent. Mox wines showed more orange shade. At 5 and 10 months, visual and olfactory differences were observed according to the OTR levels: modalities with higher oxygen ingress were darker and fruitier but also perceived significantly less animal than modalities with lower oxygen. Along the 10 months of ageing, the influence of OTR became more important as shown by increased significance levels of the observed differences. As the mouth-feel properties of the wines were mainly dictated by winemaking techniques, OTR had only little impact on "in mouth" attributes.