Impact of post-bottling oxygen exposure on the sensory characteristics and phenolic composition of Grenache rosé wines

The impact of moderate oxygen exposure on the post bottling evolution of two Grenache rosé wines has been investigated. Different oxygen transfer rate (OTR) conditions were ensured by using synthetic closures with controlled oxygen permeability and storage under controlled atmosphere. Phenolic composition was determined, at bottling (T0) and after 10 months of ageing (T10), by reverse-phase HPLC-DAD–MS analysis, performed directly on the wines and after phloroglucinolysis for proanthocyanidins. Colour was evaluated by UV–vis spectrophotometry and tristimulus colourimetry. Descriptive sensory analysis was carried out by a trained panel. Correlations were established between sensory analysis and colour, polyphenolic and enological measurements. At bottling, major phenolic compounds, in both rosé wines, were hydroxycinnamic acids, followed by anthocyanins and lower amounts of flavanols. After 10 months of ageing, a loss of sulphites, native anthocyanins and flavanyl-anthocyanin adducts, an accumulation of phenyl-pyranoanthocyanins, and an increase of the colour intensity were observed. All these changes were enhanced under higher OTR conditions, especially in the wine containing initially higher levels of phenolic compounds. The higher OTR wines were also perceived as more floral and fruity and less animal than those stored under lower oxygen exposure, in agreement with previous observations on red Grenache wines.