Research Note: The Influence of Micro-oxygenation on the Long-term Ageing Ability of Pinot noir Wine

Abstract

In this study, Pinot noir wines were bottle aged for 12 and 18 months after micro-oxygenation (MOX)applied before or after malolactic fermentation (MLF) at two doses (10.8 and 52.4 mg/L/month). Afterageing, a greater decrease in the total SO2 concentration was found in wines with the higher MOX dosage,demonstrating a long-term impact of higher oxygen exposure on wines’ SO2 requirement. Meanwhile, anegative impact of MOX on wine colour development occurred over time, resulting in a large loss of colourmeasures (i.e., 420 nm for brown hues, 520 nm for red colour, SO2 resistant pigments, and colour intensity),which was greater with the early oxygen exposure. This was linked to a significantly lower content of largepolymeric pigments in MOX treatments. Tannin concentration was, in the end, not affected by the MOXtreatments. However, regarding tannin composition, considerably higher (-)-epicatechin extension unitsbut much lower (-)-epicatechin terminal units were found with MOX treatments. In addition, a significantreduction of tannin trihydroxylation (%Tri-OH) but a higher galloylation (%Galloyl) and mean degree oftannin polymerisation (mDP) remained in wines with MOX, indicating a long-term negative influence onastringency intensity.