FRANCE - Revue des Œnologues n°173 - Permeability and sulphite levels

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Extract : 

Rosé wines are appreciated for their youthful characteristics, their fresh aromas and their bright colour. However, over the months of ageing in the bottle, under the effect of oxygen and temperature, their aromas fade and the colour browns. There is measurable oxygen uptake during bottling, and that oxygen is consumed during the two to three months after bottling. This leads to a drop in the free sulphites content, increased binding with colour compounds and a decrease in aroma compounds of fermentation origin. In contrast, the oxygen introduced through the closure progressively diffuses into the wine in very small amounts. It cannot be measured but also leads to changes in wine composition. The low permeability of some closures now makes it possible to decrease the sulphite level needed to protect the wine, while still ensuring rosé wine quality. The point is to selectthe appropriate permeability to preserve wine potential without inducing reduction phenomena, which can negatively affect aroma expression. These studies were conducted on several types of rosé wines and can be used to identify typical cases in order to guide winemakers’ choices.