Browning of wine is due to the oxidation of the polyphenolic compounds present in the wine. It is associated with aging in a wine. Browning can be perceived either as a positive aspect, in the case of sherries or sweet fortified wines such as white Ports or Rivesaltes, or as a negative aspect for dry white wines. In organoleptic terms, this phenomenon translates into a loss of aromatic freshness and, in the final stages, in the appearance of precipitates of condensed phenolic material in the bottled wine.