HOW OXYGEN AND AUTOLYSIS MAKE RICHER, CREAMIER SPARKLING WINES Oxygen: During the winemaking process, the wines are often fermented in oak barrels which adds subtle oak flavoring but more importantly, the oak allows more oxygen into the winemaking. This is where the term “oxidative” comes from and it adds subtle nuttiness to the wine. Autolysis: The autolytic side of this process happens while the wines sit in a bottle after their second fermentation. The yeast responsible for the second fermentation die and dissolve (autolysis) and sit in the bottle. The longer the wines touch these yeast particles, called “lees”, the more creamy the wines become. Some sparkling wines, such as Krug Champagne or Cava Gramona (a Gran Reserva Cava) will age 6-7 years on the lees to develop a rich creamy and nutty texture.