Autolysis is the microbiological event that occurs during “sur lie” aging. After several months of aging, enzymatic changes occur within the yeast cells allowing the release of amino acids, esters, terpenoids and other natural compounds into the wine. As a result of autolysis, the wines undergo perceptible changes. The aromas that develop as a result are usually described as “yeasty,” “bready,” or “toasty.”
In the production of sparkling wines, this term is applied to the breakdown of yeast cells inside the sparkling wine bottle after the secondary fermentation is completed.