Certified Sommelier Practice Exam

What is the process called when yeasts undergo a gradual breakdown?

1. Fermentation

2. Oxidation

3. Autolysis

4. Macération

The correct answer is: Autolysis

The process known as autolysis occurs when yeast cells break down gradually after fermentation is complete. This breakdown is crucial in the production of certain wines, especially sparkling wines, where it contributes to the development of complex flavors and a creamy texture. During autolysis, enzymes produced by the yeast break down the cell walls, releasing compounds such as amino acids, polysaccharides, and other flavor-enhancing molecules into the surrounding wine. This is responsible for the toasty, nutty, and sometimes brioche-like characteristics associated with wines that have undergone extended aging on their lees, such as Champagne. This process should not be confused with fermentation, which is the initial conversion of sugars into alcohol and carbon dioxide by yeast; oxidation, which refers to the exposure of wine to oxygen, resulting in flavor changes; or macération, which involves soaking grape skins with their juice to extract color, tannins, and other components. Understanding autolysis and its impact on wine quality is essential for aspiring sommeliers as it plays a key role in flavor development and overall wine complexity.