In the context of sparkling wine, what is the role of yeast during secondary fermentation?

In sparkling wine production, particularly in the traditional method known as "Méthode Champenoise," yeast plays a crucial role during secondary fermentation, which occurs in the bottle after the initial fermentation. During this stage, yeast consumes the sugars that have been added to the wine as part of the dosage. This fermentation process results in the production of carbon dioxide, which is trapped in the sealed bottle and creates the characteristic bubbles associated with sparkling wines.

The carbon dioxide not only contributes to the effervescence of the wine but also enhances its mouthfeel and overall sensory experience. This transformation is fundamental to the style and quality of sparkling wines, making it essential for yeast to be involved in generating the desired carbonation. Hence, the primary function of yeast during secondary fermentation is to produce carbon dioxide, which is critical for achieving the sparkling nature of the wine.