What role does flor yeast play in the aging of certain Sherries?

Flor yeast is a critical component in the aging process of certain Sherries, particularly those labeled as Fino or Manzanilla. This layer of yeast forms on the surface of the wine in the barrel, creating a protective barrier that helps to prevent oxidation. By consuming the oxygen that would otherwise interact with the wine, flor yeast allows for a unique aging environment where the Sherry can develop distinct flavors and characteristics without becoming overly oxidized.

This protective role is essential in maintaining the freshness and delicate aromas typical of these styles of Sherry. The impact of flor yeast also contributes to the development of savory, nutty, and briny notes, enhancing the overall complexity of the wine. While some styles of Sherry may incorporate other aging methods that allow for oxidation, the presence of flor is specifically known for its effectiveness in preserving the wine's original qualities while enabling the development of unique sensory profiles.