In which condition does flor yeast thrive during Sherry production?

Flor yeast, crucial for the production of certain styles of Sherry, thrives in conditions characterized by low oxygen levels. This specific environment is ideal for the yeast because it allows for the growth of a thick layer of flor on the surface of the wine, which helps it to protect the underlying wine from oxidation while also imparting unique flavors and aromas.

During the aging process, the flor serves both as a protective barrier and as a contributing agent to the development of characteristics that are distinctive to styles such as Fino and Manzanilla. The low oxygen levels are essential because excessive exposure can lead to oxidation, which is detrimental to the quality of these particular Sherry styles.

While factors like sugar concentration, humidity, and light can play roles in the overall production and aging process of Sherry, they do not create the optimal conditions for the thriving of flor yeast in the same way that low oxygen does. In fact, high sugar concentrations are more conducive to different fermentation processes and can hinder the activity of flor.