What is the minimum aging requirement for Sherry that has undergone biological aging?

The minimum aging requirement for Sherry that has undergone biological aging is indeed two years. This type of aging occurs under a protective layer of yeast known as "flor," which forms on the surface of the wine in the barrel. The presence of flor not only protects the wine from oxidation but also contributes to distinctive flavors and aromas associated with biological aging, such as yeasty, nutty, or briny notes.

The two-year requirement ensures that the wine has sufficient time to develop these complex characteristics while maintaining the freshness and vibrancy that define biologically aged Sherry. This aging process is integral to the quality and typicity of Sherry wines made under this method.

Wines that do not meet the two-year threshold would not be classified as having undergone biological aging, and thus, would not achieve the depth of flavor that comes from this unique aging process.