What unique trait does the "Oloroso" style develop during its aging process?

The Oloroso style of Sherry is characterized by its rich, dark color, which develops as a result of oxidative aging. Unlike other Sherry styles, Oloroso does not undergo the process of flor maturation. Flor is a type of yeast that forms on the surface of wine, protecting it from oxygen and imparting certain flavor characteristics. In the case of Oloroso, however, the absence of flor allows the wine to be exposed to air during the aging process, leading to oxidation. This oxidation contributes to the deep amber to brown hues that are typical of Oloroso Sherry, as well as an array of complex flavors including nuts, chocolate, and spices.

This unique trait of Oloroso is essential for understanding its profile compared to other Sherry styles where flor plays a significant role, such as Fino or Manzanilla, which are generally lighter in color and more delicate in flavor due to the influence of flor and less oxidative aging.