What is the primary characteristic of Gran Reserva wines in terms of flavor?

Gran Reserva wines are known for their extended aging both in oak barrels and in the bottle before release. This prolonged maturation process allows for the development of complex flavors that go beyond the primary fruit characteristics typically found in younger wines. As a result, Gran Reserva wines prominently exhibit secondary characteristics, such as those derived from oak aging—like spice, vanilla, and chocolate—as well as tertiary characteristics that emerge from bottle aging, including leather, tobacco, and earthiness.

These layers of flavor complexity are what define Gran Reserva wines, setting them apart from other categories that might focus more on fresh fruit flavors or vibrant acidity. Thus, the primary characteristic of Gran Reserva wines is the prominence of these developed secondary and tertiary flavors, which reflect the wine's extensive aging process.