A few words about this item from chef José Andrés:

This is the king of Sherry vinegar! To be considered a Gran Reserva ("Great Reserve") vinegar, it must be aged for at least 10 years. Sherry wine, made with grapes from the wine-growing region of Jerez, is stored in giant oak barrels, and the result is worth waiting for: a beautiful deep amber color and amazing taste - acidic with hints of roasted nuts and spices. Such a refined ingredient deserves to be served with the best foods: drizzled over tomatoes fresh from the garden or used to add a complex array of flavors to almost any dish. A truly royal treat!