One of the wines Quinta do Noval produces that was never exploited by previous importers are their Colheitas, which are essentially single vintage Tawny ports that are kept in barrel until the winery is ready to sell them. These impressive wines are one-hundred percent from the vintage shown on the bottle. Considering their ages, they are reasonably priced. The 1964 Colheita possessed a ruby/amber color, excellent richness, but perhaps not quite the fragrance, complexity, or richness of the 1971. Nevertheless, it is a top-notch example of a single vintage, mature tawny ports. I do not know what Quinta do Noval's opinion might be, but it seems to me that these single vintage old tawnys, once bottled, are unlikely to change since the wine's evolution has taken place in barrel prior to bottling. I would think vintages such as these could easily last 15, 20, or even 30 years, but I am not sure since this type of port has rarely been exploited in the international marketplace. Importer: William Grant & Sons, Edison, NJ; tel. (908) 225-9000