This aged tawny Porto is made from selected grapes from the best vineyards of the Cima Corgo and Douro Superior. In the winery, the newly developed, robotic “Port Toes” technology for treading allows the winery to maximize the quality of the fruit by mimicking the gentle action of human feet during traditional foot treading. Fermentation is halted by the addition of grape spirits before all the residual sugar has been fermented, creating a sweet, fortified wine. Each year, a portion of this ruby wine is set aside according to its aging potential to be added to Fonseca’s stocks for blending. The wine is aged in 600-liter neutral oak barrels, considerably smaller than those used for Ruby Portos. As the stocks age, the wines take on increasingly more nutty flavors and become more concentrated as the barrels lose 3% of their volume every year (the “Angels’ Share”) to evaporation. Fonseca cellars its aged tawnies upriver in the Douro rather than in Vila Nova de Gaia near the river’s mouth; the considerable difference in heat and humidity between these two areas lends Fonseca’s aged tawny Portos a very distinctive “baked” richness reminiscent of butterscotch. The 40 Year Old Tawny is a blend of wines, selected from these stocks, that have been aged for an average of 40 years.