Fonseca’s three vineyards—Quinta do Panascal, Quinta de Cruzeiro and Quinta de Santo António—all form the backbone of the famous Fonseca Vintage Portos, produced only in vintages that are “declared” as being of the highest quality. Fonseca is recognized across the Douro as a leader of viticultural practices for Porto and has spearheaded development of organic and sustainable programs across the region. The fruit for Fonseca Vintage Port is foot trodden in granite lagares on the estate. Fermentation is halted by the addition of grape spirits before all the residual sugar has been fermented, creating a sweet, fortified wine. The wine is aged for two years in oak before being bottled unfiltered.