Seventeenth century bibliography mentions the importance of this variety in the Douro and Dão regions. Historically, the best Port wines included Touriga Nacional, especially old tawnies and vintages.
Morphology
The Touriga Nacional grape variety is robust and large. The grapes are small, dark blue and have a slightly oval shape. The must is not very coloured and the skin has a high concentration of aromatic substances and phenols. Medium sized and not very compact bunches. The leaves are flat and pentagonal, average size, dark green in colour, and generally have five lobes of petiole sinuse in the shape of an open U.
Enological value
Wine produced from the Touriga Nacional possesses smooth, well-rounded and warm aromas that evoke memories of very mature wild red and black berries with some floral elements, predominantly violets. In good years, it produces an excellent sweet and resinous perfume similar to rock-rose. It has a balanced mouth-feel that becomes very smooth with the maturing of the wine. In particularly good aging conditions it provides an overwhelming sensation of fruit, evoking memories of blackberry jam with soft tannins and long aftertaste flavours of wild berries. Even when not at its optimum age, it nevertheless provides excellent wines with more unstable characteristics and more aggressive aromas and flavours. The tannins become thicker but nonetheless are easy and pleasant to savour.