Principal Grape Varieties
Tinta Roriz is without a doubt Iberia’s premium winegrape. Officially recognised in Portugal at the beginning of the 19th Century, it is also one of the oldest. It is currently grown widely across the rest of the country (where it usually goes by the name of Aragonês) and in Spain (especially in the Rioja, where it is known as Tempranillo). It is the only Iberian variety to be planted in any quantity overseas.
In the field it is easily recognised by the leaves. They have very deep, overlapping sinuses which give a delicate, snowflake-like appearance, and the young leaves stand out on account of their pale, yellowish colour. The berries are succulent and have a thick skin which protects them against sunburn and some fungal diseases. It remains, however, very sensitive to powdery mildew. For these reasons, and to encourage the development of the ripe flavours for which it is famed, it grows best on dry, well-exposed slopes.
Tinta Roriz is a potentially high-yielding variety although production tends to be erratic, largely on account of occasional poor fruit set. Clonal selection is being investigated in order to address the issue. There is a marked decrease in the quality of the fruit at very high production levels, so care needs to be taken in situations with rootstocks such as 99 R and 110 R which have induced high yields in experiments.
The fruit gives medium to high sugar production although acidity can be on the low side. Unless the berries are picked fully ripe, the wine lacks its usually impressive colour, and the characteristically powerful tannins seem more aggressive, giving stemmy, woody and herbaceous qualities to the wine. In such cases the flavour is reminiscent of red fruits such as cherry, redcurrant and raspberry.
Tinta Roriz really reaches its full potential at a high degree of maturity, delivering deep, intense wines with an aromatic profile consisting of mulberry, blackberry, black cherry and jam. The nose is often aromatic, reminiscent of rockrose and spices. The thick tannins which stabilise the colour and impart a fine astringency mean that wines made from Roriz withstand long ageing in wood or bottle without losing their structure. Since they also protect against oxidation, the wines retain a reddish hue even when quite old.
Touriga Nacional is widely considered to be the finest of the Port grapes, with references to its culture in the Douro dating back to the 17th Century. It is characterised by extremely low production which, although partially responsible for its excellent wines, reduced its popularity to such an extent that it was on the brink of extinction by the mid-20th Century. Since then, fortunately, extensive clonal selection which has identified better yielding stock whilst maintaining the high quality of the fruit has led to a resurgence in its popularity.
Touriga Nacional is a vigorous variety with a propensity to produce vegetation rather than fruit which makes it very prone to poor set. This can in part be offset by the use of a medium to low vigour rootstock and appropriate cultural methods. It is also quite sensitive to phomopsis, whilst remaining more resistant to downy or powdery mildews than some other varieties. Maturation can be relatively early given the habitually low crop load. The berries are small and dark blue owing to a high concentration of phenolic components in the skin which impart a deep colour on the wines.
These are usually intensely aromatic with an impressive depth of fruit and complexity. Black fruits such as cassis, mulberry and raspberry predominate and are complemented by the resinous aromas of violets and rockrose. Some musky or gamey characteristics might also be present. High tannin levels and good natural acidity mean that the wines have an excellent potential for ageing without loss of structure or balance.
Touriga Francesa, or Touriga Franca as it has been officially known since July 2000, is the most widely planted Port grape. Its popularity stems at least in part from its high and consistent yields which therefore need to be controlled carefully by the discerning producer in order to avoid undesirable reductions in quality. It grows well all over the Douro, although it really thrives in hot zones because, although the vegetative cycle is of average length, complete ripening requires lots of sunlight and good exposure.
Francesa is a variety which is very resistant to high temperatures because of its thick-skinned berries. However, the bunch is also fairly compact which can lead to fungal problems (such as mildews and botrytis) caused by slower drying of the fruit after rain. The leaves are very similar to those of Touriga Nacional which can make identification difficult from an ampelographic point of view, although as a general rule they are rougher, more rounded and have less deep sinuses than the latter.
The wine made from Touriga Francesa, whilst not as concentrated as that of Touriga Nacional, is robust and rich in colour and structure. To realise its full potential, the fruit demands to be grown in hot and dry conditions, and it is no coincidence that the great Vintages are usually declared in years that favour the ripening of Touriga Francesa. Even then, it is still able to retain a good acidity. It has particularly lifted, exotic floral aromas which add an essential complexity to Port blends, as well as intense red fruit flavours, rockrose, and sometimes blackberries. It may also display some earthy notes on occasions. It has a long finish but there is a tendency for pigments to oxidise and precipitate out over time.
Tinta Barroca has a long and distinguished pedigree, having been recognised as one of the finest grapes for Port and Douro table wine production since the end of the 18th Century. Although not traditionally grown very widely, a major resurgence in popularity since the 1980s has seen a substantial increase in the area planted.
Tinta Barroca is an excellent all-round performer, with above average vigour sustaining large yields of fruit high in both sugar and tannin. The bunches are long and loose, but made up of thin-skinned berries which make them highly susceptible to sunburn. It is more resistant to fungal diseases than one might therefore expect, but commonly infected by leafroll virus.
Whilst Tinta Barroca appears to be an early ripening variety, in fact the high sugar levels which it reaches early on are actually due to a concentration effect caused by dehydration through the thin skin of the berries. Underripe fruit makes soft, light wines lacking in colour and structure, so care must be taken to pick Barroca at its peak. It then has a fuller flavour of red fruits, cherry, raspberry and mulberry and a much firmer tannic backbone, although acidity is often low. The wines are noted for their strength, elegant aromas and long finish. Whilst the colour of Tinta Barroca wines is not especially intense, it has a low tendency for oxidation and therefore lasts well with ageing.
Tinto Cão is a very ancient variety which has been known in the Douro since the 17th Century. Although it fell from favour on account of its low yields, it is currently experiencing a resurgence in popularity in recognition of the quality of the fruit. Even so, it is still planted in only small amounts.
The vines are hardy and somewhat rustic, tolerating high temperatures and drought conditions. Vigour is very high and a relatively long vegetative cycle means that the fruit does not overripen even when grown with a southerly exposure. Even so, it is best grown in cooler areas or picked with a fairly low Baumé because the acid balance is better and the flavours more delicate. Tinto Cão is characterised by small bunches with thick skins that are very resistant to both sunburn and fungal diseases. It is relatively sensitive to cicadela.
Although the juice is prone to oxidation, it produces wines with sweet, fresh, floral and fruity characters on the palate. These elegant, aromatic flavours become peppery and spicier with riper grapes. Although the wines have less colour and structure than certain other varieties, they do improve as the vines age and produce very long-lived wines.
Although it is traditionally popular because of its regularly high yields, Tinta Amarela is actually quite hard to grow from a viticultural point of view. It has very compact bunches and the berries have thin skins which make them notoriously sensitive to bunch rots and mildews. It should be therefore be planted on dry soils to minimise the risk of fungal diseases.
This variety has a medium to long vegetative cycle and medium vigour. Culturally, it is important to ensure that the canopy is kept quite open to encourage air to circulate and help the bunches to dry after rainfall. It also allows better light penetration which assists fruit ripening, since otherwise the Baumés are not especially high.
The berries are juicy and produce scented, fragrant wines with good acid balance. Whilst they have a very pleasant aroma, the colour and tannins are not particularly strong.