Editing Port wine (section)

===Grapes===
{{See also|List of Port wine grapes}}

[[File:Porto.Grahams12.jpg|thumb|right|Vintage ports from 1870 and 1873]]

Over a hundred varieties of grapes (''castas'') are sanctioned for port production, although only five ([[Tinta Barroca]], [[Tinto Cão]], Tinta Roriz ([[Tempranillo]]), [[Touriga Francesa]], and [[Touriga Nacional]]) are widely cultivated and used.<ref name=Mayson>Mayson (1999), ''Port and the Douro'', p. 93</ref> [[Touriga Nacional]] is widely considered the most desirable port grape but the difficulty in growing it, and the small yields cause Touriga Francesa to be the most widely planted grape.<ref name=Mayson/> White ports are produced the same way as red ports, except that they use white grapes&nbsp;– [[Donzelinho Branco]], [[Esgana-Cão]], [[Folgasão]], [[Gouveio]], [[Malvasia Fina]], [[Rabigato]] and [[Viosinho]]. While a few shippers have experimented with ports produced from a single variety of grapes, all ports commercially available are from a blend of different grapes. Since the [[Phylloxera]] [[Great French Wine Blight|crisis]], most vines are grown on [[Grafting|grafted]] rootstock, with the notable exception of the Nacional area of [[Quinta do Noval]], which, since being planted in 1925, has produced some of the most expensive vintage ports.

Grapes grown for port are generally characterized by their small, dense fruit which produces concentrated and long-lasting flavours, suitable for long aging. While the grapes used to produce port made in Portugal are strictly regulated by the [[Instituto do Vinho do Porto]], wines from outside this region that describe themselves as port may be made from other varieties.