Touriga nacional is vigorous and robust, but it produces notoriously low yields and small grapes. This has made it unpopular with growers, and nearly led to its extinction in the mid-20th century. Since then, however, much effort has been spent on clonal selection of the variety so that newer cuttings are slightly more productive and sugar levels even higher.
Port is made from a blend of grapes - more than 80 varieties are planted in almost 100,000 acres in Portugal - but touriga nacional stands as the most famous and revered.
Portugal
As well as making port, touriga nacional is now also grown to produce extremely concentrated, dark, tannic table wines both in the Douro Valley and elsewhere in Portugal, notably Dão. In the same way that cabernet sauvignon is softened by blending with another grape, touriga can be partnered with local versions of tempranillo.
Another grape classified as one of the best port varieties is touriga franca (which, despite the name, has no proven connection with France). Favoured for its consistent yields, it is the most widely planted grape in the Douro Valley and grown in considerably bigger quantities than touriga nacional (four times the plantings), though it does produce less concentrated wines. These two tourigas work well together - a bit like cabernet sauvignon and cabernet franc.
Elsewhere
Touriga nacional is also grown in Australia and is increasingly being planted elsewhere, notably in Spain.
Victoria Moore recommends
One to drink now
TNAC 2005 Dão, Portugal
£10.50, Armit (armit.co.uk)
Touriga nacional may be known for the port it makes in the Douro, but some of its best dry reds, like this one, actually come from Dão, further south. Dark, grainy, savoury, almost aridly dry and with a granite-like demeanour, this epitomises the creature-of-the-night qualities that make touriga so thrilling.
One to lust after
Quinta do Noval LBV 2001, Portugal
£12.19, Tesco; £12.99 Oddbins
From one of my favourite port lodges, this is a very superior bottle for the money. Dense but savoury, it smells of freshly ground coffee, plums and prunes. It's also unfiltered, which gives it a little more texture.
Victoria Moore
Drink with
Port and stilton is an all-time classic combination. Good wine and cheese matches aren't as difficult as you might imagine, largely because you are combining two finished products. First consider texture - light and delicate, soft and creamy, hard and dry, heavy and intense. Balancing the weights of your wine and cheese as evenly as possible is step one. Also consider flavour - generally, the more flavour you have in your cheese, the more flavour you'll need in your wine.
Acidity is important, too. It's no great coincidence that high-acid cheeses, such as fresh goat's cheese, work beautifully with high-acid wines such as young sauvignon blanc. And finally, consider mould - it can often make dry wines seem fruitless and bitter. To this end, port and stilton are a perfect pair.
Matt Skinner
Background
Say it right Too-ree-ga nash-ee-o-narl
Makes dense, rich, inky wines
Good companions Tempranillo and touriga franca
Hotspots Douro Valley and Dão
Legends Fonseca, Quinta do Noval, Warre's, Taylor's, Dow's
Need to know The origins of port, and the British presence in the Douro Valley, go back to the late 1600s. When wine imports from France were banned, the British looked to Portugal for alternatives. The firm red wines of the Douro were bolstered up with brandy to protect them during the long sea journey north
If you like touriga nacional, try tempranillo
"Port is not for the very young, the vain and the active. It is the comfort of age and the companion of the scholar and the philosopher"
Evelyn Waugh
Closures (stoppers to you and me) keep wine in and harmful oxygen out, and corks have long been the closure of choice. They have come a long way since the 1600s, when French monk Dom Pérignon gave up on wooden stoppers wrapped in olive oil-soaked hemp, but the problem of corked wine (where the cork is contaminated, commonly with trichloroanisole, giving the wine a musty taste) has put buyers off. Modern technology has offered answers in the form of synthetic closures and screwcaps. Initially snubbed, these are growing in popularity: top wines are found with them, and 90% of NZ wines are now corkless. As well as limiting spoilage, screwcaps allow you to leave the corkscrew at home. Cork is fighting back, though - and it has eco-warriors, not to mention José Mourinho (face of the Portuguese Cork Association), on its side. Some studies have shown screwcap production to emit more carbon dioxide. Cork, meanwhile, is biodegradable, and cork forests are considered a vital lifeline for wildlife and protection against desertification. Plus some say wine ages better under cork. The choice, for now, is yours, but the WWF for one urges you not to "screw" the environment.