Now is the time to pour yourself a glass of chilled Port. Yes, that's right, chilled Port.\r\n\r\nBefore you think I've lost my sanity, let me explain. This is not vintage Port, nor LBV. This is tawny Port\u2014aged tawny Port. It is a wine that is often served chilled in its native Portugal. "Chilled\u2014it's an extremely good way of tasting aged tawnies," insists Adrian Bridge, managing director of the Fladgate Partnership, owners of Taylor's, Fonseca, Delaforce and Croft. "It brings out the complexity and flavor in the wine."\r\n\r\nTen-year old, 20-year-old, 30-year-old and 40-year-old tawnies are the fastest growing category of Ports on the American market. And you can easily taste why. "Aged tawnies appeal to the U.S. palate," says Bridge. "They are sweet wines with great acidity, easy to drink, and lighter than vintage Ports."\r\nAged Tawny\r\nThe term "aged tawny" is used to refer to tawnies aged for 10, 20, 30 or 40 years in the old oak pipes, or casks, that fill the lodges of the Port producers. The most drinkable of fortified wines, they're packed with flavor, but are always soft, rich and seductive. While vintage Port is for the head, tawny Port is for the heart.\r\n\r\n"Aged tawnies have come of age for American wine drinkers," says Bartholomew Broadbent, whose San Francisco-based Broadbent Selections imports Ferreira. "[The market is] biggest for the more accessible 10- and 20-year-olds, but that's not surprising considering the small production of 30- and 40-year-olds. We just sold 10-year-old Ferreira to all the Disney World restaurants, which means aged tawny must certainly be mainstream now."\r\n\r\nTawnies, like all Ports, are made primarily from Touriga Nacional, Tinto C\u00e3o, Tinta Barroca, Tinta Roriz and Touriga Franca grapes, grown on the dramatically vertical slopes of the Douro River. They are produced, as all Ports are, by stopping fermentation with the addition of brandy. The only difference between tawny Ports and ruby Ports is in the longer aging in barrel: vintage Ports age for only two years, while tawnies may age for decades.\r\nIt's a question of characteristics, not age\r\nThe tricky thing about tawnies is that you may never know how old they really are. When applied to tawny Ports, the terms "10-year-old" and "20-year-old" are not intended to denote exact age. "It's a question of characteristics," says Bento Amaral, who heads up the technical section of the Port and Douro Wine Institute, the regulatory body for the Port trade. "They are blended wines, not just [wines that are] 10 or 20 years old. There is no strict control of the blend, but what we look for when we approve the blends is a style which is consistent."\r\n\r\nTherefore "10-year-old" is not a minimum, nor a maximum, nor an average. It's a taste, not a mathematical formula. In that respect, aged tawnies are more like nonvintage Champagne. Every aged tawny producer has a house stylederived from the blending of as many as 100 different wines, or as few as two. Bridge says that Taylor's aged tawnies tend to a fruity style, while many brands bearing Portuguese names tend to be sweeter, but more mature in taste.\r\n\r\nBut that's not to say that you can't tell the difference between tawnies that are labeled 10-year-old and those that are 40-year-old. Tawnies of different ages do have distinct characteristics. Some people prefer the younger, more fruity style of 10-year-olds, while others want less fruit and more complexity. "As the tawnies age longer in barrel, they lose the youthful fruit you find in a 10-year-old," agrees Amaral. "During the aging, there is an evaporation of alcohol and water, so that the older the tawny, the more concentrated it is, even though the barrel will have been refreshed with some younger wine along the way.\r\n\r\n"And tawnies which are aged in the hot, dry climate of the Douro Valley are more likely to have a burnt character," says Amaral. You either like that, or you prefer the more fruit-driven style of the wines aged in the cooler, moist air of Oporto right by the ocean.\r\n\r\nAt the 30- and 40-year-old level, the fruit has gone, but the intensity of flavor is greater. "You get a curry powder aroma," says Amaral. These older wines are rare sipping wines for serious contemplation. They are so much rarer than the younger wines that in times past rich Portuguese flaunted their wealth by perfuming their handkerchiefs with 40-year-old to enjoy the scent.\r\nChilling Port\r\nIs it proper to chill a tawny Port? It is a subject that arouses controversy among some Port drinkers. "There is still an old-school view that you can't chill any Port, even tawny," says Rupert Symington of the Symington Group, owners of Graham's, Warre's, Dow's, Smith Woodhouse and other Port houses.\r\n\r\n"At home in Porto, we drink 10- or 20-year-old at the end of our evening. We dine just before nine, and then sit and have a glass of tawny. I keep it in the fridge door."\r\n\r\nBridge echoes this: "I keep a bottle in the fridge. You can also put the bottle in an ice bucket for 20 minutes."\r\n\r\nAnother of the many pleasures associated with aged tawny is that the bottle, once open, doesn't deteriorate for several weeks. It's not like vintage Port, which must be enjoyed within a few days of being opened. Symington reckons that a tawny can last "up to a month," while Broadbent believes "three months are all right."\r\n\r\nFor many Port lovers, the idea of drinking chilled, aged tawny is good news. And those new to aged tawny altogether can now add another beverage to their repertoire of cocktails, iced liqueurs and other cooling pleasures.\r\n\r\nNiepoort 10-year-old Tawny Port; $40, 93 points. Once again, Niepoort comes through with a fabulous wine. It is dry and structured, with mature flavors that suggest that the wines in the blend are older than 10 years. There is a bitter chocolate character, intense bitter almonds and finishing freshness and acidity. Concentrated and intense as a whole. Imported by Martine's/ European Cellars.\r\n\r\nGraham's 10-year-old Tawny Port; $31, 92 points. An intensely dry, concentrated, powerful wine that tastes as if it has wines in the blend that are older than 10 years. It is powered with acidity and its firm structure. Yet it is definitely a 10-year-old in style, as the fresh fruit to finish confirms. Imported by Premium Port Wines.\r\n\r\nQuinta do Noval 10-year-old Tawny Port; $30; 90 points. This dry, balanced aged tawny is both fruity and showing good aging characters. Red fruits are cut with acidity and shaped by the old wood and spice flavors. It has a delicious, ripe aftertaste. Imported by Vintus LLC.\r\n\r\nFerreira Duque de Bragan\u00e7a 20-year-old Tawny Port; $70, 94 points. Ferreira's is always one of the best 20-year-olds, and this is no exception. The secret is in the velvet-like smoothness, which combines fig and caramel flavors and just a touch of burnt vanilla with the sort of acidity that makes you want another glass. Delicious. Imported by Broadbent Selections.\r\n\r\nKopke 20-year-old Tawny Port; $56, 92 points. Although part of Barros, Kopke still operates relatively independently and can draw on good stocks of aged tawnies. This wine certainly tastes all of 20 years, with its richness and dryness finely in balance, and with lemon jelly and intense ripe fruits shining through. Imported by Wineworth LLC.\r\n\r\nNiepoort 20-year-old Tawny Port; $92, 93 points. At first sip, this seems soft. But behind this smooth, glossy exterior there are delicious flavors of caramel and oranges. With good acidity and a twist of treacle, this becomes a fine, balanced wine. Imported by European Cellars.\r\n\r\nDow's 30-year-old Tawny Port; $98, 94 points. A superbly dense, concentrated wine that has almost a brooding, dark quality, so rich is the flavor. The hint of medicinal character just gives all this intensity a lift, and goes with flavors of roasted nuts and licorice. The finish has just the right acidity. Imported by Premium Port Wines.\r\n\r\nNiepoort 30-year-old Tawny Port; $174, 92 points. An impressively concentrated wine with classic burnt caramel aromas, and dense fig and bitter chocolate flavors. It is rich, delicious and tastes somewhat older than its 30-year label. Imported by Martine's/European Cellars.\r\n\r\nOffley 30-year-old Tawny Port; $108, 90 points. This is a finely balanced, rich but elegant wine, from a company owned by Sogrape, Portugal's largest wine producer. There is some good burnt caramel flavor, as well as ripe fruit, and a delicious, just lightly fresh finish. Imported by Evaton.\r\n\r\nTaylor 40-year-old Tawny Port; $154, 95 points. In this superb wine, elegance and weight are combined magisterially. It has all the right mature flavors, ripe fruit, intense marmalade and concentration. This is a wine with a great reputation, and the flavor doesn't let that reputation down. Imported by Kobrand.\r\n\r\nGraham's 40-year-old Tawny Port; $152, 94 points. An intense, mature wine, but one that has kept its ripeness and richness. The concentration is intense\u2014one glass is plenty. There are walnuts, bitter chocolate and a delicious, clean aftertaste. Imported by Premium Port Wines.\r\n\r\nQuinta do Noval 40-year-old Tawny Port; $125, 94 points. This is a sweet but deliciously mature wine that exudes the richness of its burnt orange flavors, layers of sweet toffee and clean finish. A great wine. Imported by William Grant.