Be warned: stopping for a sandwich in Porto might floor you for the rest of the afternoon, at least if you tuck into the local speciality, a Francesinha – generous amounts of steak and cured ham stuffed between slices of toast, swathed in a mass of melted cheese and then doused with a boozy tomato sauce, with chips and beer optional but recommended. On the bright side for the health conscious, there's plenty of chance to walk it off in Porto's vertiginous streets, which rise up from the banks of the Douro river in a jumble of winding paths, broad avenues and shady squares. And multiple opportunities to stop and stare: at the 20,000 blue-and-white tiles (azulejos) depicting scenes from Portuguese history in the São Bento railway station; at the iron facades that adorn countless shops and restaurants, and which will, our guide assures us, survive the city's gradual modernisation; at the city's magnificent Romanesque cathedral; at the famous and wonderfully preserved Lello bookshop, in which a diminutive cart distributes stock on a shopfloor railway. If you get lost, navigate by the tall bell tower of the Clérigos church, visible from virtually everywhere in the city; or by the surviving sections of the 14th-century Fernandine defensive walls, hewn out of the granite on and out of which Porto is built.
Chances are, though, that these and other attractions – the vast glass-and-steel Casa da Música designed by Rem Koolhaas, the Serralves Museum of Contemporary Art in its beautifully landscaped gardens – are not the first things that spring to mind when you think of Porto. They aren't for my father – a semi-retired sommelier – or me. Speculating about what to expect on the short plane ride from Stansted, we can muster only one word: port.
It's a correct but partial view that the city's tourism officials, hoteliers and restaurateurs are keen to expand by drawing attention to Porto as a breath-of-fresh-air alternative to other European city-break destinations, such as Barcelona, Berlin and Amsterdam. For the first two nights, we stay in the palatial Yeatman hotel, which sits overlooking the Douro from the Vila Nova de Gaia region on the south side of the river. Barely a year old, the hotel is the brainchild and pet project of Adrian Bridge, the managing director of Taylor's, and although port and wine are central to its aesthetic – from the decanter-shaped swimming pool to the Caudalie Vinothérapie treatments in the vast spa – he is keen to make sure Porto no longer hides its light under a bushel.
For the fairly well-heeled traveller, the Yeatman is a luxurious and comfortable base, all hushed corridors you could drive a car down and impeccable service; right next to the byzantine network of narrow roads that connect the city's long established port-wine cellars and a short hop over one of Porto's six river bridges to the bustling north side. Those who prefer to stay right in the heart of town might try the Teatro, a more modern (and modestly priced) hotel that takes its design inspiration from the theatre that stood on the site in the 19th century. Going upscale again, there's the five-star, almost implausibly beautiful Infante Sagres, where the likes of Bob Dylan and the Dalai Lama have stayed. We don't bunk in with them, but the hotel has recently opened a brasserie-style restaurant called Book, and we enjoy a delicious dinner there.
We also visit a couple of posher establishments that seem to fall in with the image of the hip new Porto currently being promoted. They are fine, but it seems to both of us that they offer the kind of food and atmosphere not hard to find in most European capitals; self-consciously refined, artfully presented, comparatively expensive. But the one culinary experience not to miss is eating barbecued sardines in the harbour district of Matosinhos, a short drive from the city centre. Follow the smoke and head for the Rua Heróis de França, where you can take your pick from a lengthy row of plainly decorated restaurants, each with an outsized pavement grill and bursting with people – all piscine life is on the menu, but the sardines, newly caught and whacked on the barbecue with nothing but salt, are sensational (and unfeasibly cheap).
Porto's enthusiasts are right to point out that there's far more to the city than its most famous product but you'd be unwise not to pay it some attention. Sit on the banks of the river and sip it in its white, pink, ruby, tawny and late-bottled vintage incarnations, looking idly at the rabelo boats that are now a tourist attraction but were traditionally used to transport casks of the stuff down river from the Douro Valley. And, if you're here for more than a couple of days, don't miss out on the chance to head further inland to the small towns and never-ending vineyards of the Douro itself, less than a couple of hours away by car and also reachable by train to Régua or Pinhão, or by river cruise. We drive and experience proper dropped jaws when we turn off the motorway and arrive at the first viewing point: from high up, all you can see is a vast expanse of broad river and enough grapes, it seems, to keep the world drunk for ever.
In 24 hours, we manage to lunch on roast kid at Régua's splendid Castas e Pratos restaurant, visit the Douro museum, relax in the cool luxury of the Aquapura spa hotel and sample the wares of no fewer than four different quintas (including the Quinta do Seixo, owned by Sandeman, where, somewhat comically, we are shown around by a man in the trademark black hat and cape). At one, the family-owned Quinta da Pacheca, my dad and I sample the delicious wines and port so comprehensively that a cooling swim and a short nap are required before dinner (after which, of course, more port). We're certainly not up to the grape-treading that you can participate in at some of the smaller quintas – although most grape-crushing is now mechanised, traditional methods are still to be found. Spittoons are not much in evidence and so a word of caution: unless you are teetotal and have nerves of steel, consider enlisting the services of a driver to take you on quinta visits: when we visit, during the September harvest, the fairly challenging roads are further complicated by the constant traffic of grape trucks.
By the end, I feel I know more about port wine than I had imagined possible: that its grapes grow so well here because of the schist soil that regulates night-time temperatures; that one of its greatest producers was a woman named Dona Antónia Adelaide Ferreira; and that the little chapels that dot the riverside sprang up to bless the rabelo boatmen who might come a cropper in its treacherous shallows. I also realise that I will come back – here and to Porto – time and again, and that its champions are right to think it can give other short-haul destinations a run for their money.