Port wine in all its varieties – ruby, white and tawny – has been drunk, as is compulsory when in Porto. Sightseeing has been done, also essential in this World Heritage-listed medieval city whose colourful, tottering buildings lined up along the riverfront, laundry strung across balconies and flapping in the breeze, appear as quaint and as pretty as dolls' houses.

For two days, that is the view the 100 or so mostly Australian AmaVida passengers have had of Porto from our mooring at the city of Gaia, on the opposite bank of the Douro.

It is a slow start to what will be a slow journey up a river that runs a lot slower than it used to, thanks to a series of dams. These were mostly built in the 1970s and '80s, the decades when port – if my parents' dinner parties were anything to go by – was the height of postprandial sophistication in Australia.

While river cruises of similar duration along, say, the Danube typically take in four countries, in seven nights on this Douro Delights APT cruise we berth at six ports, all in Portugal, and travel only 200 kilometres.

As well as a slow journey it is also, in one sense, a backwards one. The Douro Valley is the home of port and it is in Porto – or, more precisely, Gaia on the Douro's southern bank – where the fortified wine has been stored and sold for centuries.

The growing, picking and fermenting of the grapes takes place upstream in the quintas of the Douro Valley. The Upper Douro and the border with Spain is where we disembark the ship, having traced the story of port production from its end to where it starts, in the terraced, sometimes precipitous, always spectacular hills of a landscape that is a product of millennia of human hard yakka.

There is much drinking of port along the way and much learning about the history of the Douro, its people and their ancient wine-making enterprise. There are facts about it that we hear almost as often as we find ourselves with wine glass in hand: for instance, that wine has been produced in the Douro since pre-Roman times, and that it became in 1756 the first demarcated wine region in Europe.

But there is more to the Douro story than its famous alcohol. There are cathedrals, monasteries, palaces and castles; ancient towns and pretty villages; delicious local food; great legends of love and royalty; and awesome, world-class views around every bend in these rolling valley parts.

There is evidence of other important industry in the cork oak trees that you see along the sides of roads, daubed in blue paint that signifies when the cork was last harvested and when, nine years later, it can be again.

Tourism is the country's largest industry, although in the Douro Valley we are to find it has made only a skin-deep puncture on the real goings-on of valley life.

Cruising out of Gaia, the ship glides beneath the series of bridges that connect Porto and Gaia, including the double-decker metallic Dom Luiz I bridge, built in the 1880s by a student of Gustave Eiffel.

Soon, in the AmaVida lounge, guest lecturer Dr Barbara Sa is providing a potted history of the Douro and a foretaste of what lies ahead.

"You are going to find still a huge degree of authenticity," says Dr Sa. "[The people] are not going to move away from the normal life because you are arriving in town."

There is the sense, for all of port wine's success, that it has always been a hard life along the Douro.

The pre-dammed river, for one, could be a lethal tempest for the people and their boats, known as ribelos, which transported port barrels from the valley to the city. The barrels were never full, to ensure they would float if a ribelo was wrecked. Joseph James Forrester, an influential English wine merchant who became known as the "protector of the Douro", drowned and was never found when his boat was swamped in rapids in 1861.

In summer, temperatures rise to 45 degrees. In winter they plunge to 8 degrees:  "Nine months of winter, three months of hell", the locals say. The grapes are still picked by hand and walked off the terraces in big buckets carried on men's backs.

Dr Sa laments the Douro Valley's depopulation and the threat that that poses to quintas still owned by families and not big companies. She also fears locals are ignoring, to their great disadvantage, the potential of tourism.

Indeed, Portugal's well-publicised economic hardships are in play all around us.

As we slide in our luxury cocoon along the river's becalmed and thoroughly safe modern self, buildings in semi-ruin are visible on the steep green riverbanks; in towns and villages that we visit, old homes have been abandoned to fall into decrepitude, their owners unable to afford the cost of upkeep or to find someone willing to buy.

But there is much that has been preserved, too, over a very long time. Near the town of Resende is the 12th-century Santa Maria de Carquere monastery, where we stand inside a church gazing upon elaborate altars of intricately carved wood and gold leaf. Posies of fresh daisies are everywhere, bright pops of yellow in an extraordinary space. Our guide surprises us when he slides one heavy altar panel back to reveal faded frescoes from the 1500s underneath.

There are quintas, too, that are capitalising on tourism. One night, with the AmaVida docked at the tiny one-street port town of Pinhao, we travel by bus into the surrounding hills for dinner at Enoteca Quinta da Avessada.

Luis Barros, whose family has grown wine in this now World Heritage-listed area for generations, is an entertaining host full of fun and facts about wine-making in the Douro and the family enterprise, which also includes a museum which that has dummies in traditional dress in a giant vat squashing grapes beneath their dummy feet.

We dine on sausage, cod fritters and pork belly. There is wine and live music and a conga line starts. Which may or may not be your thing. Back at the boat, just before midnight, people are belting out Waltzing Matilda in the lounge.

On this amble upriver, which takes us up and over five locks, engineering marvels all, there is plenty of opportunity for downtime. The five-star suites are made for relaxing; the excellent movie selection is free, as is the Wi-Fi, and you can sit on your private balcony and watch the valley go by.

And yet, we see and do an awful lot during this cruise, something I appreciate fully only in retrospect, given at the time I'm busy revelling in the dawdling nature of it all.

At Resende, the "capital of cherries", to which our boatload travels in three coaches from the port of Caldas de Aregos, the fruit is there to be plucked by allcomers from the trees in the town streets. Our guides buy boxes of them for us to gorge on. They also buy the local cake, Cavacas de Resende, for us to try. It is made from just three ingredients: flour, sugar and many, many eggs – enough of them to give the cake its characteristic yellow colour and which, one would guess, come from local hens.

"In this area, people build their own houses," Portuguese guide Dy informs us. "They plant orange and lemon trees and vegetable gardens, and also their own vineyards; these people eat what they produce."

It sounds like some bucolic utopia from another century. We are in the thick of the "authenticity" promised by Dr Sa. At a former prison turned into a very neat ethnography and archaeology museum, we browse displays that have no English interpretation. This is a museum for the locals to learn about their own past.

"In these villages, people aren't set up for tourists – they don't speak English, there is no English translation," says APT tour director Marion, although no one in our tour group seems to care too much. Australians are a laid-back bunch, Marion, an Austrian, says.

The drive to Castelo Rodrigo, a fortified 13th-century border village perched high on a hilltop, is through a dun and green landscape of almond and olive trees, more vines and old pigeon houses, used for raising birds for their meat and excrement, and also by smugglers for hiding contraband, our guide says.

The tourist experience in this precious hamlet of narrow cobbled streets comes with much polish. There is a gift shop full of cork handicrafts, from handbags and shoes to jewellery and serving bowls. In the gourmet store across the way, a feast of local produce has been laid out for us: almonds either spicy, smoked or sugar-coated as well as cheese, figs and olives.

The view into Spain is magnificent from this place once in Spanish hands, then conquered by the Moors, then a refuge for Jews expelled from Spain in 1492. Christians, Muslims and Jews lived together in harmony in Castelo Rodrigo, we're told. Today, only 50 people live within its walls.

After having wandered through the village checking out buildings bearing testimony to 800 years of human comings and goings, we drink wine and munch on almonds and chat in the sunshine. Our time in Portugal is nearly over; tomorrow, we leave the boat and cross into Spain for three nights on land.

Our last night on the AmaVida is celebrated with a barbecue on the deck. After dinner there's a disco with tunes such as Dancing Queen, YMCA and Gangnam Style blaring into the night. This DJ knows  the Australian audience. They are dancing like there's no tomorrow – which there isn't in Portugal, any way. Tomorrow, we go to Salamanca. Then, Madrid. There is no time for dawdling now.   

FIVE MORE HIGHLIGHTS ALONG THE WAY

Mateus Palace

Home to the Count of Vila Real and regarded as one of the finest private residences in Europe, the image of this 19th-century pile features on the label of the legendary plonk Mateus Rose. Inside the palace are important collections of religious relics, books, artworks and furniture; outside are topiary gardens inspired by the Palace of Versailles.

Lamego

This ancient town of attractive old buildings and the best smoked ham in all of Portugal is also home to the Shrine of our Lady of Remedies, which is at the top of a monumental zigzag stairway of more than 600 steps (we are driven to the top and walk down). It is also known for its fragrant sparkling wine, Raposeira, and bola, a particular style of sandwich. A generous tasting of the local specialities is included in the tour. Also some excellent ceramics shopping here.

Teahouses

Still in Lamego, the art deco Scala Saloade Cha teahouse in the main drag is worth a stop especially for the atmosphere – it's clearly a popular meeting place for locals – and also for the Portuguese tarts, or pasteis de belem, which are 80c a pop. In Porto, the Majestic Cafe is a treasure house of art nouveau. Oh, and J.K. Rowling is said to have written some of a certain book here while sipping cimbalinos. 

Quinta do Seixo

Sandeman has been in the port business since 1790, and as well as its Porto cellars, in the Douro it has the Quinta do Seixo wine centre, which we tour led by guides dressed as the iconic Sandeman Don in flowing black student capes. The swish centre shows the steps of port production, finishing with a tasting of several wines. And there's those views again.

On-board spa

In a pocket-sized space on the AmaVida's lower deck is the amSpa, where therapist Claudia delivers a superb, Swedish-style full-body relaxation massage for 75 euros ($110).  Other offerings in this bonsai spa include a hot river stones massage and foot reflexology.

TRIP NOTES

MORE INFORMATION

aptouring.com.au

visitportugal.com

GETTING THERE

None of the major outbound international carriers from Australia fly direct. The writer flew Singapore Airlines to Singapore then Frankfurt, and from Frankfurt to Porto on Lufthansa.

CRUISING THERE

APT's nine-day Douro Delights cruise from Porto to Madrid starts at $5445 a person twin share, with departures from May to September. Price includes transfers, excursions, all on-board meals and some beverages.

APT has a  special offer of $500 air credit  a person (to be used towards airfares with SQ or of APT's choosing) valid until February 28.

See aptouring.com.au/trips/europe/eupdc09

The writer travelled courtesy of APT