Tuscany: If it's Wednesday, then it must be Montepulciano ...

On a hot summer morning William F Farnham stepped out of a minibus and took his first look at a vineyard producing Chianti Rufina. It had been a long journey across the Atlantic via Frankfurt and Florence airports, but finally he was here, an American winemaker on Tuscan soil, breathing in the green, forested Appenine hillsides.

Opposite our group, the houses of a small village were clustered round a medieval tower. The villa we were visiting had that necessary, slightly rundown look that declares that it has no need to impress.

"It looks just as I hoped," Bill told me over the din of cicadas. The Farnhams run Constellation, a company that's been producing and marketing wine in upstate New York since 1945. They had seized the opportunity to join this new Grand Italian Wine Tour to the spiritual home of European wine.

"We drink Rufina at home when we can," explained Bill's wife Jo, her eyes bright. "But now we're here."

Also getting out of the minibus were Adrian, a Manchester barrister travelling with his wife Miranda, and David and Felicity, retired cheese manufacturers from the West Country. Our tour guide, Silvia, was a wine expert from Turin who'd be leading this group of serious oenophiles from Chianti to the Amalfi Coast. Wine tourism is big business in Italy but most trips stay in one region. The Grand Wine Tour is a new idea, a crash course in drinking yourself all the way from Tuscany to Naples.

It was already far too hot. "Global warming," said Federico Giuntini Massetti as he introduced himself to us. Slow and steady, Federico is responsible for Selvapiana wines up on this hilltop, east of Florence. His fattoria (farm) produces 220,000 bottles a year. I've seen them costing anything from £12-£35 in the UK.

"Heat creates more sugar," Federico explained. "And that increases the alcohol content. Our wines used to be 12.5 per cent alcohol. Now 14.5 per cent."

Given the temperature, our tour of the vines was kept thankfully short. Federico soon led everyone inside the villa that the Giuntini family purchased in 1827 from the bishops of Florence. An old man, very much the figure of a Tuscan padrone, waved his hat at me from where he was sheltering under an olive tree. "That is Francesco," said Federico. "My adopted father. He is the fifth generation of the Giuntini family making wine here."

Inside the villa we had a quick tour of the cellar, a pleasantly cool place full of French oak botti (barrels), dusty bottles and that familiar cold, stale vinegar smell that permeates all wineries. Bill wandered around in a daze of delight – but David and Adrian had plenty of questions for Federico. Had any of these wines been hidden during the war?

"No, here in Italy we did not take winemaking seriously in those days. Not like the French," Federico explained. "I think we probably hid the cheese and meat instead!"

Upstairs the tasting room was set out with chairs around a white table cloth beneath a fresco by Ghirlandaio that Don Francesco had rescued from a dilapidated chapel on the Selvapiana estate. Federico's Rufinas are strong and subtle. No wonder they're not cheap. He'd agreed in advance to let us sample five wines but sensing the men's enthusiasm and expertise Federico also uncorked his 2007 Riserva (which Silvia considered a fantastic year) and the 1980, "an excellent year" by all accounts. Appreciative noises were made. The wines were accompanied by a rustic lunch of crostini, bruschetta and guinea fowl lasagne prepared by Federico's sister.

"You have a terrible job, Silvia," David teased our guide as yet more bottles reached the table. Conversation was loosening up. Adrian asked about the economy. "This is a fantastic country," Federico insisted. "I am very proud of being Italian but it's very tough now." Looking to the future he was hoping to send his son to one of the leading wine universities, such as Bordeaux or Davis in California. "It used to be that the father and grandfather taught the next generation how to make wine but now our sons teach us."

Somewhat the worse for wear, but well pleased with our first visit, the group tripped back down to the minibus and the minibus returned us to Florence by early afternoon.

"That place was so tidy," Bill confided to anyone listening. "Our winery is a disaster. Hosepipes everywhere!"

"We normally only drink at weekends," Adrian told me almost apologetically. The afternoon was to be spent sleeping lunch off in our hotel overlooking the Arno.

The next morning everyone was up early for the first of two chianti classico tastings, the first up in the hills at a cantina called Isole e Olena. Its modern premises produce 200,000 bottles under the direction of Paolo de Marchi, an amiable Piedmontese interloper. Paolo is well known in Tuscany, not just for his rigorous production methods but also for his energy, which bowls you over. Imagine an Italian Robin Williams spouting philosophy and viticulture in equal measure.

"This is a wine that talks of a place!" he exclaimed as our group assembled in front of a stunning picture window overlooking forested hillsides. "The fingerprint of wine is in the soil." As Paolo poured from a bottle of his beloved Cepparello, David pointed out that we were having our first drink of the day at 10am. "I can't get over how decadent this feels," admitted Adrian.

Paolo had much professional advice to impart, leaving Bill with a smile of happy fascination on his face.

"Never try to improve a bad wine by blending. You just get more bad wine!" Handing out more glasses Paolo added "And never try to sell a wine you yourself don't like. I have learnt these things the hard way. And remember in viticulture no solutions come overnight!"

Unfortunately Paolo had double-booked himself this morning, so after an hour of quickfire anecdote and insight he went rapidly round the room shaking hands and leaving his wife, Marta, in charge of some gloriously sweet vin santo. His parting shot was to remind everyone that no one actually makes vin santo. "You just put it in a caratello (small barrel) and forget about it for seven years!"

The room was suddenly quiet. I asked Marta about her husband's high energy levels and she admitted that on the rare occasions he relaxes, Paolo does feel very, very tired. Out of necessity, Marta takes life more gently. She escorted the group slowly round the extensive cellars, blasted recently out of the hillside and resembling Blofeld's underground lair.

Wines at Isole e Olena proved to be no cheaper than at Selvapiana. In fact the vin santo cost €40 (£31). Despite expressions of delight, I noticed nobody bought anything – but with nine top winemakers to visit, and baggage allowance to take into consideration, it was still early days.

Leaving Isole e Olena our minibus plunged down out of the forests west of Siena to the yellow wheat fields that surround the city. At Fattoria di Felsina, lunch was laid on for us and we were joined by a group of 15 top sommeliers and restaurateurs who had arrived from England that morning. Miranda asked me which of the young men with shaven heads or spiky hair I thought had two Michelin stars under their belt.

We were then taken on a tour by Caterina, third generation of the Mazzocolin family at Felsina. We saw the cellars which open out from an ornate 17th-century barn where chianti classico is stored in huge elongated barriques, specially built in Slavonian oak to fit between the barn's marble columns. Felsina, a baroque hostelry for pilgrims en route to Rome, sits right on the southern border of Chianti Classico. It has also started producing a chardonnay, I Sistri, which is quaffable but will never be great because, as Silvia explained, grapes in Tuscany ripen so quickly.

The meal turned out to be a lengthy affair. Caterina's father, Giuseppe Mazzocolin, has raised this fattoria to near iconic status in Italy, but today he was keen to promote Felsina's four kinds of olive oil. A single bottle should cost up to €50 (£39), he explained, but until now Tuscan wine has been subsidising the oil. "If you buy olive oil for a few euros at the airport that is not olive oil," he insisted. Giuseppe grew increasingly generous towards the sommeliers, sending for older and older vintages for Caterina to uncork. You soon couldn't move on the table for glasses. Adrian was delighted when a 1983 chianti classico was sent round.

"Opening a 1983," murmured Silvia. "That's the first vintage they ever made. It's a real treat."

An afternoon break in Siena had been arranged but the day was already getting late. As dessert had failed to materialise at Felsina, Silvia tempted us away with the promise of an ice cream in the Campo. It was a good day to visit, as the track for the Palio horserace had been laid that morning and restaurants were just putting out their tables again on the clotted yellow sand. Plunged in among non-oenophile tourists again, I was suddenly aware that our wine tour was giving us unusual levels of access to an Italy most visitors don't normally see. Next up was Umbria for some Montepulciano, and beyond that Rome beckoned. Naples was 400km to the south. "If it's Wednesday, it must be Montepulciano," I wrote. Not your usual tasting notes.

Travel essentials

Tasting there

Arblaster & Clarke (01730 263111; winetours.co.uk) offers autumn wine tours of Tuscany from £1,499 per person, and Sicily from £2,399 per person, including B&B and some meals with wines, all visits and tastings, coach transfer and wine guide, but excluding flights. This year’s 10-day Grand Italian Wine Tour cost £3,450 per person. Details of the 2013 tours will be available next month.

Getting there

Adrian Mourby travelled to Florence with Railbookers (020-3327 0869; railbookers.com) which offers outbound rail travel, three nights in Florence and return flights via British Airways from £599 per person.