"This might be a stupid question," says the American guy, in the classic precursor to a stupid question, "but how do they get the flavour of the cherries into the wine? When do they add it?"
Marco Lori keeps a straight face. He's a qualified sommelier, someone who has studied wine and worked in the Italian viticulture industry for 20 years. He knows his aglianico from his albarola in the same way most people know their favourite breakfast cereals.
So it must be a little disheartening to lead a wine tour around the streets of Rome, to share his knowledge with fellow enthusiasts, and to be asked when the wine-makers add the cherry juice to attain the aroma we're now detecting in the freshly swilled glass of Montepulciano d'Abruzzo.
"Actually, there are no cherries in here," Marco explains to the tour group, noting the way chemical compounds present in certain wines give off an aroma similar to things we may have smelled before: pineapples, peaches, leather, chocolate, or even ripe red cherries.
This, of course, is the thing about wine. Even those who love to drink it don't always know a lot about it. You can enjoy a glass of red regularly while knowing very little about how it ended up in the bottle.
That's something the creators of Eating Europe's "Rome Evening Wine and Food Stroll" clearly understood when they planned this three-and-a-half-hour introduction to the Eternal City by night. Not everyone is a wine expert. They just want to drink the stuff, and maybe learn a thing or two along the way.
And so, we have. On both counts. We met earlier at Piazza Mattei, in Rome's Centro Storico, as the setting sun burned the city's ancient buildings a deep, rusty orange. We walked through nearby Palazzo Mattei, built in the 1400s. We saw salvaged Roman statues staring down from their plinths.
And then we got ready to drink.
First: a chardonnay from Lazio, the local Roman area. Pretty much all of the wines we're drinking tonight, in fact, are from Lazio, a region that's not well known outside of Italy, but which is loved with parochial ferocity by the Romans.
And it's good, too. The wine's crisp acidity offsets the oiliness of the food, another typically Roman item, carciofi alla giudia, artichokes deep-fried in olive oil.
Soon we move on, towards bustling Campo de Fiori, and into the shadows of spectacular Palazzo Farnese, built for the Farnese family in the 16th century, with gardens designed by Michelangelo. Though the palace is now home to the French embassy, the Farneses still exist, and they make wine, a bottle of which Marco produces from his bag and opens for us to drink in the street.
History. Culture. Legend. That's what this tour is about, and indeed what a journey into Italian viticulture is about. This country is the world's largest producer of wine; there are some 1200 grape varietals. You can't hope to learn about them all in a short tour. All you can do is drink a few nice examples and enjoy their stories.
Soon we've crossed the Tiber into Trastevere, where we eat trapizzino, Roman-style pizza pockets, and drink a merlot-cabernet franc blend from the north of Rome. The wine inspires Marco to explain his background. It turns out his father used to be a winemaker. He had a 4000-square-metre block in Rome's southern outskirts, from which he would toil year after year to produce, Marco says, "shit wine".
We visit an Abruzzese deli next, and drink that region's classic varietal, Montepulciano d'Abruzzo. We marvel at the red cherries on the nose. And we decide that stupid questions can be forgiven when the wine tastes so good.
Emirates flies daily from the east coast of Australia to Rome, via Dubai. Call 1300 303 777 or see emirates.com
Corso 281 is a luxury boutique hotel in the heart of Rome. See corso281.com
Eating Europe's "Rome Evening Wine & Food Stroll" runs Monday and Thursday nights, and costs €99 a person, including food and wine. See eatingeurope.com
Ben Groundwater toured with assistance from Eating Europe.