Their glasses aren't empty. My friend Dan and I have probably realised this at exactly same time, as the Argentineans in our tour group scrape their chairs back and depart from the table, leaving behind rows of glasses still partially filled with white and red liquid.
"Are they going to finish those?" Dan asks incredulously, pointing at the glasses.
I shrug. "Doesn't look like it."
Once again, we've both had the same thought at the same time. Would it be a massive faux pas to reach over and drain our colleagues' wine for them? There's a silent agreement that yes, it probably would be. But we're still considering it.
This is a wine tour in Mendoza, Argentina, and it's a little different to any wine tour the two of us have done back home. For starters, there doesn't seem to be much wine drunk. We're visiting just three wineries in a full-day tour, and the local Argentinians, who make up the bulk of our tour group, aren't even polishing off all of their modestly poured tastings.
"It's as if they don't even want to get drunk," Dan says.
He's right. They don't seem to want to get drunk. They seem to want to learn about the winemaking process, take in the scenery, or the "terroir", and sample small mouthfuls of the product. But they don't want to get drunk.
This contrasts sharply with the last wine tour Dan and I went on, with some friends in Margaret River a few months beforehand. That day had started off respectably enough, with careful tastings and assessments of each drop, before its inevitable descent into drunken silliness by about the sixth winery.
A fortnight after that tour an entire carton of wine turned up on my doorstep in Sydney. My girlfriend and I looked at each other. "Did you buy that?" We both shrugged.
And yet here's Dan and I in Argentina, onto winery number two for the day, and we're seriously contemplating drinking other people's dregs.
Wine cultures vary around the world – the drinking of it as much as the style of the stuff in the bottle. Australians, or at least the ones I know, might like to "get their money's worth" on a wine tour by drinking every last drop made available to them, but in Argentina they're all about gentle appreciation.
This vineyard tour is taking us through the Valle de Uco in Mendoza, and it includes a whole lot of education, and a small amount of tasting. At each of the three wineries we're being taken through their entire winemaking process, from the growing of the grapes to the fermentation, the storage and the bottling. We're talking about the intricacies of the procedure. We're seeing it all with our own eyes.
And eventually we're going up to a little room where four or five very small glasses are placed in front of us and dashed with a little liquid. Dan and I invariably knock ours back in a couple of gulps and say something along the lines of, "I don't mind that." The Argentinians sip delicately on theirs before placing the bulk of their tasting portion back on the table and walking outside to admire the view.
It's times like these that you realise what a wildly different approach to alcohol we have in Australia to much of the rest of the world. We might share our binge-drinking antics with close relations from the Anglo-Saxon world, but most other cultures tend to take these things a little more cautiously.
In Japan there are public vending machines selling beer. Can you imagine that in Australia? There'd be a queue of 16-year-olds around the block. In Japan, however, no one abuses the system, and no one gets too drunk. At least not in public spaces.
In France kids start gurgling wine from a young age, but you don't find many binging teenagers. All of the exoticism has been taken away from alcohol already. It's not in the culture to get too boozed.
And then of course there's Argentina, where it appears that a love of wine is born more from an actual love of the taste of wine, rather than what copious amounts of the stuff can do to you.
And so Dan and I continue on our tour, marvelling at the restraint of our fellow tasters, and eyeing off their leftovers like your mates at the pub staring at the bowl of chips you just ordered. We manage to restrain ourselves, which is admirable under the circumstances.
It's a different culture, we say. And at least there won't be any unexpected cases of wine turning up at our houses in a few weeks' time.
The writer travelled as a guest of Chimu Adventures