When wine drinkers gather ’round the campfire to tell tales of their greatest wine triumphs, they talk about the rare and the precious. Sagas abound about ’47 Cheval-Blanc. Or you get stories about double magnums of Chateau Lafite-Rothschild bought directly from the estate. And there’s always a raconteur holding forth about Romanee-Conti.

But when my turn comes, I tell them that the rarest wine I ever drank was filtered through a sock.

Since it’s summer, and since the wine in question is the single greatest summer wine I know, it seems a good time to tell the tale again. So gather ’round the, er, air conditioner and let me tell you the true story of the rarest wine I ever drank.

Now, it’s true that in my line of work, I’ve guzzled a fair share of the world’s most precious wines. Why, only a few months ago, I was at a tasting of a dozen or so 1945 red Burgundies, including, yes, a 1945 Romanee-Conti. (It was all right, but not as great as you might imagine. Such old wines rarely live up to one’s fantasies.)

Still, the rarest wine I ever drank remains the one filtered through a sock. It was a Moscato d’Asti.

Nobody thinks about Moscato d’Asti as a rare wine, for good reason. It isn’t. Made entirely from the moscato bianco grape grown on the very steep, chalky-clay hillsides in northwest Italy’s Piedmont region, Moscato d’Asti has a delicacy, an ethereal quality, that almost no other wine can rival. Not least, it’s extraordinarily low in alcohol, with less than 6% alcohol. (A chardonnay, in comparison, typically clocks in at 14%.)

When I was living in the Piedmont region researching a book, I felt duty-bound to become expert in Moscato d’Asti. (It’s the sort of rugged challenge we wine writers take on.)

I knew, of course, about its big-name brother, the world-famous Asti Spumante, which is produced in industrial quantities by big wineries. It, too, is 100% moscato bianco, but even the best Asti Spumante gives only a hint of what the far more artisanal Moscato d’Asti can achieve.

What’s the difference? Essentially, it’s that between a workhorse and a race horse. Moscato d’Asti is the thoroughbred, thanks to the way it’s made and its vineyard lineage. It’s what the growers make for themselves. Production is small. The wine is what the Italians call frizzante, which means lightly bubbling. A grower could make such a wine in his home cellar. A fully foaming (spumante) Moscato, however, requires expensive, special vats that only big wineries can afford.

Because it was so artisanal and localized, Moscato d’Asti was only rarely commercialized. A grower made it for himself, his family and friends, and a few private customers. It was – and is – the ideal conclusion to one of Piedmont’s heroic dinners, with their six successive plates of antipasti, two pasta courses, and then a meat course. By the end of such a siege, you had no room left for anything but a refreshing glass of light moscato accompanied by the delightful cornmeal cookies called krumiri.

So there I was, trying to become expert in Moscato d’Asti. I sniffed, I tasted, I swirled – but I never spit. What the hell, it’s only 6% alcohol. I was getting a pretty good notion of who the best producers are. More about them in a moment.

I was feeling pretty good about my efforts until I mentioned them to Barolo producer Aldo Conterno. He likes Moscato, too, but he doesn’t make any himself. Aldo sees it as his life’s work to instruct me on any number of important matters, such as why “America is the greatest country in the world” (he served in the U.S. Army), among other issues.

“Moscato?” said Aldo contemptuously. “Why you’ve never tasted the real Moscato. You have to taste Signora Gemma Chionetti’s homemade Moscato. That’s the real thing. She puts it through a sock.”

When I heard that, I was quivering like a springer spaniel on the scent. I had read about how traditional Moscato was made by filtering the wine through a sock. But I never thought that even in Piedmont, a pretty hidebound place, anybody was still doing it.

You see, the way Moscato is made frizzante, or lightly bubbling, is by bottling the very young wine while it’s still fermenting. But you don’t want all the yeasts in the bottle, as it will then explode from the pressure of too much carbon dioxide. (When yeasts feed on the sugar in the grape juice, they create alcohol and carbon dioxide. Put this process in an airtight bottle or tank and, voila!, you’ve got sparkling wine.)

So the old-timers used to filter the still fermenting wine through a series of hemp tubes or socks. This would remove any dead yeast cells, as well as most of the living, still-engaged-in-fermenting ones. A rough filtration, it was performed multiple times until the wine emerged reasonably clear. Then it was bottled.

To say that this was an inexact science hardly captures the rough and ready quality of the procedure. As a result, part – sometimes all – of a year’s production would explode in the cellar. Too many live yeasts made it through the sock and continued fermenting inside the corked bottle, creating more pressure than the bottle could withstand.

A month or two later, you’d hear a shockingly loud explosion in the cellar and find a fragrant mess with glass shards everywhere. And heaven help you if you’re in the cellar when a bottle explodes. You can be seriously injured. (In the old days, cellar workers in big wineries making sparkling wines wore stiff leather chest protectors and fencing masks.)

But things weren’t always so predictable. Cellars would be so cold in the winter that yeasts went dormant. But once summer arrived, cellars warmed up and the dormant yeasts would resume feeding and multiplying inside the bottle. And then, boom! (Today, filtration is exact. You can remove every yeast cell.)

Now you know why I was so surprised – and excited – to hear that that Signora Gemma Chionetti made a Moscato the old way. (Her husband, Quinto Chionetti, is famous for his red dolcetto wine.) I pleaded with Aldo Conterno to ask Signora Chionetti to let me taste her filtered-through-a-sock Moscato. She assented.

“Oh, I make maybe 120 bottles a year for ourselves and our friends,” she said when I visited her. By the time I got there, it was summer and she was down to her last dozen bottles. “At least I think that’s how many I’ve got,” she laughed. “I haven’t been down to the cellar to see if anything has broken.”

She returned with three bottles carefully held upright so as not to disturb the heavy sediment from the dead yeasts that had made the wine bubbly in the bottle. “You don’t want to shake it too much,” she said. She was not smiling when she said that.

She pulled the cork, and the wine that emerged was glorious. It was similar to today’s best Moscato d’Asti bottlings in its freshness, vibrancy, and incisive, delineated flavors.

But there was one big difference: texture. Her Moscato was thick on the tongue, denser than any other I’d tasted before or since. It was the most dramatic demonstration of the effects of filtering – or rather, non-filtering – that I’ve experienced. The glycerine richness of that texture is absent in today’s necessarily more finely filtered renditions.

She offered me two bottles to take home that evening. “How far away do you live?” she inquired. “Not far,” I replied, “maybe 30 minutes away.” “Then it’s okay,” she said. “The bottles should make it there safely. Because once they warm up, well, you never know. Anyway, you’d better drink them fast.”

I made it home in record time and gingerly cradled the two bottles to the refrigerator as if they were gelignite. They didn’t explode in the night. Figuring that such luck wouldn’t hold forever, my wife and I greedily polished off both bottles the next day. To this day, it is the rarest wine I’ve ever drunk.

HERE ‘ S THE DEAL

Buying Moscato d’Asti is one of wine’s easier assignments. Since it’s such a specialty item, almost every producer’s version is worthwhile as only a small, high-minded group of Piedmontese producers offer Moscato d’Asti.

Prices range between $12.95 and $19.95 a bottle. Freshness is critical, as Moscato wines lose their fragrant qualities the older they get. Look for the 2004 vintage.

Although Moscato d’Asti is a sweet wine, its acidity is so high that it’s a most refreshing wine to drink. Serve it as an aperitif or as the world’s greatest sunset-sipper. Moscato d’Asti is also an ideal dessert wine, superb with fresh fruit, simple cookies, pound cake, cheesecake, and – this will surprise you – chocolate truffles. It’s astoundingly good with chocolate because of that high acidity and Moscato’s flavor, which complements those of dark chocolate.

Several are outstanding, notably Paolo Saracco, Rivetti, Perrone, Gatti, and Forteto della Luja. When you find one of these producers, you will land on Moscato d’Asti at its best. Each offers Moscato d’Asti in a slightly different style.

Paolo Saracco is my top choice. It’s our house Moscato d’Asti, as I find his version the closest of all to Signora Chionetti’s antique version. Also, Saracco is the best deal at the rock-bottom price of $12.95 a bottle. (The price is lower because Saracco changed importers and his wine is now brokered into America, resulting in a noticeably lower price than before.)

Saracco once even made some antique-style Moscato d’Asti for a tradition-minded restaurateur who transported the roughly filtered wine in a refrigerated truck. He told me that he’ll never do it again because he lost sleep worrying about the bottles exploding in the restaurant’s cellar.

Forteto della Luja is rarer and from a small zone called Loazzolo. It has exceptional textural density, if not quite the same delicacy and finesse as the best Moscato d’Asti bottlings. Not easily found, although certainly worth a search, it will cost about $19.95.

Rivetti (also known as Cascina La Spinetta) makes a very perfumed, delicate style that is extremely attractive. Designated “Bricco Quaglia,” Rivetti is superb Moscato d’Asti and varies in price from $15.95 to $19.95. It’s widely available.

Elio Perrone’s bottling, designated Sourgal, is another monument to Moscato delicacy. Like Rivetti, it has an ardent following as well as a similar asking price.

In addition to these stellar examples are yet other fine producers such as Bera, Vignaioli di Santo Stefano (Ceretto), and Vietti.