People who drink wine from magnums are just plain happier than the rest of us. Wine Editor Lettie Teague joins their ranks at a very special dinner.

Wine drinkers are forever dividing themselves into factions: those who like red versus those who prefer white; Bordeaux fans against Burgundy boosters; Chardonnay lovers against...everyone else. But the set of drinkers that I'd most like to join are the people who drink their wine by the magnum. It's neither the size of the magnum (equal to two regular-size bottles of wine) nor the magnum's superior aging capacity (wines mature more slowly within its confines) but the fact that magnum drinkers always seem to have the best time.

My friend Park B. Smith is a perfect case in point. (In fact he's the magnum lover I'd most like to be.) Park owns what may be the nation's best private cellar, of which an incredible two-thirds (40,000 bottles) is magnums. Park is also a charming and much-sought-after guest.

I know this because it took my husband and me nearly six months to get him to our house—though our less fabulous cellar may have factored into the delay. When Park arrived, magnum in hand, he let slip that Bob Parker had warned him to bring his own wine. (Wine critic Robert M. Parker, Jr., appraised our cellar a year ago, and the shock of that apparently still hadn't worn off.)

But Park would have brought a bottle anyway, since he's also famous for sharing his wine—another characteristic, I've found, common to magnum lovers. In fact, Park not only brought a magnum of a great Châteauneuf- du-Pape (1998 Domaine de la Janasse Vieilles Vignes) but also sent along six more the next week to say thank you. Magnum drinkers don't make do with just a note.

I reported this to my friend The Collector, who replied, "I've got some great magnums too." (Wine, for The Collector, is a competitive sport.) What if he were to bring one to New York's Montrachet restaurant on their BYOB night? I countered. I'd buy the dinner if he'd bring the wine. The Collector seemed to consider this fair and said he'd call soon with the name of the wine.

The next day he phoned to announce his selection, the 1970 Château Trotanoy. I was excited: Parker had called this Bordeaux "one of the three greatest of the vintage" and awarded it 96+ points (out of 100). "Of course, I could bring the '82 Trotanoy instead," mused The Collector. "I have that in a magnum too." (The Collector could be perverse; if I show too much interest in a particular bottle, he's likely to show up with a different wine.) "Either would be great," I replied, affecting indifference—though I knew the '70 was the superior wine.

A few days later, The Collector called back. "Turns out I have the '70 Trot in a bottle as well as a magnum. Maybe we should taste both." It was hardly a proposition I'd refuse; it would be interesting to see how differently they had developed.

The reason wine ages more slowly in a magnum is that the ratio of wine to air is significantly greater. Exposure to air is what ages a wine. Indeed, wine not only ages more slowly in magnum, but many believe more evenly, too. This may be why magnums command much higher prices than the equivalent amount of wine in regular-size bottles. According to Richard Brierley, head of North American wine sales for Christie's, a case of 12 bottles of 1982 Pétrus sold at auction this year for $18,800, while a case of six magnums of the same vintage sold last year for $51,750—almost three times as much. And yet, said Brierley, the typical magnum buyer "isn't an investor but someone who just enjoys wine."

A few days before our dinner at Montrachet, The Collector called back. "I think we should invite somebody else. We can't possibly drink this much wine," he said, as if bringing so much had been my idea. "Then we can share it with everyone in the restaurant," I replied, flush with magnum-induced magnanimity. Nevertheless, I decided to invite our friend Fred Shaw, a wine merchant. Fred declared he too would bring both a bottle and a magnum. He, however, chose a 100-point wine, the 1982 Mouton Rothschild. (Fred can be competitive too.)

The Collector and Fred already had wine in their glasses when I arrived at the restaurant. "We're trying out a few things before we get started with the magnums," The Collector said casually, as if they weren't drinking but auditioning the wines—three Drouhin Burgundies from the '40s that Fred had bought from a collector in Belgium. Although they weren't magnums (rare in Burgundy back then), Fred wanted to see how they had aged. Two had held up remarkably well: The '45 Beaune Clos des Mouches Blanc was honeyed and rich, and the '45 Chambertin was vibrant. (The '49 Chambertin was corked.) Still, I couldn't help wondering how much better they might have been had Burgundians believed in magnums.

Meanwhile, Montrachet sommeliers Bernie Sun and Bruce Yung decanted the Trotanoys and Moutons at a table in the back of the restaurant. We'd asked them to pour the wines directly into glasses so we would have to guess which came from a bottle and which from a magnum. "This should be easy," The Collector predicted.

That was only half true. The Trotanoy was easy enough—the three of us guessed right almost immediately. The wine from the magnum was much less developed, in the mouth and aromatically. And while both wines showed the same lush, layered fruit, the bottle of Trotanoy was clearly at its voluptuous peak, while the magnum had years to go. The Collector observed with mixed pride and regret: "That was the last bottle I had."

The Mouton was a more challenging prospect. Both of the wines in our glasses were tight and closed, their textures similarly dense and unyielding. Once again, we voted unanimously. This time, however, we were all wrong. Bernie blamed it on Mouton's middle age, saying "The Mouton isn't expressive right now." This, he added, was common with slow-maturing wines—which tended to show better "much younger or older." We might have pondered the middle-aged betrayal of Mouton a bit longer, but the women at the next table were admiring our wine. "That's a great bottle," one said to Fred—who poured them two glasses and basked in the glow that even a closed-down Mouton in magnum could bestow.

My magnum-loving friends had certainly shared some great bottles; in the weeks that followed, I decided to open a few of my own. Not that my cellar held magnums of similar quality, though some of them may have been almost as old—not necessarily a good thing with a cellar full of Zinfandel and nonvintage Champagne.

In fact, the first magnum I opened was a seven-year-old St. Francis Zinfandel. Since Zin is best in its youth, I didn't expect much from a middle-aged bottle. So I took it along to dinner with friends at a local Chinese place, figuring its flaws might be hidden by MSG. The wine, however, was fresh and delicious, its age cut in half by the magnum. Moreover, my friends had fallen in love with the oversize bottle. One even took photographs of it, while another declared (accurately enough), "You've never brought us wine like this before!"

Emboldened, I began opening more and more magnums—some experimentally (an old nonvintage Champagne, a 13-year-old Cab that had spent half its life in a Manhattan apartment), others more expectantly (a Châteauneuf-du-Pape from Park), but always to the same hugely enthusiastic response. In fact, even though my regular-size bottles of wine are generally better than my magnums, they don't seem to make people happy in that sort of way. It must be something Park already knew. And (finally) I had figured it out too.