In the mood to be overcharged and underwhelmed? Here's a tip: Order wine by the glass, advises wine editor Lettie Teague.

"I don't drink wines by the glass—they're too expensive," said my friend The Collector, looking over the list at Cru restaurant in New York City. Considering that The Collector spends an average of $150 or so on wine when he dines out (when he doesn't BYOB with one of his own $600 Côte-Rôties), such a declaration might seem hard to believe. But I knew just what he meant.

To me, wine by the glass is one of the worst deals in a restaurant. Worse than a $25 roast chicken. Not only because the prices are so high (the mid-teens seems to be the average in top Manhattan restaurants) and the wines are often much less interesting than what's being sold by the bottle, but mostly because the wines have often been open for several days. At least that roast chicken is served only once; a bottle of by-the-glass wine can be recorked and served for a number of days.

Some restaurants have even institutionalized the procedure. According to Marian Jansen op de Haar, national wine director of Fleming's Prime Steakhouse & Wine Bar, Fleming's corporate policy calls for all open bottles to be sprayed with something called Private Preserve, a blend of gases meant to reduce the wine's exposure to air. In fact, she says, they can be resprayed and recorked for up to six days (a particularly time-consuming endeavor, as every one of the 31 Fleming's restaurants sells 100 wines by the glass).

Six days sounded like an awfully long time to me; I rarely keep open bottles more than a day or so. "Our system would actually allow us to keep a bottle open for up to two weeks," Jansen op de Haar continued cheerfully. "Do customers whose glass of wine is poured from a bottle that's been open for a while get some sort of a discount?" I asked hopefully. Jansen op de Haar gave me a look that indicated my ignorance of the corporate world and simply said "No."

I thought my idea was perfectly reasonable; after all, my local supermarket has a table dedicated to day-old baked goods, discounted by 50 percent or more. Why can't restaurants do the same with their leftover by-the-glass wines? After all, if the standard rule of thumb for restaurants is that the price of a glass equals the wholesale cost of the bottle, then every subsequent glass is pure profit.

I mentioned my discount idea to Cru's wine director, Robert Bohr, when he stopped by to greet The Collector and me. (The Collector seemed to shrink from Bohr's gaze, as if embarrassed to be seen reading the by-the-glass page.) Had Bohr ever considered discounting his wines by the glass according to how long the bottle was open? Perhaps half price the second day and one-third the third? In fact, Bohr replied, Roy Welland, Cru's owner, had proposed much the same approach. "He's an options trader, so he thinks of things like that," Bohr said, then added, "I told him it would be a logistical nightmare." Too bad, as some of Cru's selections, like the $150 glass of 1982 Pichon Lalande, were wines I wanted to try but could only afford by day four. However, Bohr noted, "We usually go through all the wines—including the Pichon—within two or three days."

The two-to-three-day window seems to be standard at most restaurants. At Artisanal, a cheese-focused restaurant in Manhattan that sells 160 wines by the glass, including nine Swiss wines, floor manager Genevra Altomara told me no open bottles last more than three days. "Even the Swiss wines?" I replied incredulously, trying to imagine the diners who'd choose a Swiss wine over 151 alternatives. It was true, she said, adding, "People like to drink Swiss wine with fondue."

Although, to some, two or three days might not seem like a long time for a bottle to be open (a friend of mine keeps open bottles in her refrigerator for months—needless to say I BYOB to her house), it's not a policy I want to subsidize. Especially since it doesn't seem right in restaurants emphasizing freshness, listing menu items like line-caught trout and day boat cod. Why should day-old Chardonnay be acceptable if day-old cod is not?

Others might counter that certain wines can improve with exposure to air. Yet how many by-the-glass lists emphasize the formidably tannic wines of Cahors? Or old-vine Petite Sirah? Or, for that matter, Madeira? The fact is, most by-the-glass wines aren't the kind that benefit from extensive aeration. Sommelier favorites like Riesling, Grüner Veltliner and Pinot Noir are prized for their nuance and delicacy; theirs is an ephemeral beauty that can easily fade by day three.

Of course, these same sommeliers will invariably say they can "preserve" their wines—never mind that the verb seems more appropriate to buildings than bottles. (Wouldn't you rather look at a "well-preserved facade" than drink a "well-preserved Chardonnay"?) And the preservation methods themselves don't exactly add to the appeal: Some are designed to simply pump air out of the bottle (i.e., Vacu Vin), but most rely on gas sprayed from a can. In the case of Pek Supremo, it's argon; the popular Private Preserve brand promises to protect the open bottle of wine by "laying down a blanket of protective gas."

But how many people want to drink a Sauvignon Blanc that's been "sprayed" by a bartender at 2 a.m.? Or, for that matter, by a wine editor at noon? That was the time I conducted my own experiment with Private Preserve. I opened two wines, a brawny Petite Sirah and a delicate Russian River Pinot Noir, and though I gassed each dutifully, as per the directions (one long burst, four short), by the second day they didn't taste so good, and by day five they were pretty well gone.

Mine was much the caliber of experiment Dawn Dooley, a marketing manager at Beringer, encountered when she and her team sought a definitive study of wine preservation. "There was a lot of anecdotal evidence and amateur experimentation, but no data that conclusively proved one system was better than another," she said. So Beringer commissioned its own study at the University of California, Davis. "UC Davis students will look at the effects of each method," said Dooley. "We'll have preliminary results sometime in the spring."

Whatever the study reveals, I realize restaurateurs will continue to serve wines by the glass, although I hope the trend of restaurants offering hundreds of choices will one day end. Why do diners need 100 options anyway? Why can't they choose from a well-edited list of 10 or 20? After all, a great restaurant like New York's Daniel doesn't offer a Greek diner-style menu. Nor does it offer more than about a dozen wines by the glass.

As much as I'm opposed to wines by the glass, I do appreciate places, like Rubicon in San Francisco and Gramercy Tavern in New York City, that feature a small number of carefully chosen selections, fairly priced (a 1989 Vouvray from Prince Poniatowski is only $10 a glass at Gramercy). Lists of this size suggest someone is paying close attention to the wines, and probably not keeping bottles around for five or six days.

In the meantime, I have to admit that The Collector, my husband and I did have some good wines by the glass at Cru, including a pretty 2000 Mugnier Chambolle-Musigny ($16 a glass). However, halfway through dinner, The Collector, looking at all the glasses, each containing a different wine, remarked that they made him feel "promiscuous." My husband, sensitive to The Collector's mood, sprang into action, quickly ordering a bottle of 1996 Bachelet Gevrey-Chambertin Vieilles Vignes (which, incidentally, didn't cost a lot more than our six glasses put together). It was lovely—ripe fruit, fine tannins—"easily the best of the evening," The Collector declared. I agreed, though I wondered, was it the wine, or was it the bottle?