Wine bars are an idea whose time (a) has come (b) is coming or (c) has come and gone.

The answer, arrived at after a long afternoon and a longer evening of in-depth research is: all of the above. In recent months, two wine bars -- La Chaumiere and the Champagne-Beaujolais -- have closed. Four new ones -- the Carlton Wine Bar, La Sorbonne, Chez Maria and Suzanne's -- have opened. One more -- Coleman's -- is expected to open soon.

Research, which included only the live specimens of wine bars -- was conducted not only by a reporter but by a panel of people who have immersed themselves in the subject for a total of well over a hundred years.

The study began at THE CARLTON WINE BAR (Sheraton-Carlton Hotel, 16th and K Streets NW, open 4 to 9 Monday through Friday) over the protests of one member of the panel who, on a previous visit, had been asked not to light up another expensive cigar. The room, which looks like the library gentlemen used to retire to after dinner, is dark-paneled, carpeted and furnished with wing chairs, settees, coffee tables and books on wine scattered casually on the mantelpiece of the fake fireplace.

Most of the cozy groupings are for two to four people, but, after a 15-minute wait on a recent Friday evening, cellar master and maitre d' Michael Lavenson rearranged some furniture and seated our group of six.

The carte, which changes every Monday, included five white wines, one champagne, and three reds, ranging in origin from Washington State to Bordeaux and in price from $2.50 to $4.75 a glass. In addition, there was a Cabernet Sauvignon Mondavi 1977 available for $8 per half bottle. Then there was an unlisted special -- three ounces of Chateau Mouton Rothschild '78, a claret, for $9.75.

"But you'd better reserve right away because there's very little left," Lavenson warned.

Afraid of being cut out of a good thing, one of the panel ordered a glass of the claret. The rest of us ordered one glass each of five other wines, with the clear understanding that everyone could take sips of everyone else's selection. We also ordered a plate of cheese, which comes with bread, grapes and a strawberry, for $4.

The cheese was wolfed down too quickly to permit intelligent comment, but the Chateau Mouton Rothschild was quite ordinary, a clear disappointment considering the build-up and the price. A less expensive disappointment was a Chenin Blanc (Cassayri Forni, Napa, 1978) at $2.50 a glass.

"I should have brought my flask," lamented Gabrielle Hill, who had ordered the Chenin Blanc. "But I thought we were going to places where all the wine would be drinkable."

Hill habitually carries a flask of cassis -- her equivalent of a gong -- to pour discreetly into glasses of white wine she considers undrinkable. Undrinkable or not, the rest of us gulped it down and then went on to better things, especially a 1979 Sauvignon Blanc from the Stonegate vineyards in the Mount Shasta area of California, at $3.50 a glass, and a 1976 Cabernet Sauvignon from the Chateau Sainte Michele in Washington state.

When we praised this latter wine to the cellar master, he told us it was hard to get but invited us to try, on the house, a cabernet of similar quality from the San Martin vineyards in California.

"But don't go overboard or I'll charge you," he warned, leaving the bottle on the table. Of the Chenin Blanc we found undrinkable, he sympathized but did not apologize:

"I have to have at least one wine on the menu for less than $3 a glass," he explained.

On to the CHAMPAGNE-BEAUJOLAIS, which helas, had disappeared from the ground floor at One Washington Circle and been replaced by the Foggy Bottom Cafe.

"There just wasn't enough traffic," explained manager Jack Nicholson. "Besides, I've just come from New York and wine bars are dead there."

But a few blocks away, the wine bar at LA SORBONNE (2507 Pennsylvania Avenue NW, open Tuesday through Saturday 5:30 to 10:30) was doing a slow but steady business. Adjoining the restaurant, which opened about two years ago, the recently opened wine bar has a cafe-like ambiance with wood-and-tile tables and a storefront view of the avenue.

The lower overhead was reflected in the prices -- with many wines in the $2- to $3-a-glass range.

The gamut ranged from a Coteaux du Languedoc for $1.80 to a Chateau Brane-Cantenac Margaux 1974 for $4.75 a glass. Although not all of the wines on the printed sheet are normally available by the glass, Jacques, the amiable and knowledgeable cellar master, will open any bottle if there is a demand for two or more glasses. Since we were determined to try only one glass of as many wines as possible, he graciously made an exception and opened a Puligny Montrachet 1977 -- one of the great white burgundies -- for only one glass.

Fortunately for those who cannot drink wine without eating more than tidbits of cheese, La Sorbonne's wine bar has a food menu. There are salads, snails and quiche Lorraine, but we ordered the house pate, a country pate for $2.95 and a fondue Suisse for $10.75. The fondue was meant for two, but Jacques brought six forks and extra bread and we all got enough nourishment to face the throngs of Georgetown and make our way to the Chez Maria wine bar.

The CHEZ MARIA WINE BAR (3338 M Street NW, open 5:30 to 11 Tuesday through Sunday) is entered through a Vietnamese restaurant and looks like somebody's basement rec room. But despite the lack of ambiance it's a serious wine bar and a good place to drink.

Chez Maria has theme weeks, and the night of our visit the theme was "France's Best White Burgundies." Featured were four excellent burgundies: Chablis, Bouchard 1979 at $2.40 a glass; a Puligny-Montrachet, Clos du Chaniot, Roland Thevenin 1978, at $4 a glass; a Chessagne-Montrachet, Morgeot, 1978, for $4.25 a glass; and a Corton-Charlemagne, Antonin Rodet 1978, for $5.50 a glass.Unable to resist a package deal, we opted for the special, one three-ounce glass of each for $14.75. The $1.40 we saved made a down payment on a generous wedge of brie ($2), and we supplemented our beverage supply with other selections from the list, which started at a bargain-basement $1.10 a glass for an Italian Barbera d'Asti.

The French burgundies were all superb, as expected, but an unexpected delight was a domestic Gewurztraminer (Chauteau St. Jean, Sonoma, 1979) for $2 a glass. It was not at all sweet, as one expects wines with German names to be, but spicy and dry, in what the young but knowledgeable cellar master informed us was the Alsatian style.

SUZANNE'S (1735 Connecticut Avenue NW, open 11:30 to 10 weekdays, weekends until 1), the newest of the wine bars, sits atop its own carryout, from which you can take home some of the same foods served upstairs.

According to habitues of the wine pubs that are now very popular in London, Suzanne's is the closest local approximation. As at such London pubs, there is plenty to eat as well as drink, but no pressure to order a meal. The decor consists of wood, tile and a few antiques, and you can sit at tables or at the bar.

At a recent lunch, we sat at the bar and chatted with the bartender-cellar master, whose name is Deliah -- although there really is a Suzanne.

"They only make Zinfandel and it has the flavor of crushed raspberries," said Delilah, approving our selection of a Calera Zinfandel 1977 for $2.50 a glass. The wine is made in Templeton, California, which Delilah tried unsuccessfully to locate for us from a mini-library behind the bar.

Most of the by-the-glass wines, which were chalked up on a blackboard, were, like the Calera Zinfandel, high-quality domestic wines from small "boutique" vineyards. A Tualatin Pinot Noir 1976, from Oregon, for $2.50 a glass and a Dry Creek Fume Blanc 1979 for $2.35 were among the most interesting.

"It's value," said Delilah, explaining the preponderance of domestic wines. "We have a very fine Bordeaux claret on the list, but who's going to pay $6.75 a glass?"

For less than the price of a glass of the import, we got a lunch large enough for two. The Vintner's Special, consisting of two kinds of salad, cheese, bread and pate, cost $6.25 and was the most expensive food item on the menu.

Later, still savoring the hint of crushed raspberries in the Zinfandel, we looked up Templeton in a National Georgraphic atlas. It's midway between Paso Robles and San Luis Obispo.