Anyone willing to forgo a bright, sunshiny afternoon last weekend in exchange for free wine would have had the rare opportunity to sample nearly 100 wines from Virginia, Maryland, Pennsylvania and New York State. Hosting the event was Morris Miller Liquors who invited 13 Eastern wineries to present samples to everyone who poked a head in the door. And with the wines came many of the winemakers, who reveled in recounting their triumphs and tragedies.

Still in the early stages of wine producing, most of these wineries are feeling their way, frequently producing an astonishing number of wines in an effort to match the climate, soil, grape and vinification technique to produce a coherent and, perhaps, spectacular wine. Ingleside Plantation Winery in Oak Grove, Va., confessed to having 30 grape varieties under cultivation. Chateau Esperanza in Bluff Point, N.Y., arrived with -- among other wines -- three distinct varietal bottlings made from the cayuga grape, a French-American hybrid developed in New York.

With 17 bonded wineries in Virginia, six in Maryland and 26 in Pennsylvania, winemaking in the mid-Atlantic states is beyond the back-yard stage. Each state has its own winegrowers' association, and information is freely exchanged, to the advantage, ultimately, of the consumer.

While Easten wine growers once resigned themselves to native American grapes like niagara and concord, today the movement is listing decidedly toward vinifera like cabernet sauvignon, chardonnay, riesling and sauvignon blanc. Sharing the storage tanks are better French-American hybrids, including seyval blanc, vidal blanc and mare'chal foch. With the development of sprays and other chemical treatments, vinifera is expanding rapidly and, generally, without major disaster.

The march towards vinifera, however, was detoured last winter when the cold weather decimated a substantial portion of chardonnay vines in Maryland and Virginia, particularly at the highly respected Byrd Vineyards in Myersville, Md. Bob Lyon, the winemaker, moaned that 80 percent of the chardonnay vines may have been lost. (This was one of the few tragedies acknowledged last weekend by a winemaker.)

Between pouring tastes of their wines, Hamilton Mowbray of Montbray Wine Cellars in Silver Run, Md., and Walter Luchsinger of Piedmont Vineyards in Middleburg, Va., reviewed the merits of wines from the two states. Mowbray sees Maryland as a better place for riesling and a poorer place for semillon than Virginia, with chardonnay a problem in both states because of the generally warm climate. After a few minutes of discussion, Luchsinger and Mowbray agreed on the major difference in winemaking in the two states: Virginia wineries have more money. "Money is more important than what you grow," noted Luchsinger somberly.

No one, however, remembered to tell the wineries that chardonnay was a problem, and fully half of the winemakers present produce chardonnay, including Mowbray himself, whose small production inhibited him from bringing samples. Of those present, Byrd, both '79 and '80, was particularly impressive.

Also no one remembered to tell the Virginia winemakers that their climate was not well suited for riesling. Among the best and most popular wines were rieslings from Virginia. Rapidan River Vineyards from Culpepper poured two, one dry and one with medium sugar. The low alcohol (10.5%) and otherwise Germanic style are the doings of Dr. Gerhard W. R. Guth, a surgeon from Hamburg and the winery's proprietor. He was emphatic that good riesling could be produced in Virginia. Ingleside was the winery responsible for the other fine Virginia riesling.

Those seeking a new wine experience could sample ravat from Glenora Wine Cellars in Dundee, N.Y. Mike Elliot, Glenora's winemaker, described ravat as a hybrid of uncertain ancestry, probably with pinot noir among its forefathers. A fruity wine with good flavor and a hint of fizz, it is grown only by a few New York vineyards.

To customers pausing in front of his wines, John Crouch of Allegro Vineyards in Brogue, Pa., explained how it took him four years to find the ideal spot in which to grow vines. His well-balanced cabernet sauvignon is made with 15 percent merlot and a dollop of cabernet franc. Another vineyard using merlot and cabernet franc in its cabernet sauvignon is Ingleside, which attributes the blending to its Belgian winemaker, who would have it no other way.

This readiness to blend merlot and cabernet franc with cabernet sauvignon a' la bordeaux is in contrast to the usual California practice of making cabernet a 100 percent varietal. This difference, among others, prompted one winemaker present to suggest that within a decade East Coast wines may have more in common with those of Europe than of California.

Of the other participants, Meredyth Vineyards in Middleburg, Va., presented, among many wines, a superior oak-aged villard blanc. Rounding out the list of wineries were Nissley Wine Cellars of Baimbridge, Pa., Naylor Wine Cellars of Stewartstown, Pa., Boordy Vineyards of Hydes, Md., and Wagner Vineyards of Lodi, N.Y.

Probably because of the superb weather, the crowd was modest in size, rarely exceeding a few dozen. Some wine was sold as well as given away, but not enough to satisfy some who participated. There was one big plus for everyone, however. "It gave us a chance to talk and compare notes," one winemaker observed. "You never can tell what you will learn from someone making wine."