IT IS IRONIC that the major wine function on the East Coast each year is not an homage to rare, old vintages, but a showcase for immature wines called the California Vintners Barrel Tasting Dinner. The fifth annual edition of this event was held Monday at the Four Seasons restaurant in New York City.

A "barrel tasting" is not, as one wag suggested, an occasion where people chew on various species of wood. It is an opportunity to taste young wines that have not yet been bottled. (That some young wines are so filled with tannic acid that they taste like wood is beside the point.)

Usually such tastings are conducted in the dark cellars of wineries. Not this one. Nearly 200 persons, an elite of the wine world plus some prominent food personalities, gather at New York's most glamorous restaurant. Each new wine is accompanied by an older vintage from the same winery. Through the long evening (4 1/2 hours this year) a series of original food creations matched to the wines are served.

General Asher, the British-born merchant and wine writer, conceived the tasting as a way to promote the image of California's so-called premium wineries in the East. At that time (1976) there was a good deal less acceptance of California wines on this coast than there is now. Asher's idea was to bring the winemakers from selected wineries as well as the wines. The evening would be partly work and partly social. Although the social aspect has proven dominant, the vintners haven't suffered. Scholarly and personable, they are a fine advertisement for their craft. Also, unlike most European winemakers, they are fluent in English.

This year the new wines were from the 1979 vintage, a large harvest whose great promise was dampened by heavy rainfall and high heat in the vineyards north of San Francisco. Four pairs of chardonnay wines led off, followed by two pairs of sauvignon blanc. After an intermission, three pairs of pinot noir and three of zinfandel were presented. Finally, after another intermission, there were three pairs of cabernet sauvignon.

If there was a wine of the evening this year, it probably was in the first pair. John Trefethen of Trefethen Vineyards presented his 1976 chardonnay along with a cleverly labeled sample of his 1979 wine. the 1976 had already been singled out as a winner in a competition in Europe. While no votes are taken at the Bartel Tasting, it was widely applauded for its streamlined elegance. Still vigorous, the wine will benefit from countinued aging for those lucky enough to have purchased some.

The other chardonnays were Chateau, St. Jean (1979 and 1978 from the Robert Young Vineyard), Lambert Bridge (1979 and 1978) and Burgess Cellars (1979 and 1973). The Trefethen, with lots of fruit and acid, and the Burgess, stocky and rough with a beautiful color, made the best impressions among the young wines. The Lambert Bridge pair were the most unusual wines of the group, with a distinctive, almost flowery nose.

During the sauvignon blanc presentation there was a lively back and forth between Joseph Phelps and Cary Gott of Montevina Vineyards, Phelps championing finesse and Gott speaking forcefully on making wines of body and "power." The Phelps Vineyard's wines, a '79 and '78, with about 20 percent semillion blended in to mitigate the "austerity" of sauvignon blanc from the Napa Valley, gained an edge with this taster.

With the chardonnays, Four Season's chef Seppi Renggli, offered a soamon mousse topped with caviar, followed by Dungeness crab legs in cilantro (chinese parsley) batter and a cassoulet of codfish. The sauvignon blancs inspired a cervelat of shad, each sausage-like round slice topped with a sauce that incorporated shad roe. A fantasy version of pepper pot soup, highlighted by barely cooked pieces of red and green sweet peppers, came on as a palate cleanser just before intermission.

As Gerald Asher noted, the common assumption that there is "no" pinot noir in California is wrong. The search for the "perfect" pinot noir has generated a great deal of enological research. But, like the Holy Grail, it has yet to be found, The Californians think they are getting closer, but a few Easterners found nothing they admire among the wines presented by Beaulieu Vineyard ('79 and '76), Sanford & Benedict ('79 and '77) and Kenwood Vineyards ('79 and '77). Legh Knowles of BV pointed out that his winery strives for smoothness and the wines did share that characteristic. The new wines from Sanford & Bendice and Kenwood were very difficult to unravel, but the '77 Sanford & Bendict may prove to be the ugly ducklyng of the group. Still without charm and marred by a cheese-like bouquet, it has richness and may put on a cloak of elegance in another year or two.

Ballotine of duck, presented on platters decorated with white ducks, was served with the pinot noirs.

Two of the landmark zinfandel wineries, Ridge and Sutter Home, came next. Ridge's '79 and '77 Shenandoah zinfandels both showed considerable fruit, but the '79 appears to be the heavier wine. Sutter Home's '79 has a deep, cherry-like color, but it will be some time before it begins to show the bouquet and impressive complexity of that winery's 1974. The most popular zinfandel, however, came from upstart Edmeades Vineyards in the Anderson Valley near Mendocino. It had an elegance the heavyweights in this class lacked.

The Four Seasons presented a rather gussied up beef pot pie with these wines, then ended the act with a delightful pear and ginger sherbert.

A trio of American cheese was presented with the cabernets. Chapellet showed its '79 and '73. Stag's Leap, another winery that emphasizes style ("richness without weight"), entered its '79 and '76. The final two cabernets were the '79 and '74 from Simi. Asher's prediction that we will see no even style of cabernet from '79 was underlined by these wines. The Chapellet seemed much lighter than is normal for this Napa vineyard, while the Stag's Leap had a strong herbaceous nose. Simi, which admitted to a "difficult" vintage, put forward a wine that had a good color but seemed far too soft at this early stage in its development. Among the older wines, the Simi was more impressive than its celebrated companions, perhaps because it came from a particularly strong vintage.

Somehow 200 miniature hot souffles, flavored with a maple and bourbon sauce, appeared to end the meal. No one asked for more wine.