Sipping California wines for the benefit of public television and radio is the lure this coming Sunday at WETA's television studios in Arlington. Between 60 and 75 wines will be available to taste for those who pay a $5 donation. The lineup includes more than 20 wineries, perhaps the largest such showcase yet in Northern Virginia. It begins at 4 p.m. and continues until 7.

John DeLuca, president of the Wine Institute, will be on hand, as will winemaker Myron Nightingale of Beringer Vineyards. This is the 18th such charity tasting the Wine Institute, the trade association of California vintners, has organized for public television stations in various cities. WETA is asking wine buffs to make resservations as attendance will be limited. Mail a check for $5 to Sandy Johnson, WETA, Box 2626, Washington, D.C., 20013.

Among the wineries participating are: Almaden, Beringer, Calera, Christian Brothers, Clos du Bois, Franciscan, Gallo, Geyser Peak, Guasti, Korbel, Louis M. Martini, Paul Masson, Robert Mondavi, Pannonia, Quady, Rutherford Hill, Turgeon & Lohr and Wente Brothers.

From the "something's going on here we don't understand" department: A gnawing curiosity about Trader Vic's "pyramid wines" led me to conduct an experiment. Inspired by the pyramids of Egypt, and tales of their "power" to preserve foods as well as mummies, Vic Bergeron designed a triangular frame and placed wines on a suspended shelf within with the necks pointing north. I tasted these wines and, along with most others, preferred them over their exact counterparts in a blind tasting.

But who knew where the wines came from or how long they had been in the "pyramid"? So I asked Trader Vic's manager, Gregory Tu, to let me bring in several bottles from a private collection. He stored them in the pyramid. Two months later a group tried these wines blind against wines taken from the same cases and brought in for the tasting.

The results were a stunning affirmation of the claim that this form of storage speeds wines toward maturity. Three comparisons were made: The score in favor of the pyramid bottle of 1978 Chateau de Beaucastel, a white Chateauneuf du Pape, was 11 to 3; by a margin of 13 to 1 the tasters preferred the pyramid 1977 Carneros Creek pinot noir. The gap was narrower for the last -- and most mature -- wine, 1974 BV Private Reserve. The Pyramid bottle won 8 to 6.

Before running off to construct a pyramid, however, remember that what it appears to do best is to speed the maturing of young wines. With the white at Trader Vic's, for example, one was struck by the pronounced nose and fuller finish of the pyramid bottle. But collectors cellar their wines to preserve them, to prolong their lives, not to make them mature faster. Would a wine level out and live longer if kept in the pyramid, or continue its spurt toward senility? No one knows for sure. Still, if it does give a quick gloss of class to young wines (even those without pedigree), it may be a tool against wine price inflation. Wholesalers and retailers take note.

Let us now praise a few wines tasted recently. Korbel has introduced a sparkling Blanc de Noirs that deserves high marks for fruit and balance and should be considered among the best of the rapidly expanding list of California "champagnes." The much-heralded Jordan Cabernet Sauvignon 1976, the Alexander Valley winery's first vintage, shows a finesse and delicacy that set it apart from the mainstream of California cabernets. It should appeal to those schooled in the Medoc cabernet tradition. Estrella River's 1977 Chenin Blanc is a delightful aperitif wine, off-dry as they say, with a distinct suggestion of apricots in the bouquet. A real surprise is the non-vintage Dry Fu-Jin, a California product named to suggest a mating with Oriental foods. It is indeed dry and has a very clean finish. Don't wait for a meal with soy sauce. Much broader uses are appropriate.

There has been a lot of talk about a premier grand cru corkscrew called the Screwpull. It is a tall, handsome red plastic tool with a single, narrow bore and very effective coil. The Screwpull preforms brilliantly with both tight, new corks and tender old ones, but this corkscrew isn't the choice to make for ripping out a dozen corks in hal-a-dozen minutes. It can be found at Neiman Marcus, or may be ordered from Mike Allen, Box 1392, Houston, Tex., 77001. The price is $12.

More advice for the winelorn. A New Yorker named Albert E. Elseroad Jr., is editing and publishing "The Wine Buying Guide" six times a year. It contains commentary on wines at all stages of the price spectrum, using a rating key of execellent to poor, with a star indicating a "wise buy." It is not as wide-ranging as publications such as Robert Finigan's Private Guide to Wines or Robert Parker's Wine Advocate and seems to be more middlebrow in its approach. The wines in editions I have seen appear to have national distribution. Subscriptions are $7.50 a year. Write to The Wine Buying Guide, P.O. Box 1067, Long Island City, N.Y. 11101.