Ravenswood hosts a harvest dinner starring its versatile, robust wine.

For a winery that specializes in America's so-called mystery grape, Ravenswood, in Sonoma, California, is anything but mysterious. In fact, its collective sensibility might even be said to fall well short of subtle. A prominently displayed photograph in the Ravenswood tasting room shows several winery employees wearing nothing but barrels. Then there is the monument in front of the winery that's inscribed "To err is human, to Zin is divine" and the notice scrawled on a chalkboard close to where the tours begin, "Today's lecture: How we put the red in red Zinfandel."

That's a joke. Ravenswood has never made white Zinfandel, the commercial concoction that has led many Americans to believe that Zinfandel is a white grape. Ravenswood specializes in red--some might say black--Zinfandel, which is crafted in a style that has inspired a rabid following among hard-core hedonists. The winery's unblushing motto is variously translated as Nullum Vinum Flaccidum, Pas de Vins Poules Mouillées, Kayn Nebbishy Vayn and No Viños sin Huevos. All of which constitute fairly liberal renditions of the slogan No Wimpy Wines.

It's an unconventional (and certainly unsubtle) phraseology, perhaps, but then little about Ravenswood is conventional. Even when the winery's founding partners, Joel Peterson and Reed Foster, gather their families for a celebratory harvest dinner, the meal is an unexpected pairing of lamb and Zinfandel. (Tony Najiola, Ravenswood's executive chef, prepared the dinner that follows.) After all, Cabernet Sauvignon is the traditional partner for lamb. But this match works, Peterson says, because the Zinfandels he creates are balanced and "consistent with classical winemaking standards, straddling the edge between those that are simple and quaffable and those that are so massive and powerful they're hardly drinkable beyond one glass."

Peterson, Ravenswood's maverick 51-year-old winemaker, president and co-owner, finds much about Zinfandel in general to please the American palate. "Americans tend to like things they can cozy up to right away, and Zinfandel has an exuberance of fruit, an intensity of flavor and a suppleness of body that are all very appealing." Zinfandel is also a quintessential American success story: "It was an unknown that came from somewhere else, went through multiple changes and finally became a success--America's first success, really, in fine wine."

Zinfandel--racy, spicy, berrylike and lush--immigrated to the United States from abroad under murky circumstances. Although its exact origins are not known (hence the mantle of mystery), it was the most popular variety of the California grape-planting boom of the 1880s. Originally touted as a candidate for the creation of fine domestic claret, it fell out of favor in the years following Prohibition and was relegated to the making of undistinguished jug wines. By the early Seventies, about the only people who appreciated Zinfandel's potential were such plucky individualists as those at Ridge Vineyards and home winemakers, one of whom was Peterson.

Peterson grew up in Point Richmond, a town on San Francisco Bay, where his father led a wine-tasting group that evaluated first-growth Bordeaux and other fine wines. Peterson sat in on these tastings as a child, and in his twenties he began writing and consulting about wine professionally. He later apprenticed with the legendary Joseph Swan and started Ravenswood with Foster, a real-estate broker and Harvard MBA who co-founded the Vintner's Club of San Francisco in 1973. The grape they chose, unlike most of their California peers, was not the classic Cabernet Sauvignon but the underappreciated American "native" variety Zinfandel.

Peterson explains: "I asked myself, 'What do the great European vineyards have in common?' First of all, they're dry farmed, with no irrigation. Second, their vines are trained to allow light and air to circulate and their yields strictly controlled so there aren't too many grapes per vine, diluting the flavor of the fruit. Third, and most important, their grape varieties and sites are ideally matched. As I looked around California, only one grape fit all these criteria: Zinfandel."

The wines that resulted--an array of bottlings from individually designated vineyard sites--are ripe, opulent, tannic and complex, acknowledged pacesetters in the revival of this once taken for granted grape. In fact, the amount of Zinfandel harvested in California has nearly tripled over the past decade, with prices rising almost as dramatically. California's top Zinfandels now rival the state's Cabernets in their exclusiveness and their priciness.

Of course, this didn't happen right away. When I worked in Peterson's cellar during the 1984 harvest, Zin- fandel was still an underdog and Ravenswood had only one full-time employee. (And it wasn't even Peterson, who was then working as a laboratory scientist at Sonoma Valley Hospital.) Today Ravenswood has 35 employees (more during crush) at its picturesque estate north of Sonoma, and Peterson oversees the production of some 200,000 cases per year.

"People have taken Zinfandel into their hearts," Peterson declares. "There are more wineries making better wines now than ever before. So we've got a kind of competition going, with lots of talented winemakers and grape growers competing for the Zinfandel grail, all aided and abetted by a public that's enjoying this strife within the business."

Somehow strife seems too harsh a descriptive for such a bounteous situation. "Don't you mean synergy?" a friend asks. Peterson narrows his eyes and shakes his head. "No," he answers. "That's too wimpy a word."

DAVID DARLINGTON, the author of Angels' Visits: An Inquiry into the Mystery of Zinfandel (Henry Holt).