Whatever the mechanism, it worked. The major lakes -- Canandaigua, Keuka, Seneca, Cayuga, Owasco -- are up to 650 feet deep, too deep to freeze over in winter, their sheer mass of water moderating the area's winter temperatures, making it possible to grow mainline grapevines farther north than usual.
Still, winery tours are far from the only attractions in the Finger Lakes.
On a given summer or fall day, a tourist could drive the length of one of the lakes, about 35 miles, visiting the wineries' tasting rooms, wine museums, gift shops and restaurants; pause for lunch at the Village Tavern in Hammondsport, watch a live glass-blowing exhibition at the spectacular Corning Museum of Glass, walk under a waterfall at Watkins Glen State Park, hike the North Country National Scenic Trail system, savor a gourmet dinner at restaurants old-fashioned or new wave, then settle in under a down comforter at a friendly bed-and-breakfast inn. There's also boating, perch fishing directly off the docks, fall foliage tours, professional auto races at Watkins Glen International Race Track, the old-fashioned Seneca County Fair, dining cruises on Seneca Lake, shopping in restored historical areas such as Corning's Historic Market Street and Hammondsport's Village Square.
Cultural activities are equally varied -- the National Warplane Museum, the Glenn H. Curtiss Museum of cars, motorcycles and airplanes, the Rockwell Museum of Western American Art, Broadway plays at the Clemens Center for the Performing Arts, concerts by the Syracuse Symphony, art and jazz festivals at wineries.
The Finger Lakes area has some big chain hotels -- the Radisson in Corning, the Ramada Inn in Syracuse. But many tourists prefer the bed-and-breakfast inns in restored 19th-Century houses -- Merritt Hill Manor in Penn Yan, an 1822 country estate once a stop on the Underground Railroad for escaping slaves; Rufus Tanner House, an 1864 Greek Revival farm house surrounded by sugar maple trees. And while the Finger Lakes restaurant scene hasn't reached the cutting-edge quality of Napa or Sonoma, it is moving in that direction. At Seasons Restaurant in Watkins Glen, chef Brud Holland, trained at the Vermont Culinary Institute, serves savory Creole oysters at $6.50; lobster-stuffed sole at $18.25 and hand-rolled gnocchi with spinach, Portobello mushrooms and romano cheese at $15.95, nicely matched by Dr. Konstantin Frank's soft, fruity Salmon Run Chardonnay.
At Red Newt Cellars on Lake Seneca, chef Debra Whiting is making pork chops stuffed with corn bread, rhubarb, walnuts and Swiss chard in a rhubarb sage sauce for $16.95, accompanied by a delicate, fruity Red Newt Riesling.
Still, the area's tourism future lies in its wineries. Overall, Finger Lakes wines range from world-class to primarily educational. But this means that, in an easy day's travel, a wine aficionado can taste the whole history of American wines.
Wine tastings are mostly free, with no reservations needed. Just show up and say hello, and the tasting-room folks will pour you tiny samples of their wines. It's de rigueur to swirl, sniff, slosh and -- unless you have a designated driver with you -- to spit.
Visitors are not required to buy anything, but if you taste a dozen wines and spend an hour at a winery, it would be nice to show your appreciation.
Unlike California's wine country, the Finger Lakes wineries can show you flavors from three distinctive eras of American wine.