PENN YAN, N.Y.

THE rain was falling again in the Finger Lakes, just as it had for much of September. The incessant precipitation was causing anguish as grape growers across the region weighed harvesting before optimal ripeness or risking the rot and mold that might come with waiting.

“This is a year that’s going to challenge everybody,” said John Martini, who owns Anthony Road Wine Company, on the shore of Seneca lake outside this village. The difficult climate, combined with a diverse combination of soils, makes the Finger Lakes one of the most unusual American wine regions. In the last decade or so, it has begun to show its enormous potential, as a small but growing number of producers makes graceful wines that stand in contrast to prevailing styles from the West Coast.

Fortuitously, the region hitched itself to riesling just as, in the last 10 years, riesling skyrocketed in popularity in the United States. Nowadays, top producers are not simply making good Finger Lakes rieslings, or good American rieslings. They are making seriously good world-class rieslings, in a multitude of styles.

Ravines Wine Cellars, one of the best producers, makes a wonderful dry riesling. I drank a 2009 and liked it so much that I bought a case, for just $14 a bottle. Ravines also makes a superb riesling from the Argetsinger Vineyard above the east bank of Seneca Lake. The lakes, deep claw marks left in the earth of west-central New York by glaciers moving south from the Hudson Bay, are as much a part of the winemaking culture here as tough vintages like 2001. The great depth of their waters nudges this otherwise inhospitable region to a level of bare tolerance for the fine wine grapes planted on the lakes’ slopes. In winter, the lakes almost never freeze, moderating harsh cold to protect the dormant vines, while in summer they air-condition the vineyards.