A warm Indian summer may have saved Pennsylvania's grape crop this year after bad weather left vineyard owners questioning the fate of their harvests, say a winegrape expert with Penn State University.

"The streak of October weather that was warm and dry really helped to get the late whites and reds fully mature," says Mark Chien, statewide viticulture Extension educator based in Lancaster County. "For those winegrape growers who had the patience and nerve to continue to let their fruit hang on the vines, that was the reward."

Grape growing in Pennsylvania is a chess game with the weather. In 2008, growers there came out ahead, Chien says. "The crops have benefited from smart harvesting strategies, a lack of frost up through October and few problems with birds and bees."

Still, the 2008 Pennsylvania vintage saw some less-than-ideal conditions earlier this year, according to a Penn State news release. Complications from hurricanes, hailstorms and overall weather patterns threatened the year's wine quality.

"We had a dry August across much of the state, but hurricanes made the weather unreliable," Chien says.

Traditionally, years that are dry and warm make fine wines, while wet, cool years pose more difficulty, he says.

"Vineyards require well-drained soils and little rain, particularly during the last third of any vintage, which is the most critical time for wine," Chien says. "It is during this time that the vines focus on ripening the fruit and not on growing leaves, a process hindered by rain."

Rain also dilutes juice concentration within the grapes and can lead to disease problems with the vines, he says. In addition, late red varieties need on the vine, often until early November, creating prolonged concerns about rainfall.