(Tri-CityHerald) - Many of the delicious flavors in red wine are created by limiting how much water the grapes get. It turns out that for white wine grapes, severe water restriction can do more harm than good.

That’s why Washington State University scientists are excited about new research that suggests grape growers may want to try a new irrigation option that falls between full watering and the restricted water strategy commonly used on red grapes. The findings could help growers improve white grape quality without wasting water — an attractive combination for vineyards in drought-prone regions such as the Yakima Basin.

Until now, irrigation research has focused on red grapes, said Yun Zhang, a post-doctoral researcher at Washington State University’s Irrigated Agriculture Research and Extension Center in Prosser. “But the kinds of flavors consumers enjoy in white wine and the wine-making process is different, so we thought maybe the irrigation might need to be different as well,” she said.

For red wine, the desired bitter and aromatic compounds in the grape’s skin are magnified if the fruit is more exposed to the sun and kept small — both of which are accomplished by midseason water restrictions known as deficit irrigation, which limits leafy shade and growth.

But with white grapes, too much sun can lead to unwanted bitterness as the plant makes its own sunscreen chemicals, said Jim Harbertson, an associate professor at WSU who studies wine chemistry.