Like a lot of other winemakers in Napa Valley, Stacy Clark belongs to a tasting group that convenes every month or so to evaluate their wines and to swap information about grape sources, fermentation techniques and so on.

Sauvignon blanc was the topic of one such meeting last year. Not long before, Clark had joined Charles Krug Winery of St. Helena as its new winemaker after nearly 25 years at Pine Ridge Vineyards in the southern reaches of Napa Valley.

"We'd bring a wine we'd worked on, to taste and to talk about," Clark said.

Trouble was, she hadn't yet made a sauvignon blanc at Charles Krug. "I had to go out and buy a sauvignon blanc because I didn't have one," she added.

She won't have to do that the next time her tasting group takes up sauvignon blanc. With last fall's harvest, she made her first sauvignon blanc at Charles Krug Winery. It came off an unusually difficult growing year in Napa Valley – late spring rains followed by an atypically cool and damp summer. Charles Krug's sauvignon blanc, ordinarily harvested in mid-August, wasn't picked until September. The crop was down 30 percent, the sugar content of the grapes was off 6 percentage points. Clark and her crew fretted over whether the fruit was ripe enough for a decent wine, and whether it might be marred by mold from early fall rains.

Despite the challenging nature of the vintage, the Charles Krug Winery 2011 Napa Valley St. Helena Sauvignon Blanc is a solidly structured interpretation, its flavor running from grapefruit, papaya and mango to melon, grass and lime. Its acidity is refreshingly crisp, demanding that the wine be paired with shellfish. Overall, it's a zesty summer wine, straightforward and dry, with a lean yet sturdy build.

While Charles Krug Winery is best known for cabernet sauvignon and chardonnay, it has a long history of treating such second-tier varietals as sauvignon blanc and chenin blanc with affection and daring.

Earlier this year, when Peter Mondavi Sr. was inducted into the Vintners Hall of Fame at the Napa Valley branch of the Culinary Institute of America, he was recognized for the numerous technological innovations he introduced at Charles Krug Winery over the previous six decades.

(Charles Krug Winery, founded in 1861, is Napa Valley's oldest winery. In 1943, Cesare and Rosa Mondavi bought the facility for $75,000. With Cesare's death in 1959, Rosa took over as president, with assistance from her sons, Robert as general manager, Peter as vice president. In 1966, after he left the family business, Robert moved a few miles south to establish his own eponymous winery.)

Even before he took an active role at the family winery, Peter Mondavi Sr. was working on ways to improve winemaking. In 1937, as a graduate student in enology at the University of California, Berkeley, he researched the cold fermentation of white wines.

Up to that time, white wines in California generally were fermented at comparably high temperatures, exposing them to the influence of oxygen and restricting their fruitiness. Mondavi's subsequent use of the technique and of sterile filtration at Charles Krug Winery so enhanced the cleanliness, clarity and crispness of California white wines that the methods quickly were emulated throughout the state's wine trade.

For nearly seven decades Peter Mondavi Sr. has continued his experimental ways at Charles Krug Winery. He was the first to release chenin blanc as a varietal. He was the first to install glass-lined steel tanks, thereby better showcasing fruit, slowing maturation of wines and prolonging their lives. He was an early advocate of the centrifuge and of fermenting chardonnay in oak barrels.

But his most significant contribution likely was his early research and advocacy of the cold fermentation of white wines to preserve their freshness and varietal character. Stacy Clark was well acquainted with the techniques from her work at Pine Ridge Vineyards, where a fruity and sharp blend of chenin blanc and viognier is the winery's most celebrated white wine. (The chenin blanc, which constitutes most of the wine, is grown at Clarksburg in the Sacramento-San Joaquin River Delta.)

The sauvignon blanc is the first wine to be released from Charles Krug Winery's 150th anniversary vintage. So what has Stacy Clark's tasting group had to say of her first sauvignon blanc at Charles Krug Winery? For that, we'll have to wait a bit longer. "They haven't tasted it yet," she said.

Charles Krug Winery 2011 Napa Valley St. Helena Sauvignon Blanc

By the numbers:13.9 percent alcohol, 6,100 cases, $18.

Context: "At the moment, it's my house wine," said Stacy Clark. She especially likes it with melon wrapped in thin slices of prosciutto. Lemon chicken with capers and mushrooms; phyllo triangles filled with goat cheese seasoned with lemon zest; flatbread topped with feta cheese, olives, lemon and thyme; sautéed shrimp seasoned with Thai ingredients; and cracked crab, oysters and sushi are other possibilities.

Availability: Total Wine & More, BevMo and Rodney's in downtown Sacramento stock the wine. It's also available at the restaurants Florez Bar & Grill, Riverside Clubhouse and 4th Street Grille, and through the winery's website, www.charleskrug.com.

More information: The winery's tasting room, 2800 Main St., St. Helena, is open 10:30 a.m.-5 p.m. daily.

Editor's note: A photo caption has been changed to correctly identify Peter Mondavi Sr.

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