NAPA, Calif. — Ernie Weir began working as a viticulturist at Domaine Chandon, the Napa Valley arm of the prestigious Champagne house Moet & Chandon, in 1973 at a time when an American wine renaissance was taking shape. It also was a period, says Weir, when our country experienced a resurgence in cultural and ethnic pride. While these two simultaneous trends may seem unrelated, they linked together to shape Weir’s future as one of the world’s top kosher winemakers.

In fact, it was the combination of these trends that made him question the following: If the French, Italians and even Californians were proud of dry, complex wines that they could serve with meals, why weren’t Jews? After all, Jews had been making wine since biblical days and there’s absolutely no reason why kosher wine had to be sweet or consumed only during kiddush, seder or other ceremonies.

“Jews aren’t hiding any longer. We’re out of the closet. Why aren’t there good kosher wines?” Weir thought. A light bulb went off. He wanted to be the first American producer of premium kosher wines. So the idea behind Hagafen Cellars, the first kosher winery in California’s prestigious Napa Valley, was born.

Today, wines from Hagafen — Hebrew for vine — often win scores in the 90s along with rave reviews in the Wine Spectator, New York Times, Washington Post and The Wall Street Journal.

Respected British wine critic Hugh Johnson has described Hagafen as “one of the first serious California kosher producers” and even the late Daniel Rogov, the famous Israeli wine critic who died last September, was a great fan of the Hagafen label. “Some may think that shipping kosher wines to Israel is somewhat akin to selling ice to Eskimos, but in this case the Hagafen wines are a most welcome addition to local shelves,” Rogov wrote in a 2008 article published in Haaretz.

With all that praise, one might think that Hagafen is one of those hoity-toity, exclusive wineries in Napa with a posh sampling room and a $50 tasting fee to match. While Hagafen is a well-respected boutique winery-even a cult winery to some-due to its high quality, small production and prestigious Silverado Trail address, it’s about as down-to-earth as it gets.

In fact, Hagafen is so modest and farm-like, that Aine Kelly, assistant hospitality coordinator, ties balloons to the Hagafen sign at the start of the winery’s long driveway so that tourists can find the place. And if you take a seat in the winery’s cozy patio, Kelly’s little dog Lily Rose might just make herself at home in your lap while Lola the cat basks in the sun.

It’s the kind of bucolic, laid back setting that makes one dream of owning a winery. But making a winery successful takes a lot of hard work, knowledge, creativity and in Weir’s case, chutzpah.

Since Weir is not Orthodox-he was raised Conservative and is now a member and past president of Napa’s only Reform temple-why did he choose to make kosher wine?

“I approached it from a cultural point of view,” he said. But he also explained that while he wanted to honor religious traditions, he also was searching for a new marketing opportunity. By establishing a high-end kosher winery in Napa he’d be creating a new niche.

He realized that many observant Jews in the United States would follow the wine drinking trends in the rest of the country and would be looking for top quality, dry wines to accompany their meals or sip as an aperitif.

“Jews were starting to switch from sweet to dry wines. There was a misconception that being kosher meant compromising the quality. But there’s nothing about making kosher wine that means you have to compromise, ” he said.

So for 18 years, while Weir was working at Chandon, he ran Hagafen as a side business. Hagafen was founded in 1979 and initially used facilities at a different winery. Weir began buying land in the Silverado Trail and opened the current winery in 2000 just yards from the Oak Knoll district and less than a mile from the famous Stags Leap district. The stand-alone tasting room opened in 2002.

In addition to its primary Hagafen label, the winery produces a premium label called Prix and a value driven line, Don Ernesto. The winery offers a full selection of blends and varietals including cabernet sauvignon, cabernet franc, chardonnay, merlot, pinot noir, roussanne, Riesling, sauvignon blanc and Syrah. Its portfolio includes a 2007 Cuvée de Noirs sparkling wine that was served at President Barack Obama’s annual White House Hanukkah dinner last December.

Although Weir is both owner and winemaker, kashrut rules bar him from personally handling the juice from the time the grapes are crushed until after they are flash pasteurized because he is not an observant Jew. The flash pasteurization process makes the wine “meshuval” allowing it to be handled by non-observant Jews as well as gentiles.

During the wine making process, Weir brings in observant workers provided by the Orthodox Union in Los Angeles, who are supervised by a mashgiach from Berkeley. Blue seals carrying the OU hecksher are visible on the barrels and can only be removed by the mashgiach.

Most of the tourists visiting the winery are oblivious to those seals. In fact most of them probably aren’t Jewish. Many come on the recommendation of tour guides who contend Hagafen is an “authentic” type of winery and should be experienced.

“All sorts of people come here and most have no idea the wine is kosher,” said Weir, who often helps out in the tasting room and chats with visitors. “The majority think I’m Mr. Hagafen.”