Just as champagne and sparkling wine sales go up dramatically in the month before New Year’s Eve, nearly one-third of all kosher wine sales take place in the two months before Passover.

So said Jay Buchsbaum, vice president of the Royal Wine Corp. The New York-based Buchsbaum was in California recently to show off the Herzog Wine Cellar’s gleaming new winemaking facility, tasting room and kosher restaurant in Oxnard to a group of visiting journalists.

The Royal Wine Corp., which oversees Baron Herzog, is the largest producer, importer and distributor of kosher wines in the world. Its repertoire includes labels from Israel, Australia, Chile, France and the United States.

The Herzog family has been in the winemaking business since the 19th century, with Philip Herzog making wine (both kosher and nonkosher) in Slovakia for Emperor Franz Joseph. The Emperor appreciated Herzog’s wines so much that he bestowed upon him the title of Baron.

The Herzogs survived World War II by hiding in the countryside. However, the rise of communism propelled them to immigrate to the United States. Eugene Herzog took a job at a small kosher winery, making sweet wine out of the Concord grape. Eugene was able to take over that business in 1958, and he named the company Royal Wines, in honor of his grandfather.

While they are also the makers of Kedem grape juice, the second largest grape juice manufacturer in the country, they have largely moved on from the Concord grape. Baron Herzog features all California varietals, from Chardonnay to Zinfandel.

In 1985, the Herzogs began their operations in California. But for the past two decades, they did not have a home of their own, and rented space at other wineries.

That changed last year when the Herzog family built its own winery in Oxnard, complete with tasting room and kosher restaurant, Tierra Sur.

For wine to be kosher, it must be handled by Sabbath-observant Jews from the time the grapes are crushed through the bottling process. This means that at other wineries, there was always the danger of a non-Sabbath observant Jew touching the wine, making it nonkosher.

There is no danger of that now, even though the head winemaker, Joe Hurliman, is not Jewish. When he wants a taste from a barrel, an observant employee must draw it from the barrel and hand it to him.

Located at the southern point of the Central Coast of California, Oxnard is 40 miles south of Santa Barbara. The 77,000-square-foot winery is surrounded by strawberry fields, not grapevines. None of the grapes used in the wine are locally grown; they are all bought from growers throughout the state, and Hurliman visits the various vineyards, making sure they are grown to his liking.

Buchsbaum explained that before, there was always the worry that the wine could somehow be contaminated by being made in a facility that also produces nonkosher wine. Here, they can concentrate only on the winemaking itself, since the whole facility is kosher.

“Joe gets to call the shots,” said Buchsbaum. “And this new facility increases our ability to emphasize our reserve wines.”

Hurliman, who has been with Herzog since 1988, sees the kosher laws as a challenge, and feels that in some ways it works to his advantage, as the staff handling the wine must be trained about the winemaking process in a way that staff at other wineries are not.

The winery had to be built close enough to an observant Jewish community to accommodate the workers, most of whom live in nearby Thousand Oaks.

Visitors to the winery are offered a bird’s-eye view of the proceedings down below. They cannot get up close, but they can look down on the barrels, the fermentation room and the bottling process, as the bottles go down the assembly line and are filled, corked, labeled and boxed.

The boxes are then sealed and taped by a special machine with an “arm” that pushes the boxes in the proper direction to be stored until shipping.

The tasting room opens daily at 11 a.m. except for Saturday.

J. staff writer Alexandra J. Wall was a recent guest on a trip sponsored by Herzog Wine Cellars.

Herzog Wine Cellars, 3201 Camino Del Sol, Oxnard. (805) 983-1560. www.herzogwinecellars.com.