The rising popularity of California wine abroad had UC Davis viticulturist Dr. James Wolpert, far left, standing in a Napa Valley vineyard earlier today explaining to three European wine distributors how viticultural practices affect the nature of zinfandel.

The three, from left, were Carin Widoff and Kajsa Ekman, both of Stockholm, and Eric Remlinger of Nuits-Saint-Georges in Burgundy. All three distribute imports throughout northern Europe, where sales of California wines are increasing, thus their visit here to get a better grip on releases they are adding to their portfolios.

Their visit to the UC Davis Oakville Experimental Station in Napa Valley included a tasting of California zinfandels as well as a trek through the station's Heritage Vineyard, devoted to zinfandel vines grown with budwood gathered from some 90 vineyards about the state, several of them ancient and endangered.

Like some Californians, the three Europeans were taken aback by the high alcohol levels of a few of the zinfandels they tasted. In Sweden, noted Ekman, consumers just don't find such potent wines unless they are dessert wines; the government, she added, restricts table wines with more than 15 percent alcohol.

The three, however, quickly warmed to the heftier zinfandels. "I was surprised that the wine I felt was most balanced and elegant had more than 16 percent alcohol," said Remlinger. "The French view is that too much alcohol is a problem, but here the alcohol belongs to these wines. This is a very sunny and warm climate."

Their next stop, San Francisco, where the climate also may be sunny, though probably not as warm as what they found in Napa Valley today.