Zinfandel — rightly or wrongly called America’s grape — is going back to its roots.

Once a cultivar of unknown origin, zinfandel within the past decade has been genetically tied to an ancient Croatian grapevine, crljenak kastelanski, which had almost died out. Scientists also determined in recent years the Italian grape primitivo and zinfandel are one and the same.

And now, with the help of Croatian agronomists, this distinct grape variety with Old World pedigree is being replanted throughout Croatia’s Dalmatian countryside.

“We believe zinfandel will become one of the leading red varieties in Dalmatia in the next 10 years,” forecast Ivan Pejic, geneticist with Zagreb University’s Agriculture Department during a visit here earlier this  week.

Pejic and another faculty member of the university’s agriculture department, viticulture specialist Edi Maletic, dropped by Grgich Hills Cellar to present the latest information on zinfandel and the revitalization effort in their homeland.

Not only did they show photos of experimental vineyards where zinfandel, primitivo and crljenak kastelanski (pronounced tsirl-YEN-nock kash-teh-LAHN-skee) were planted side by side, they brought along wines made from the first crush. Also included in this special tasting were wines made from another popular Croatian grape, plavac mali — a variety now believed to be a mutation from the ancient crljenak kastelanski.

Field research

In order to fully understand the importance of what’s taking place, one needs to know that for years, vintner Mike Grgich (a Croat who fled his Communist-run homeland as a young man and settled in the Napa Valley) maintained that the flavor profiles of zinfandel and plavac mali were so similar that they had to be the same grape. He was certain the roots of zinfandel were in Croatia.

For years, people listened. But nobody did anything — that is until the respected winemaker bent the ear of Carole Meredith, faculty member of UC Davis viticulture and enology department.

Meredith was aware that although America claimed zinfandel as its own that the cultivar came to the United States in 1952 from somewhere in the former Austro-Hungarian empire. No one knows how the name zinfandel came about, although there are plenty of speculative tales.

The UC Davis scientist also knew that as early as the late ’60s there was serious talk about Italy’s primitivo and zinfandel being one and the same.

Meredith made her first trip to Croatia’s vineyards 11 years ago, eventually hooking up with Pejic and Maletic on a quest for the birthplace of the zinfandel vine.

She would learn that grapes had been planted on Croatia’s island of Korcula as early as the 4th century B.C. Before phylloxera wiped out substantial acreage early in the 20th century, Croatia had more than 500,000 acres of grapevines. There’s barely one-fifth that amount cultivated today. (The Croatian agronomists have identified 250 grape cultivars in Dalmatia, about half of which are native to the region.)

Meredith was eager to see if plavac mali, as Grgich believed, was indeed the parent of zinfandel. With help from her Croatian counterparts, Meredith collected 150 vine samples. She was able to conclude that zinfandel and plavac mali had different genetic profiles, but that they were close relatives. At the time, she told the world “same church, different pews.”

Pejic and Maletic continued the search and in 2001 performed a DNA test on a leaf sample from a vineyard not far from Split, a picturesque city on the Dalmatian coast. Bingo — it was a match. Eager for a second opinion, they sent other samples from the same vine to Meredith, who confirmed that zinfandel was identical to the vine with the unusual name, crljenak kastelanski.

“We now know that zinfandel, primitivo and crljenak kastelanski are one cultivar with three different names,” Pejic told wine writers, authors, vintners and growers at Grgich Hills Cellar on Tuesday.

To date, “We’ve found 25 crljenak kastelanski vines in Dalmatia and we’re propagating this variety. On the  island of Hvar we have zinfandel, primitivo and crljenak kastelanski planted side by side in an experimental vineyard. We want to see how each will do on the same plot of land, in the same climate.”

Pejic hoped the industry would wait until researchers had reached some conclusions from the experimental plot. However, Croatian growers and winemakers responded by planting 185,000 vines — some zinfandel from New World cuttings, some Italian primitivo — and are waiting for cuttings from approved crljenak kastelanski vines.

Non-stop research

The University of Zagreb faculty members say that zinfandel (or crljenak kastelanski) “was a major variety in Croatia five centuries ago.”

They say the grape — called tribidrag in the 15th and 16th centuries — was an important export as records indicate large quantities were shipped to Venice.

For some unknown reason, crljenak kastelanski disappeared in large measure several hundred years ago, Pejic said. What survived, he said, was a mutation —a cousin, if you will — called plavac mali.

Zinfandel, or crljenak kastelanski, he revealed, along with another indigenous Croatian grape, dobricic, are the parents of plavac mali.

While flavor profiles are similar, there are several distinctions between plavac mali and crljenak kastelanski — most notably bud break and ripening. Crlejenak kastelanski ripens early, plavac mali much later in the growing season. The latter grape does best in a hot climate, in vineyards facing the sea.

“There is a high demand for red wines in Croatia,” Maletic said. “So we think zinfandel will be a welcome addition to the choices available for planting.

“Our experimental vineyard should tell us if there is any difference between zinfandel (from Old World cuttings), primitivo (from southern Italy) and crlejanek kastelanski growing in the same place.”

The wine world awaits the results.

Tasting the wines

The visitors brought along seven wines for the group to taste, along with a pair of zinfandels from Grgich Hills Cellar.

Three of the wines were plavac mali, including one made in the cellar owned by Grgich located on the Peljesac peninsula near Dubrovnik.

Plavac mali produces dense wines high in tannins, alcohol and color that can age well. The best known of these wines made from plavac mali grown in two specific sites, Dingac and Postup.

The example from producer Mara Mrgudic came from Postup, from a site facing the sea at the western tip of the peninsula. A soft, fruit example, it displayed ample red fruit and spice, and was typical of the variety when it comes to density and tannins. From the Bura winery in Dingac was a more balanced, concentrated example with similar flavor profiles. It tasted like a more expensive wine and a check showed that it retails for more than $50 a bottle on the East Coast.

The plavac mali from Mike Grgich’s cellar on Peljesac was more aromatic, more astringent and could be labeled a California-style wine. It had a lovely floral nose but not as much red fruit as the other wines.

Using primitive grafts, Marinovic and Djuric made a 2007 crljenak kastelanski in their cellar near Dubrovnik. It exhibited expected zinfandel characteristics — lots of spice, both blueberries and blackberries on the palate, along with an extra shot of new barrel oak.

The faculty of the Agriculture Department at Zagreb University made a wine (just 225 liters), the first from the new crljenak kastelanski plantings on the island of Hvar. Exhibiting oodles of ripe black fruit, this was an outstanding well-balanced wine with a lingering plum finish.

Also from the island of Hvar, Zlatan Pleknovic made a dessert wine from the new plantings. It was described as “an old Mediterranean style wine, one that might have been served in Roman times.”  A late harvest wine produced from a substantial amount of dried grapes, it had the quality of a Port but without the heady alcohol.

Grgich Hills Estate 2006 zinfandel, made from vines planted in 1998, showed off its bright Calistoga fruit and vineyard sunshine — plus a lovely mix of black cherries and spice.

Grgich Hills Estate 2005 Miljenko’s Old Vines zinfandel is a rustic zin made from vines dating to 1889. Fewer than 300 cases are produced, said cellarmaster Ivo Jeramaz. Flavors of both black cherries and blackberries coat the palate. It’s a classy, concentrated zinfandel that speaks to its heritage and the man who has taken the variety back home.