Watch the Clone

UC Davis' Heritage Vineyard project

“Geez, every grape’s the same!” winemaker Scott Harvey remembers musing to himself the first time he peered into a hopper full of Napa Valley Cabernet Sauvignon. “No wonder people like making wine here!”

Harvey was used to making Zinfandel in the Sierra Nevada foothills, and had every reason to feel spoiled in Napa. Unlike those perfectly uniform clusters of purple Cabernet grapes, Zinfandel tends to vary within each cluster, and clusters vary within each vine. To make matters more complicated, the unique heritage of each vineyard may affect the flavor as well. At its best, Zinfandel makes for a devilishly good wine, but as with all things wine, the devil is in the details.

Because similarity in Zinfandel grapes is so desirable, most modern vineyards are planted with clones, nearly identical grapevines that were propagated from one original vine, or even one bud of one vine, that has been certified disease-free by California’s Foundation Plant Services (FPS). When, in earlier days, farmers just took cuttings from one vineyard to plant a new one, each generation had the potential to differ slightly from the last. For well over a century, that’s how Zinfandel was planted. Some vineyards became renowned. Others ended up being dumped into a sea of White Zinfandel.

But how much of that is due to the vine’s parentage vs. its climate, or to a particular winery’s craft—in other words, to nature vs. nurture? The Heritage Vineyard project aims to find out exactly that.

In the 1990s, the trade group Zinfandel Advocates and Producers (ZAP) persuaded UC Davis to collaborate on a plan to collect samples from some of California’s best Zinfandel vineyards. A key participant was Joel Peterson, whose Ravenswood Winery helped spur Zin’s resurgence in the 1980s.

“We’re really on the verge of a new era for people who choose to plant Zinfandel,” says Peterson. After scouring the state for vineyards that were planted before 1930, the group submitted dozens of samples to the FPS, which were then planted in the UC Davis experimental plot in Oakville. This way, the variable of climate could be eliminated.

Drum roll, please? Not so fast. As intoxicating as it must be for someone who’s devoted his life to teasing out the complexities of Zinfandel, Peterson is realistic about the near-term prospects. “It’s one of those projects that takes a lifetime, ultimately,” he admits. “It’s not like raising rabbits or cabbages.” Just to get to the point where the wine from one clone can be submitted for evaluation can take from four years up to a decade. “These projects tend to have a long life, and probably take a few generations of humans,” Peterson says.

Still, progress is being made. “I would say there are two broad differences,” says Peterson. “There’s a group that produces wines that are more claret-like, that have more structure, a high-toned character, bright fruit, higher acidity and good color. Then there’s another selection which produces more fruity wines that tend to be softer, that tend to have more of what I categorize as a sweet fruit character.”

Meanwhile, a portion of the grapes are vinted by a different winemaker each year. Sales of this Heritage Vineyard blend benefit ZAP’s ongoing research efforts.

In 2011, winemaker Scott Harvey was up at bat. Having grown up with his grandfather’s 1869 vineyard, helped build Amador County’s Renwood Winery and launched successful brands like Ménage à Trois, Harvey knows a thing or two about Zinfandel. Yet his early schooling in one of Germany’s few red wine regions helps inform a more European style. In Zinfandel, Harvey looks for ripeness, but not too much. He wants a wine to tell the story of where the grape is from, “and the riper they get, the less ability they have to tell you those stories,” he says.

The 2011 vintage gave him the perfect opportunity. Tasted from a barrel in Harvey’s production space—coincidentally enough, part of a complex that once pumped out Sutter Home Winery’s Olympic-sized volumes of White Zinfandel—the new wine shows bright red fruit flavors of cherry and raspberry.

As adept as he is after 38 years of walking Zinfandel vineyards, Harvey can’t say which out of the several acres of identically pruned, head-trained vines are his grandfather’s “1869” clone. The vines are planted in a repeating pattern in the interest of science, and to dissuade clone-rustlers, their identities are a closely guarded secret. To this generation, at least.

Sonoma County Library