Mystery achievement: Sirah IS Syrah

The next time you find yourself driving through Northern California’s wine country, keep an eye out for living treasures.

They’re easy to spot, typically standing in ranks like an army of green-haired gnomes preparing to charge down the hillside. Each short, stout vine has a different shape, with three or four gnarly arms twisting out from its trunk. The wood is split and the bark hangs off in strips; spiders crouch under patches of moss and lichen that decorate each figure like badges of honor, and lizards bask in the knobby crooks.

On closer scrutiny, the green-haired gnomes appear to be bearing gifts: a few fat purple clusters of grapes, the very essence of California wine.

Petite Sirah and Zinfandel, which are often planted together in “field blends” in Sonoma County and the Sierra Nevada foothills, are California’s heritage grapes. “Pet” and “Zin” are synonymous with California wine, and practically with each other. They have been grown here longer than any other fine red wine varieties, and many vines planted well before Prohibition are still yielding highly prized wine (by contrast, most of California’s Cabernet Sauvignon was planted during the 1980s).

But for all their familiarity to Californians, both Petite Sirah and Zinfandel are grapes of mystery. They appeared here during the mid-19th century without any kind of paper trail by which their origins could be documented. No Vitis vinifera (wine grape) vines are indigenous to the New World, so Pet and Zin, like all Americans, must have come from somewhere else.

But where? For all anyone knew, they had been left behind in California by extraterrestrial visitors. Until this year, the wine world accepted as doctrine that Petite Sirah had nothing to do with the “true” Syrah of France’s Rhone Valley. In the ‘80s it was suggested that it might be an obscure French variety called Durif, but that hypothesis could not be supported by any of the testing techniques available then.

Now, the century-old mystery of one of California’s oldest grape vines has finally been pierced. At long last, we know the true identity of Petite Sirah. Cutting-edge DNA analysis by UC Davis plant geneticist Carole Meredith has confirmed that most of the California vines called Petite Sirah are in fact distant relations of true Syrah. It is descended through the little-appreciated Durif grape, which is itself descended from Syrah and another little-known grape called Peloursin. A small percentage is actually Peloursin itself, with a few other varieties--including the “true” Syrah--mixed in.

Meredith says Durif was either hybridized or selected by the rather obscure Dr. Durif, an agronomist who worked in southeastern France during the 1880s. She has established that the true Syrah is most likely the pollen parent, or father, and Peloursin the mother.

“When we discover that a variety has certain parents, what we’re saying is that the original vine grew from a seed which came from that particular cross,” explains Meredith. “Grapes are propagated by cuttings. Each grape variety has originated as a single plant that grew as a seedling, and is then perpetuated by cuttings for many, many years without changing its genetic composition.”

So now we know that the grape variety dubbed Petite Sirah by pioneer growers (probably to distinguish it from Syrah, which is similar but has larger grapes and bunches) came into being as a single seedling in France during the late 19th century and all the Petite Sirah that now exists was propagated by cuttings and buds from that original cross between Syrah and Peloursin.

(Incidentally, we now have similar insight into the origins of Cabernet Sauvignon, which is a cross between Cabernet Franc and Sauvignon Blanc--i.e., all the Cabernet Sauvignon in the world derives from the one original vine that came out of one random, exalted pollination event in the Bordeaux region.)

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But who first planted Durif here and where they planted it are still unclear. We know that Petite Sirah vineyards throughout California made such good wine year after year that they were cultivated continuously while other vineyards were torn out to make room for the crop of the moment, such as the prune orchards that filled Napa Valley during World War II.

Ridge Vineyards, best known for the old-vine Zinfandels it has produced since the late 1960s, has also bottled single-vineyard Petite Sirah for more than two decades.

Ridge president and wine master Paul Draper points out, “The old vines that have survived through Prohibition and the Depression have done so because they’re growing on excellent sites and produce particularly interesting wine. That’s why they have the reputation--not because they’re old, but because they were planted in the right place.”

When growers wanted to plant new Petite Sirah vineyards, they sought out budwood from the original plantings, thus preserving both the genetic essence and the clonal diversity of the variety. That’s important, because vines of a single variety, like identical twins, can express different characteristics in response to the soil and climate in different vineyard sites. That accounts in large part for subtle differences in wines from different vineyards.

New vines propagated from old vineyards will transmit the specific character of their predecessors, but because each vineyard is a complicated genetic puzzle, there is a danger that the complete personality of a unique old vineyard can be lost through the imprecise nature of propagation by selection.

For example, Stags’ Leap Winery in southeast Napa Valley has 22 acres of Petite Sirah. Five acres were planted in the 1930s, using cuttings from even older vineyards. The remaining 17 acres were planted in the 1990s, using cuttings from the original five acres.

Was the genetic puzzle transferred intact, or are some pieces missing? Stags’ Leap enologist Jeanette Padilla is currently trying to answer that question through DNA analysis of the old Stags’ Leap vines. The object, she says, is to identify what’s there so the old planting can be expanded without losing important components of its unique nature, as expressed in the distinctive Stags’ Leap wines.

The revelations about Petite Sirah’s identity are well timed. Zinfandel has gotten more attention in the modern wine renaissance dating from the 1970s, in large part because until recently Petite Sirah wine tended to be dense, tannic stuff that took years of aging to reveal all its delicious beauty.

But a kinder, gentler style of Petite Sirah has been winning new fans in recent vintages. Prominent wine producers such as Rosenblum, Ravenswood, Stags’ Leap, Turley, Foppiano, McDowell Valley and Ridge have cracked its code of accessibility and tamed those awful tannins. The new Petites are velvety, luscious wines that age well but are also drinkable at an early age.

Look especially for single-vineyard bottlings from the historical wine country north of San Francisco and in the Sierra Nevada foothills. Prices for these beauties are edging above $20 these days, but a fine Petite Sirah is still cheaper than a mediocre Burgundy or Bordeaux.

I’ve particularly enjoyed the 1996 Rosenblum from the Napa Valley’s Keneflick Ranch vineyard. Its charms are very similar to those of a fine Zinfandel, but in a lower register--a baritone to Zin’s tenor. The deep, rich perfume rises from the glass with suggestions of sun-warmed berries and dried roses, delicately spiced; the wine is at once firm and luscious on the palate and the finish glows like a wine country sunset.

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Meredith had previously solved the mystery of Zinfandel--well, half of it, anyway--by determining that it is genetically identical to the Italian red wine grape called Primitivo. However, since Zinfandel was being grown in California well before Primitivo appeared in Italy, the question of the grape’s origin is still open.

Just months ago Meredith’s DNA analysis ruled out the best candidate for a Zinfandel/Primitivo antecedent, a grape called Mali Plavac, which is widely grown in Croatia. So Zinfandel’s ultimate origin is still a mystery.

Scientists will doubtless pursue the question as long as there’s hope of a meaningful conclusion. We happy wine lovers, however, don’t need to bother our little heads about it. Under the time-honored “finders, keepers” rule--as applicable to viticulture as anything else--both Petite Sirah and Zinfandel belong to California.

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Smith is a freelance writer living in Northern California.