As I signed books – have I told you about my book? – at Cooper Vineyards in Amador County’s Shenandoah Valley earlier this winter, one considerate member or another of the tasting-room staff would bring me a glass of wine.

Before the day was over, I’d tasted a Marsanne of uncommon crackle and complexity, an exquisitely layered Sangiovese, and an exceptionally bold Barbera.

All fine wines, but the one that remains stuck most firmly in my memory bank is the Cooper Vineyards 2019 Amador County Shenandoah Valley St. Peter’s Church Zinfandel ($41).

OK, Zinfandels are available all over Shenandoah Valley, and throughout the Sierra Foothills, for that matter. But this one stands our for the unusual lyricism with which it represents place and variety. Zinfandels coming out of Shenandoah Valley typically are big and brash, their fruit so ripe they can cross over from the lift of berries to a sucker punch of prune, even the dried concentration of raisins. They can be balanced and captivating, and unlike Zinfandel from any other appellation in the state.

But the Cooper St. Peter’s Church Zinfandel stood apart for its sunny berry fruit, peppy acidity, silky tannins and exquisite nuance. It was fresh and spicy, its spice dashing from clove to pepper.

I’d been unaware that Cooper Vineyards had been releasing a St. Peter’s Church Zinfandel since the 2012 vintage, though aware of St. Peter’s Church Zinfandels from other wineries, most notably Rosenblum Cellars.

Almost coincidental with my introduction to the Cooper St. Peter’s Church Zinfandel, wine writer Jess Lander of the San Francisco Chronicle dove into the history of the five-acre 130-year-old vineyard behind St. Peter Roman Catholic Church of Cloverdale in northern Sonoma County.

The early history of the vineyard is murky. Not until the 1990s did anyone pay it much attention. Then a parishioner, Jack Florence Jr., a nascent vineyard manager, took over farming of the vines, notes Lander. In 1994 Florence began to sell grapes from the plot to Kent Rosenblum of Rosenblum Cellars at Alameda, which since the winery’s founding in 1978 had been drawing attention for monumental Zinfandels.

Rosenblum subsequently released a St. Peter’s Church Vineyard Zinfandel, while Florence used cuttings from St. Peter’s to graft vines in rugged terrain just northwest of Dry Creek Valley, overlooking Lake Sonoma. In 2002, that area formally was recognized by federal authorities as the Rockpile American Viticultural Area.

Four years later, Dick Cooper, fretting over both a drop in price for Amador County Zinfandel and intensifying competition among Shenandoah Valley’s Zinfandel producers, calculated that he needed to somehow set himself apart from the rest of the pack, recalls his winemaker, Mike Roser.

Cooper was aware of the quality of Zinfandel coming from St. Peter’s Church Vineyard, acquired cuttings, and planted on his Shenandoah Valley ranch 2.8 acres of the strain. “He had a feeling it would be different, it was so distinct, and there was the story behind it,” says Roser.

As Lander notes in the Chronicle feature, St. Peter’s Church Zinfandels commonly are described as “dense,” “concentrated,” “dark” and “intense,” descriptors that also apply to Zinfandels traditionally emerging from Shenandoah Valley.

There, however, the St. Peter’s Church clone, as exploited by Cooper Vineyards, is yielding a far different wine – lighter in color than the norm, sleeker in structure, sharper in acidity, and more suggestive of strawberries and raspberries than the boysenberries, prunes and plums frequently suggested by Shenandoah Valley Zinfandel.

“It’s a little lighter in color (than other Zinfandels), and that surprises people, all that flavor despite the light color,” says Roser, who has been Cooper’s winemaker since the winery was established in 2004. (Dick Cooper died in 2021, but the winery remains in the hands of his four daughters.)

At first, Cooper and Roser blended fruit from their block of St. Peter’s Church Vineyard cuttings with other lots of Zinfandel, but soon they recognized how different the St. Peter’s wine was from the others, so with the 2012 vintage they began to bottle it as a vineyard-designated release.

In the cellar, Roser ages around a third of the wine in new American-oak barrels for 36 months compared with 24 months for his other Zinfandels. He makes 350 to 450 cases each year, and the winery has no problem selling out quickly, he says. Despite that, the family has no plans to expand its plot of St. Peter’s Church Zinfandel.

Why the St. Peter’s Church clone expresses itself as it does in Shenandoah Valley is open to speculation. The Shenandoah Valley soil, exposure, temperatures and so forth all vary from the settings in which the grape is planted in Sonoma County. What’s more, clones are ever mutating. At Cooper, the strain customarily ripens a bit earlier than other strains of Zinfandel, notes Roser. (The Zinfandel planted most extensively in Shenandoah Valley commonly is called the Deaver clone, in recognition of one of the older and more impactful vineyards in the area.)

Wine enthusiasts who have designated Cooper Vineyards as one of their destinations during Amador County’s “Behind the Cellar Door” tours the weekend of March 25/26 are in for a treat. There, Roser will oversee a vertical tasting of St. Peter’s Church Vineyard Zinfandels from the 2017 through 2019 vintages, as well as offer barrel samples of the 2020.

About that book I mentioned high up – “The Signature Wines of Superior California: 50 Wines that Define the Sierra Foothills, the Delta, Yolo and Lodi” – the St. Peter’s Zinfandel isn’t one of the highlighted wines, though the Cooper Vineyards Amador County Shenandoah Valley Estate Vineyard Barbera is. If a future edition is published, however, the St. Peter’s very likely could break into the lineup.

To learn where “The Signature Wines of Superior California” can be found, please visit my website SignatureWines.us. An electronic version now is available at Amazon.com.