Wine & Spirits - December 2019 - 33

Why is this? One of a grapevine's most compelling features is its potential longevity: The thick, gnarled trunks of ancient vines speak of virtual
immortality, outliving multiple human generations (indeed, like trees).
In the zinfandel world, these indomitable elders command reverence as
historical artifacts and exemplars of terroir. Why don't Napa Valley cabernet growers pay them the same respect?
The answers are multifarious, touching on history, biology, and-especially in Napa Valley-economy.
Like the sprawLing bush vines themseLves, all of the above
forces are intertwined. They certainly converged in the phylloxera epidemic that wiped out vineyards in California and Europe in the late nineteenth century and again, in California, in the late twentieth. After the first
disaster, most vineyards were replanted on native American rootstock,
which is resistant to the phylloxera louse. In Napa Valley, the choice was
usually Rupestris St. George and, later, AXR-1, which encouraged more

74-YEAR-OLD BUSH
VINES (RIGHT) ALONGSIDE A MORE RECENTLY
PLANTED VSP BLOCK
AT SCARECROW.

generous yields. Though initially thought immune, in the 1980s AXR-1
was exposed as vulnerable, necessitating another (expensive) round of
replanting.
That would be one reason for a scarcity of old cabernet vineyards. But
what about those planted on St. George? Weren't they as worthy of preservation as zinfandel? Not in the eyes of Joel Peterson, founder of Ravenswood and a notable champion of (1) old vines and (2) zinfandel.
"Cabernet was kind of a misfit for early California," he says. "St. George
is super-vigorous and so is cabernet, so the rootstock didn't work to the
variety's strengths-the clusters shattered a lot, and there weren't a lot
of berries. [Back then] people were looking for a reliable cropping grape,
but cabernet was a shy bearer-and as it gets older it's even more shy
bearing, whereas zinfandel is a big producer early and balanced later on.
It's also more disease-resistant."
That was another strike against cabernet seniority: susceptibility to
Eutypa, a fungal disease that kills vines. "Wood-rotting diseases exist to
make sure there's room for everything else on the planet," muses Dr. Andy
Walker, a geneticist and rootstock breeder at U.C. Davis's Department of
Viticulture and Enology. "Cabernet is pretty susceptible to them, both
directly and indirectly. When we've taken out older collections [of plant
material at Davis], more frequently there are dead vines in petite sirah,
chenin blanc and cabernet sauvignon."
That would be "direct" vulnerability; as for the indirect kind, Walker
says, "Since cabernet is a vigorous variety, it gets many larger [pruning]
cuts into the older structure of the vine. That allows diseases to get in."
Finally, there's the scourge of aging vineyards everywhere: viruses like
leaf roll, fan leaf and red blotch, which reduce the plant's ability to photosynthesize and thus, inhibit ripening. There's perennial debate on this
issue-not just whether cabernet is especially sensitive to viruses, but
about the extent to which they impair wine quality.
"There's a long contention in Europe that virused vines will make better
wine," Walker says. "I would say can, but not will. Most viruses, without
question, impact vigor, reduce yields, reduce sugar levels, reduce color
and reduce quality. Some effects are very negative and some are less damaging, but usually they don't occur all by themselves-vineyards will have
a mix of multiple viruses."
In any case, insecurity about viruses is another reason for vines to be
replanted. "The [contemporary] philosophy," according to Graeme MacDonald's brother Alex, "says that any time you see a vine that has a disease, you pull it out so it doesn't spread."
"Twenty years ago, Napa Valley was brilliant bright red in autumn,"
recalls Mark de Vere, a Master of Wine who works for the Robert Mondavi
Winery. "We don't see that any more-it's been replaced by non-virusinfected vines. Healthy vine leaves are not red but green, then yellow and
orange after harvest. Those are the natural colors of senescence."
The subject might have heightened sensitivity at Mondavi because of
the To Kalon vineyard, which of late has been notoriously afflicted. Mondavi's portion contains the oldest cabernet vines in To Kalon-the socalled monastery block, planted in 1945 next to a Carmelite mission at
the western edge of the property."It's riddled with virus-and very unreliable," de Vere reports. "In some years when the virus is not expressing
itself, it gives magnificent fruit, but it's not consistent or complete enough
to justify a wine made just from those vines. It's only been a component of
another wine-sometimes the Reserve, sometimes Oakville." As a result,
"I'm afraid that that block will have to be pulled within a year or two.
"I'm a big fan of old vines, so I'm sorry to see them go," de Vere demurs.
"But it's hard to argue with a person whose job is based on running a
healthy vineyard. The old-vine zinfandel story is hugely meaningful to
the industry, but zinfandel ripens a lot earlier than cabernet, before the
slowing down due to virus becomes an issue. Since [old zinfandel vines]
are less susceptible to disease and infection, they still have viable yields,
whereas old cabernet vines don't offer the same upside advantage.
WINE & SPIRITS

DECEMBER 2019

Wine & Spirits - December 2019

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