Several factors contribute to the quality of a grape, from its site, soil and growing climate to its vine management, crop level, rootstock and barrel aging. But winemakers are increasingly relying on modern science to enhance and manipulate their grape stock. The heightened importance of grape clones is what makes DNA a hot topic today in the wine industry.

A grape clone is defined as a genetically uniform group of plants derived originally from a single plant by asexual propagation (cuttings, grafting, etc) When grape varieties are propagated, the goal is usually to preserve the unique characteristics of the varietal, but slight genetic variations commonly occur among the many billions of cells that make up a grapevine.

“Think about apples – there are lots of different kinds of red apples, just like there are lots of different kinds of Pinot Noir, all with unique attributes,” says Seth Kunin, of Kunin Wines and Westerly Wines.

If a new vine propagated from a shoot has favorable variations, it may become a clone that is intentionally propagated to duplicate these desirable characteristics, which can include time of bud break, time of ripening, disease resistance, cluster architecture (loose versus tight), flavor profile and increased or decreased yields. When a new clone is born it is assigned a number or given a clonal designation name to distinguish it from other clones. American viticulturists are propagating clones that best suit our terroir, but the clone capital is still France, where the national repository is planted with a collection of 1,000 certified clones.

There has been a trend in recent years for Santa Barbara vintners to designate specific vineyards as the source of their grapes for special wines. Even within vineyards, some winemakers have selected certain rows as possessing characteristics so desirable that these grapes are fermented separately, such as Summerland’s T-Block. Some of these blocks are bottled and labeled as specifically coming from these rows. That practice locally seems to date back to winemaker Chris Whitcraft’s Q block designation of his Bien Nacido Pinot Noir grapes starting in 1992.

Ever since, vintners have noticed that they have a clear advantage over winemakers of yesteryear. “You couldn’t make a white or a red burgundy in California in the 1960s and ’70s because you didn't have the right clones like we have today,” says Christian Roguenant, former winemaker at Maison Deutz.

DNA manipulation also makes it possible for burgeoning grape growers to have a place in the industry without necessarily owning an old vineyard. “Clones make a huge difference, especially in vineyards younger than twenty-five to thirty years,” says Benjamin Silver, a winemaker who is very selective about the grape clones he purchases for Silver Wines. “Some say that clones matter less when the vineyard gets older, but I pick the vineyards that I work with each year by the suitability of their location for the varietal and by the clones.”

In doing so, Silver not only gets the quality attributes he’s looking for, but he can also create the overall taste of the wine he prefers. For his Viognier, for example, Silver selects “R” clone grapes from Vogelzang Vineyard to get a more complete wine, with peach, apricot and mineral notes.

Kathy Joseph, head fiddle of Fiddlehead Cellars, gives special treatment to her Pinot Noir clones, sometimes fermenting individual clones separately to evaluate the purity of the clone, and keeping these clonal distinctive wines separate until she blends the wine. “Success with Pinot Noir is all about layers on the palate and layers of aromatics,” Joseph says. “First you need ripe fruit; a variety of clones planted in the vineyard allows the winemaker to capture the ideal ‘window of ripeness’ within the restraints of vintage variation (Fiddlestix has 32 unique blocks of six clones on three rootstock combinations). Secondly, a clonal mix offers diversity of character: some spicy, some fruity, some voluptuous, some with bolder structure. For me, it is the marriage of clones that makes our wines sexy. I would never want to declare one clone the best, as it is truly a moving target.”

Craig Jaffurs, owner and winemaker of Jaffurs Cellars, uses clones to peak advantage with his 2003 Syrah “Melville Vineyard.” He blends a Shiraz Clone 1, Estrella Clone and Tablas Creek, Clone 99, to make his limited bottling. “The Clone 1 element of this wine adds tannin and a firm yet fruitful texture,” Jaffurs says. “Clone 99 fruit adds blackness to the wine, and an element of spice and raspberry flavors. The Estrella Clone adds a rich, cherry-spice flavors and extra depth. Together they yield a wine of power, balance, and complexity that is chewy, dark, and elegant.”

Some varietal clones, such as those for Chardonnay, are not as site-sensitive as Syrah and Pinot Noir clones, and experimentation and time are needed to match terroir to clone. Richard Harris’s Calzada Ridge Vineyard, with its 612 Viognier plants, may be the smallest premier vineyard in the Valley, but that didn’t stop Harris from getting the top rootstock and clones. He says he got it right the first time with the SV1 clone on S04 rootstock, which proved perfect for his rocky soil and slightly terraced terrain.

But others don’t see cloning as a miracle cure. If grapes don’t carry essentially healthy characteristics, some winemakers say they are doomed not to reach optimal quality. “In my opinion clones are not fundamental in the growing of a great wine,” says Bryan Babcock, of Babcock Winery. “While they can be important, they are not as important as the relationship between the grape variety and the soil and climate. For example, if you are in the right place for Pinot Noir, chances are there are a number of clones that will do well. While you may have some favorites, if you are in the heart of the Santa Rita Hills, most clones of Pinot Noir should make good to extremely good wine. If you are in a really bad place for Pinot, then there is no magic clone that is going to miraculously make great wine.”

Still, winemakers don’t deny that cloning allows them to capitalize on their infinite imaginations. “Pinot Noir clones are like the paints on a palette, or, more specifically for me, the spices I use as a chef,” says Frank Ostini, owner of Hitching Post and partner in Hartley-Ostini wines. “I like combining them into blends that make a more complete and balanced wine. I try to get as many clones as I can in each vineyard wine or appellation blend.”