When asked about the tricks of their trade, most Santa Barbara County winemakers quickly declare that wine is made in the vineyard. They admit the impossibility of crafting great wine from mediocre grapes and generally spend as much time prowling among the vines as they do working in the cellar.
The soil, a living medium of minerals and organic material, supports the vines and constitutes the backbone of any vineyard. Created over millions of years, it is the byproduct of receding seas, river-deposited particles, and the slow weathering of ancient parent material, which in Santa Barbara County includes shale, serpentine, and sandstone.
Regional soils range from sandy loam in the west to cobble-studded loam in the east to alluvial sand and clay intermingled with shale in the north. Although such vineyard conditions as climate, water, and exposure contribute to the terroir—an elusive French term referring to the expression of environmental factors in a wine—it is the soil that supports the vines and fuels the conversion of sunshine into sugar.
In the Santa Maria Valley, vineyards grow on elevated plateaus and along benches above the Santa Maria River. Mostly of marine origin, the well-drained sandy and clay loams include a measure of sedimentation from river wash.
“In my opinion, the big story in Santa Maria Valley is the soils,” said James Ontiveros, a winegrower who owns Rancho Ontiveros Vineyard. “They are much more dramatic than the weather, which is pretty consistent from one end to the other, though it does get warmer when you go west to east.
“North of the Santa Maria River,” he continued, “you’ve got the San Rafael mountain range that provided that big alluvial fan most people think of when they think of the Santa Maria Valley. But on the valley floor and further south and west up into those marine terraces, the soil is silty and sandy, sediments left behind from the last time the ocean withdrew.”
Ontiveros planted his vineyard in that silt, on a ridge overlooking the surrounding farmland. He explained that silty soils tend to warm up and dry out quickly, which can cause grape stems to become more woody, thus improving the flavor of the vine’s fruit.
According to Bryan Babcock, co-owner and winemaker at Babcock Winery, the secret to vinicultural success is to match the appropriate grape variety to the vineyard soil.
“It’s because of the nature of the geology, the actual content of the soil,” Babcock said.” I think it does influence the flavor, like any terroir. It is what it is, and the wine is what it is as a reflection of that soil.”
Babcock has farmed grapes in the cool Santa Rita Hills west of Buellton since 1984. He christened a number of his vineyard blocks with names chosen to reflect their origins, such as Ocean’s Ghost, which once lay at the bottom of the Pacific Ocean, and Top Cream, a moniker that describes the vineyard’s upper layer of grayish-white sandy loam.
Lean and low in fertility, the soil of Top Cream inhibits the vigor of the Chardonnay vines that grow there. It has proved ideal, however, for producing stellar wine, especially when the grapes are put through traditional Burgundian winemaking techniques, including the secondary, malolactic fermentation that yields a distinctly creamy texture.
Serendipitously, the powdery diatomaceous earth (derived from prehistoric marine algae called diatoms) mined in and around Lompoc makes an effective filter for removing suspended particles from wine. Bright white in color, it’s easy to spot amid the darker soils of the Santa Rita Hills.
While the soils of the western edges of the Santa Ynez Valley are suited to Pinot Noir and Chardonnay, those in the valley center produce fine Italian and Rhône varieties. In Ballard Canyon, for example, the limestone and clay soils of Stolpman Vineyard produce outstanding Syrah, noted for its intense components of vanilla and ripe blue fruits.
Next door, the Beckmen family’s Purisima Mountain Vineyard sports similar soils atop a limestone subsoil rarely found in California, but typical of the famous Rhône region of France. It is made up of a dense layer of calcium carbonate that stymies root penetration and forces vines to get what they need from the thin topsoil.
The struggling plants yield small crops of grapes loaded with the flavors that typify the variety. The wines exhibit lush notes of plum, blackberry, and chocolate, flavors not taken directly from the soil, but rather conjured during the vine’s labor to ripen fruit, in the vineyard, where wine is made.
K. Reka Badger’s columns are all made using the best limestone and clay soils. Contact her at rekabadger@hotmail.com.
This article appears in Aug 4-11, 2011.