"When we have visitors to our winery," says Christopher Howell, winemaker and general manager at Cain Vineyard & Winery in Napa Valley, Calif., "I remind them of the most basic thing: that wine comes from grapes, that grapes grow in vineyards and that vines grow in dirt.
"Not all wines reflect the place where the grapes grow," Howell goes on, "but the more interesting wines do. We don't know completely why certain places make distinctive wines; we just know that they do. Differences in soil mean differences in flavor."
In last week's column, volcanic, alluvial and granitic soils spoke their piece about how soil affects the grapes that grow on them. This week, limestone, slate and schist have their day.
A rock or soil formed mostly from fossilized marine shells, limestone is the bedrock of some of the world's more significant wines, those for instance from Coonawarra, Australia; Tuscany, Italy; and France's Chablis, Champagne, Cote d'Or and many grand crus of the Alsace region.
Limestone is highly nutritive to vines but also accentuates certain characteristics in wine grapes, hence their wines. "Calcareous soil (another name for limestone) gives natural acidity," says Daniel Daou, who makes a number of wines in Paso Robles, Calif., under his name.
"It gives the best, the chalky tannins, to red wines," says Pedro Parra, a Chilean viticultural and terroir specialist.
Beppe Caviola, winemaker for Damilano, a Barolo producer in Piedmont, Italy, says that the limestone portion of the top-flight Cannubi vineyard contributes to its "finesse and elegance."
2010 Clos des Fous Pinot Noir "Latuffa" Traigen Vineyard Malleco Chile: From the southernmost vineyard region of Chile; very similar to a villages-level red Burgundy, all scents and savors of dark cherry, wet stone, Red Zinger tea, furry tannin and zippy acidity. $35
2008 Damilano Barolo Cannubi Piedmont Italy: Gorgeous nebbiolo, with unfolding aromas and flavors of rose petal, cocoa and dark fruit, chalky tannin and a snappy finish; sexily elegant, whispering its delights and perfume. $90
Slate (or its parent rock, shale) figures importantly in other great global wines, such as the incisive rieslings of the Mosel in Germany or as the major contributor to the ascending fame of the grenache-based reds of Priorat, Spain.
Slate clings to the precipitous slopes of the Mosel and augments that land's limited sunshine and warmth, retaining daytime heat, only to release it slowly during the evening and its setting light. In Priorat, studded with quartz, slate is called llicorella; rocky but also porous, llicorella forces its vines to search deep, down to 80 feet, for nutrients and water.
Slate also contributes its own texture in mixtures with other soil types, such as volcanic, clay or loam. Because it crumbles easily, it can provide vine root pathways through inhospitable soils. Most winemakers claim that slate contributes distinctive minerality to red wines, scents of wet black stone or moist cellar floor.
2007 Capafons-Osso Red Blend "Sirsell" Priorat Spain: A blend of mostly grenache and merlot, rendered super-rich and concentrated, but still smooth, seamless, lengthy on the palate; moderately tannic and a great buy for all that depth at this price. $25
In addition to being the most carefully pronounced term in geology, schist resembles both shale and slate in its dark hues but is harder and less prone to crumbling than either. You find it as the grounding to the great vineyards in the northern Rhone, the Argentine Andes and Portugal's Douro Valley; it's a vineyard underpinning throughout Provence, France; Germany; Spain; Tuscany; and California. It matters greatly to wine grapes in South Africa's Western Cape.
2009 Las Rocas Vinas Viejas de San Alejandro Garnacha Calatayud Spain: Beautiful garnacha character, especially perfumed; juicy, dark red fruits that both brood and lift; minerals in the finish. $15-$20
In the course of speaking about their soils with winemakers and vineyard owners for this and last week's articles, I met Pierre Seillan, who makes wine in Italy, France and California. He said, speaking in an analogy, "There are jewels in the soil, the nutrients, but they are locked inside a sort of 'safe.' To open the safe, you need a key. The key is the weather: the wind, water, sun, the elevation."
Seillan makes many wines, but he produces two 100 percent cabernet sauvignons from two vineyards that abut in Knights Valley, a mountainous site that straddles Sonoma and Napa counties. They are two distinct wines, even in the same year, because their soils are distinct and because their different temperatures "unlock" the jewels in their soils differently.
2008 Anakota Cabernet Sauvignon Helena Montana Vineyard Knights Valley California: Very rocky volcanic, dry soil; a warm site that ripens grapes into a plush, exotically perfumed cabernet. $60-$65
2008 Anakota Cabernet Sauvignon Helena Dakota Vineyard Knights Valley California: A cool site with clay-laden volcanic soils; picked later than Montana, so more depth, more punch; dense, packed, powerful, many-layered. $60-$65
If your wine store does not carry these wines, ask for one similar in style and price.
Bill St. John has been writing and teaching about wine for more than 40 years.