Taste and Terroir in the Napa Valley

By Jonathan Swinchatt and David G. Howell
June 29, 2006

Discussion of terroir in Napa today, and California as a whole, eventually settles on the impact of the ultra-ripe, ultra-rich, hedonistic style of wine that has become the most hotly debated aspect of winemaking in the state. The style is surely Californian-big, warm, exuberant, intoxicating, excessive and, some might say, a bit superficial. But let's face it-for most of us the first taste of this stuff is fabulous. Soft fruit and sweet alcohol fire up pleasure centers in the brain, no interruption from edgy tannins or acids that bring pause and attention to what's happening to your taste buds, just pure, mouth-filling enjoyment. For some, this is wine heaven, there's nothing better. For others, this overwhelming style quickly becomes, well, just a bit dull-they miss nuance and subtlety, qualities that, for them, transcend the seduction of pure sensual delight.

Debate about this wine style, its growing influence, its affect on the expression of terroir, and the forces that lie behind its rise to prominence, began to surface several years ago. Now the discussion has become quite public, propelled in part by the controversial documentary "Mondovino" which focuses on the so-called globalization of wine, and also by the popular film "Sideways," which has brought intense focus to Santa Barbara County and its Pinot Noir. Here, we want to explore how the notions of taste and terroir manifest in the Napa Valley, California's premiere wine region and the source of many of the wines that have fueled the controversy.

The debate is framed in various terms: New World vs. Old World; International vs. Traditional; Populist vs. Elitist. Whatever the label, the question remains-what factors underlie the rise to prominence of these wines? Is it the influence of powerful wine critics? Does it reflect the results of new viticultural and winemaking practices? Is it a factor of warming climate? Or does it reflect a response of winemakers to the American palate?

The answer, it appears to us, lies in the convergence of all these factors. Perhaps ironically, they have come together at a time when winemakers and wine drinkers in America are becoming increasingly interested in the notion of place, of provenance of wine, and more open to considering the effects of the array of influences symbolized in the word 'terroir.' In Napa, one aspect of the recognition that the land shares at least equal status with the winery is reflected by some recent vineyard studies that reveal marked connections between vineyard geology and grape quality and character. Still, many wonder if the characteristics imparted to wine by such connections with Earth-by the terroir-can survive the viticultural and winemaking practices that produce the ultraripe, opulent style that now attracts the attention of the wine-drinking world.

Our view of terroir is broad: Based in the physical characteristics of place-climate, topography, geology, soil-it includes the winegrower and the winemaker, both of who make a host of decisions that affect the character of wine. And it includes the critics as well, who now exert a powerful, unsought (though vigorously defended), influence on wine style and the way terroir is expressed. The situation is well-known: American, and other, consumers tend to buy wine based on the ratings of The Wine Advocate (Robert Parker), The Wine Spectator, and The Wine Enthusiast. The power of these ratings lies in part in their apparent objectivity-precise numbers that suggest a pure measure of quality. But it's important to recognize that these ratings are, at heart, highly subjective-just the numerical expression of the taste of a few individuals. And anyone who has experienced a blind tasting of wine knows well that taste varies extensively from one person to the next, whether they be novice wine drinkers, experienced tasters, or industry professionals.
In America, a land that prides itself on its individualism, this dependence on experts appears as a striking anomaly. Or does it? Leo McLoskey, head of Enologics, a firm that provides winemakers with advice on how to increase their wine ratings, maintains "Americans want to be told what to like." Colin McPhail, who makes gin for Leslie Rudd (of Rudd Wines), thinks that Americans are afraid of their own taste, fearful of expressing disagreement with the experts. This may well be: in a recent blind tasting for members of the Wine Club at the University of California at Berkeley, the votes for favored wine were almost evenly divided among eight Cabernet Sauvignons of various style and character from throughout Napa. In the absence of ratings, consumers' taste seems to be more diverse than that of most prominent wine critics. Why, then, can't we trust our own taste and choose for ourselves?

The way it is now, high ratings equate with increased sales and higher prices, so winemakers are understandably concerned about their numbers. Some find themselves in a classic double bind. John Caldwell worries that the wine he produces is no longer true to his terroir, a rocky hilltop in Coombsville, an area east of the City of Napa underlain by volcanic rocks. He thinks it's coming perilously close to being too alcoholic, too intense, too powerful to reflect the character of his place. Yet he feels the need for high Parker ratings to remain economically viable, so he treads the fine line between ripe and ultra-ripe, between enough and excess, trying not to sway too far one way or the other.
Rosemary Cakebread, winemaker at Spottswoode, one of Napa's consistent producers of balanced, elegant, structured, and interesting Cabernet Sauvignon, also worries that she is "pushing the envelope" of ripeness. Like Caldwell, she is trying to produce a wine true to this unique property east of St. Helena while seeking the critic ratings that she and the owner, Mary Novak, feel necessary for survival. For many winemakers who are intent on expressing terroir, it has become a tough game.

Consumer taste has been cited as a significant factor in the rise of the International style. In a recent review of "Mondovino," New York Times critic A.O. Scott (who admits to preferring beer) observes "One of the unexamined ironies of this...film is its assumption that the tastes of the imperial British aristocracy of the 19th century were not only superior to those of the 21st century American middle class but also friendlier to the enduring values of civilization. I don't know much about wine, but to me that leaves a funny aftertaste." He has a point, but for those who prefer wine to beer it's perhaps well to remember that the taste of the American middle class has been influenced for decades by sweet, rich, and not particularly subtle food and drink-think Coca-Cola, MacDonalds shakes, ice cream, candy, sugared peanut butter, and blush wines. Indeed, it might well be that the taste of previous generations in Europe (and America, for that matter), if not superior, may at least have been less narrowly conditioned than that of today's American middle class.

What about viticultural practices and the physical aspects of terroir? The majority of Napa wines are produced in the valley itself and on the hills that form its borders, the Mayacamas Mountains on the west and the Vaca Mountains on the east. The topography is rugged-faceted mountain slopes provide a broad diversity of sun aspect. The climate is Mediterranean, with rainy winters and hot, dry, summers. Hot air rising in the northern part of the valley during the day in summer draws cool air from San Pablo Bay in the south, creating a temperature gradient that, generally, increases south to north. Valley and coastal fog mitigate the temperature. The climate has always been considered nearly ideal for Cabernet Sauvignon, even though temperatures of over 40 degrees C are common in August and September. This perception might now be changing.

Most of Napa acreage has been replanted over the past 15 years-phylloxera was identified in Napa in 1983 and by the 1990s it could no longer be ignored. The cost was staggering, but it encouraged change and modernization that included new rootstocks, new clones, and new methods of trellising and pruning. The first decision-choosing the best variety for a site-seemed straightforward, based as it was on decades of experience. Chardonnay in cool Carneros and on the slopes of the hills, early-ripening Merlot on clay-rich soils in cooler locations, and Cabernet Sauvignon, the variety on which Napa's reputation depends, almost anywhere north of Yountville and in warmer locations to the south. In part, this reflected a conventional climatic wisdom that had not been questioned for decades because it seemed to provide adequate guidance.

That climatic wisdom was based on temperature data compiled and organized by Albert Winkler and Maynard Amerine of the University of California at Davis who classified California agricultural land into 5 Viticultural Regions based on heat summation measured in degree days. In the late 1990s, David Jones of Lava Cap Winery reviewed this classification and suggested that it might no longer be accurate for the Napa Valley, which perhaps had become warmer over the decades since the publication of Winkler's textbook in 1962. Indeed, Gregory Jones of Southern Oregon University recently has reported a persistent warming trend in California's North Coastal Region, which includes Napa, of almost 0.9 degrees C over the past 50 years. He states that this has manifested as a warmer growing season with higher minimum temperatures, fewer frost days, earlier last frost in Spring and later first frost in Fall (68 additional frost-free days). These observations shine an objective light on the concerns of some winemakers. Christian Moueix of Dominus (and Petrus), for example, says that were he to buy more land it would be in the cooler regions south of Yountville where his present vineyards are located. And Yountville is in the southern, cooler, end of the Napa Valley. Some think that Carneros, the coolest region in the Napa Valley AVA (American Viticultural Area, a designation based on history, geography, geology, and politics), is now too warm for Pinot Noir. These climatic considerations are closely linked to new approaches to trellising and pruning.

Concern for the vineyard evolved only slowly, having to overcome a strong belief that great wine is made by great winemakers. In the 1970s, the winemakers sought power and intensity, but the result was wines that too often were harshly tannic and over-oaked. (Remember, the modern California wine industry dates back only to the 1950s, a time, after Prohibiton, the Depression, and World War II, when only a handful of experienced winemakers remained). The solution in the 1980s was a concern for 'balance and harmony,' but the results were elusive and the wines often thin and unpalatable. It finally dawned in the 1990s that wines are made not in the winery but in the vineyard, that balanced wines come from balanced vines, not necessarily from the magic of the winemaker. As wine educator Karen MacNeil has observed, makers of great wine "witness" the process rather than attempt to control and dominate it. Serendipitously, this recognition in Napa coincided with the need to replant.

Twenty years ago, vines in Napa were planted 8 feet apart in rows spaced at 12 feet (English units by convention).  The vines grew freely in the 'California Sprawl,' producing a multitude of long canes that carried too many leaves to feed too little fruit. Grapes, shaded by abundant vegetation, ripened slowly and tended to develop harsh tannins and excessively herbaceous flavors. Today, most vineyards in Napa are planted at 5x7, 6x6 or even 3x4 feet. Most are vertically trellised, some with split canopies to compensate for vigorous soils. The goal is a balanced vine with 15 or 16 leaves supporting two clusters per cane and a metabolism that, at veraison, shifts plant energy from growing shoots to ripening grapes. Ripening, now thought of as physiologic maturity rather than simply degrees Brix, is enhanced by exposing the fruit to the sun through trellising, pruning and, if necessary, dropping leaves. There is little doubt that these new methods have produced better grapes. Yet the combination of exposing fruit to the sun, higher temperatures, a longer growing season, dropping fruit to increase intensity, and concern for favorable recognition by critics, forces the grower each year into a zone of considerable risk.

The challenge in Napa is to attain physiologic maturity-ripeness of tannins and seeds as well as sufficient Brix-without losing acid or ending up with high sugar and excessive alcohol, taken by many as greater than 14 or 14.5 percent. Years ago, Michel Rolland, proponent of low yields and long hang time, told Napa winemaker John Kongsgaard that in California the sun is the enemy, it makes the grapes ripe too early. He maintained that too short a time from veraison to harvest produces poor wines. Now it's getting progressively warmer and long hang time takes the grapes into a zone that risks loss of acid and the structural balance it provides. Ric Forman observes you can get the required mature flavors that develop with long hang time at relatively low sugars in France but that similar development in California is accompanied by "high sugars, ultraripe grapes with pH greater than 4, and huge alcohol, so high you have to add water to the fruit." The tradeoff, then, for mature flavors seems to be high alcohol, low acid wines that are mouth-filling on first taste but which for some wine drinkers quickly pall. And no one really knows how these wines will fare with age.

This is not the case everywhere in Napa. Some sites, commonly in the hills, achieve vine balance quite naturally, with comparatively little effort on the part of the grower and with less risk of excessive ripeness. We think this is in part a factor of geologic conditions.

Bedrock in Napa is diverse. Volcanic rocks underlie the ridges and hills that frame the east side Napa Valley, commonly known as the Vaca Mountains. Volcanics also lie at the surface in the northern third of the Mayacamas Mountains on the west and in a thin band along the western edge of the valley. The Franciscan mélange, a peculiar mix of ocean floor sediments and chunks of ocean crust, lies at the surface in the middle part of the Mayacamas and in isolated patches throughout the Vaca Mountains. Sandstones and shales of the Great Valley sequence occur in the southern part of the Mayacamacas and in the eastern ranges of the Napa Valley AVA. The valley itself is filled with relatively youthful sediments that have accumulated over the past 15,000 years. Most of the vineyard substrate in Napa is so young that strong soil profiles have not had the opportunity to develop. As a result, geologic factors appear to exert more influence on grape quality and character than does soil type.

Bedrock is an important part of the geologic story, but the loose material that lies on top-the realm of vine roots-is the action zone of terroir. Produced by the weathering and breakdown of bedrock, this loose sediment either accumulates in place or is moved down slope by water and gravity during major storms. As the streams rage out of the mountains, flow velocity drops abruptly at the edge of the valley; boulders, cobbles and gravel are dumped quickly while finer sediments move progressively farther away from the hills. Over time, a fan-shaped body of sediment, much like a river delta, forms at the edge of the valley. These deposits are known as alluvial fans. Down slope, beyond the fans, the finest sediment is carried onto the flood plain of the Napa River, which transports and mixes debris from all areas upstream. Rich in nutrients, with abundant clay minerals that store water in their crystal structure, these fluvial (river) deposits are the most vigorous of Napa sediments and the most challenging for the production of quality grapes. The character and distribution of these three kinds of sediments-residual, alluvial, and fluvial-is key to understanding Napa terroir.

Residual sediments occur as thin veneers in the hills, often less than 40 centimeters thick. Covering the slopes and hills of Napa, they lie at higher elevations where cooler temperatures favor natural balance in the vines. Rich in boulders, cobbles and gravel, well drained, and poor in nutrients, residual sediments provide a stressful environment for vines that produce low yields of particularly intense, small-berried, fruit. Historically, residual sediments have produced wines of significant power, with strong tannins balancing intense fruit. The wines age well, often needing a few years to soften and integrate. Dunn (Howell Mountain), Diamond Creek, Harlan, Mayacamas, Burgess, Dalla Valle, and Joseph Phelps (Backus Vineyard) are long time producers of wine from grapes grown on residual deposits. Marston Family, Constant, Longmeadow Ranch, Barnett, and von Strasser are among the newer additions.    

Alluvial fans occur along the edges of the valley; on the west side they form a nearly continuous band south of St. Helena. Fan sediments are a mix of boulders, gravel, sand, silt, and clay. Coarser sediments lie near the mountains and extend down the fan in thin, irregular lenses that mark the paths of older stream channels. The internal architecture is complex, marked by intricate inter-layering of coarse and fine sediments; on the outer edges, fan sediments mingle with those of the river flood plain. The effects on viticulture are unpredictable: alluvial fan sediments can be well to poorly drained and exhibit low to high vigor. Yields vary; growers often drop fruit to increase intensity. Wines tend to show berry fruit flavors with supple tannins and good concentration; those from the eastern fans, exposed to the intense afternoon sun, are perhaps a bit more edgy. Wines from west side fans include Spottswoode, Beaulieu Vineyards George de la Tour, Opus, Dominus, Staglin, Far Niente, Paradigm, and Mondavi Reserve; from the east, Araujo Eisele Vineyard, Stag's Leap Wine Cellars (Fay, SLV, and Cask 23), and Clos du Val to name just a few.

Fluvial sediments on the flood plain are fine-grained, poorly drained, and the most vigorous of Napa substrate-growing great wine grapes under these conditions is a serious challenge. We know of no high quality wine in Napa that comes entirely from grapes grown on flood plain.

Previously, discussion of Napa terroir took place within either the simple context of mountain vineyards versus those on the valley floor or in relation to the 14 designated AVAs. A number of the AVAs, however, run from one side of the valley to the other and contain several geographically and geologically distinct terroir. To speak of Oakville or Rutherford terroir, for example, means little-both AVAs stretch from the base of the Mayacamas Mountains to the base of the Vacas and contain volcanic and sedimentary bedrock, different types of sediment, and both east- and west-facing mountain slopes. Residual, alluvial, and fluvial sediments, on the other hand, are geologically distinct and their distribution can be mapped. Geographic location tells something about climate: Cooler in the south and at higher elevation, warmer in the north and lower elevation; more rainfall in the hills than on the valley floor. Sun aspect depends on the site. Taken together, sediment character and geographic location begin to distinguish one terroir from another.

But these factors provide only an overview of terroir, a notion that is sensitive to scale; every vineyard we have examined in detail is significantly different from its cousins, even within the same broad sediment category or geographic location. And in some we have established a direct correlation between geology and grape character as defined by a winemaker's taste buds.

At Stag's Leap Wine Cellars, a small alluvial fan is made up, in part, of the remains of two debris flows. These are coarse deposits-mainly boulders, cobbles, and gravel-that roared out of the mountains as thick slurries that came to rest quickly as a chaotic mix of particles, with the finer material winnowed out and carried farther into the valley. In one block, winemaker Michael Silacci, now at Opus One, picked selectively from what he called the 'Hershey Kiss,' an area shaped like a piece of that candy tipped on its side, a rounded pyramid with a sharp tip. Later, we found that this area coincided almost precisely with a part of a debris flow that we could map on the basis of its geologic characteristics. We have found similar relationships at Araujo Estate, where vines have been planted and grapes picked in patterns that, on hindsight, reflect closely the underlying geology. It appears that the geology of vineyard substrate is indeed linked to grape character.

What does this tell us about terroir in Napa? Winegrowers and winemakers in Napa generally agree that the primary control on grape quality and character (assuming equitable climate) is drainage and the way that water is made accessible to vine roots. These factors reflect the imprint of geological processes on vineyard sediments. In very broad terms, the best grapes in Napa come from sites with coarse, well-drained sediments, whether they are in the mountains or on the edge of the valley. Better drainage creates a more stressful environment for the vine, which produces grapes with greater concentration and wines of more depth and power. Finer-grained vineyard sediments, particularly if they contain layers or admixtures of clay, tend to produce more elegant, silkier wines, while requiring greater viticultural attention that sometimes involves the installation of subsurface drainage.

Site-specific weather (day to day variation) surely adds to the unique nature of a location, but its specific contribution is difficult to determine. Australian wine researcher John Gladstones has suggested that the best sites, around the world, are those with the least day-to-day and day-to-night temperature variation during ripening, but information that correlates specific site attributes with particular wine characteristics (such as aromas and flavors) is not at hand.  The scientific experiments needed to clarify these relationships are complex and expensive-they are unlikely to be undertaken any time soon. Perhaps this is all to the good; the mysterious and beguiling aspects of wine have always been part of its allure. And now, recent developments in Napa will surely add to the mystery and perhaps move attention in a new direction.

Biodynamics-the esoteric approach to agriculture devised by mystic/scientist/ philosopher Rudolph Steiner and grounded in the peasant agriculture of 19th century Eastern Europe-has come to Napa. A number of vineyards have been using organic approaches for some time-Spottswoode, Araujo Estate, Volcker Eisele, and Grace Family among them. Now, some of these, and others, have moved on to biodynamics. The esoteric side of the approach tends to get the dramatic press: After all, who would have thought the rational minds of successful businessmen and entrepreneurs would ever succumb to the notion of 'energizing' compost with manure stuffed into cow horns and buried for a very specific time? Or improving vines by spraying leaves with ground silica stirred into water in a precise, vortex-creating pattern for 60 minutes? Or even planting, irrigating, and fertilizing by the phases of the moon? And yet they have, prominent winery owners and winemakers such as Bart and Daphne Araujo, Agustin and Valeria Huneeus (Quintessa), Craig Williams (Joseph Phelps), and John Caldwell (once a supplier of rootstock and clones) among them. What's more, all are enthusiastic and have persuasive, if anecdotal, evidence to support their determination to follow what is an intricate and challenging approach.

What's most interesting about biodynamics, however, is not its esoteric components but its focus on the land. Ideally, all the materials used-including cow horns, manure, and compost materials-should come from the site that is being treated.

In a place like Napa, where vineyard land runs several hundred thousand dollars an acre, that's not likely to happen. But perhaps more importantly, the application of biodynamics forces you to look closely at the land and everything you do, bringing a fresh perspective and intense attention to well-established routines. The land becomes primary, with great grapes coming from ground that is approached with thoughtfulness, good intent, and, yes, a spiritual quality that arises from reaching deeply into personal beliefs about mind and matter. Could there be any better approach for those who seek to make wine that reflects the place in which it grows and want to maintain the land for future generations of winemakers?

In the long run, bioodynamics is about balance, about bringing integrity back to land that has been overworked, over-fertilized, and perhaps even over-cropped. It will be interesting to see how it works in Napa, a place of contentious debate between environmentalists and winegrowers about how best to move into the future. The advent  of organic and biodynamic farming and their focus on sustainability might bring some needed balance to the controversy, but that outcome is not inevitable. California is not inherently a place of balance; rather, it's a place of innovation and change, influenced by immigrants from around the world, shaken periodically by earthquakes, and subject to a boom and bust economy that so far has managed to recover from every setback. It's a place of optimistic over-exuberance and of eager grasping for the new based on the outlook that if enough is a feast, more will surely be a banquet. And it's a place with great faith in technology. Even today, when adjustments to viticultural practice might lower the risk of high sugar and high alcohol, some in Napa are relying on spinning cones and reverse osmosis to reduce alcohol to more acceptable levels.

Micro-oxygenation, used to rapid-age and soften tannins, is becoming more common. We have heard reports that these processes do not damage the wine, but they are remedial techniques that attempt to produce balance where it does not exist, treating a symptom rather than the disease.

We wonder a bit about the future course of wine in Napa and California, particularly if predictions of additional temperature increases of over a degree C by 2050 prove correct. Will ever-new technology appear to patch the system enough to allow Napa to rely on varieties that might, in the not too distant future, be considerably less viable than they are today? Will Napa winegrowers experiment with crop management to see if it can bring sugar ripening and maturity of seed, skin, and tannin into better balance? Can they find ways to develop mature flavors earlier in the season?  Whatever course Napa winemakers take, it's likely to be as exciting, unpredictable, enterprising, and unbalanced as it has been in the past. It's the California way, and we intend to hang on for the ride.

Acknowledgement

This article originally appeared in Issue 7 of The World of Fine Wine magazine. The article may not be sold, altered in any way, or circulated without this statement. Every issue of The World of Fine Wine features coverage of the world's finest wines in their historical and cultural context, along with news, reviews, interviews and comprehensive international auction results. For further information, and to subscribe to The World of Fine Wine, please visit www.finewinemag.com or call +44 (0)20 8950 9177. 

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