viernes, 6 de marzo de 2015

Terroir Definition and the Environmental Conditions of Wine and Vineyards



TERROIR DEFINITION AND THE ENVIRONMENTAL CONDITIONS OF WINE AND VINEYARDS

Source: Professional Wine Dictionary (Ernesto Serdio)

Terroir. French term employed in viticulture to designate vineyards (vine plots) or small sites or areas under vine which have homogeneous and measurable edaphologic, climatic (including sunlight exposure), hydrologic and topographic particularities. In theory, these particularities, in which soil composition plays a predominant role, are expressed over time in the quality wines coming from the areas or vine plots defined and have been the cornerstone for the determination and regulation of the cru/growth wines, especially in France (e.g. Bordeaux, Burgundy or Champagne).

When tasting wine, it refers to the wine´s tipicity, which either relates to its origin, vineyard or cru/growth. "A wine perfectly freflecting the terroir".

Source: The Oxford Companion to Wine (Jancis Robinson)

Terroir, much-discussed term for the total natural environment of any viticultural site. No precise English equivalent exists for this quintessentially French term and concept. Dubos and Laville describe it fully, and how it underlies and defines the French Appellation Controlee system. A definition is given in van Leeuwen et al. Discussion of terroir is central to philosophical and commercial differences between Old World and New WOrld approaches to wine.

Major components of terroir are soil (as the word suggests) and local topography, together with their interactions with each other and with macroclimate to determine mesoclimate and vine microclimate. The holistic combination of all these is held to give each site its own unique terroir, which is reflected in its wines more or less consistently from year to year, to some degree regardless of variations in methods of viticulture and wine-maiking. Thus every small plot, and in generic terms every larger area, and ultimately region, may have distinctive wine-style characteristics which cannot be precisely replicated elsewhere. The extent to which terroir effects are unique is, however, debatable, and of course commercially important, which makes the subject controversial.


Opinions have differed greatly on the reality and, if real, the importance of terroir in determining wine qualities. Major regional classifications of European vineyards have been largely founded on the concepts of terroir, although these may be based on climate rather than soil. New World viticulturists and researchers, on the other hand, have tended to dismiss it as a product of mysticism and established commercial interest. Dickenson canvasses the issues in detail, and is likewise mostly sceptical. But against these views it might also be justly charged that ‘newer’ viticulture has notoriously attempted to imitate the products of the great vineyards without regard to terroir, and therefore has a commercial reason for belittling its potential contribution.

It can be argued that modern improvements in vineyara and winery technology, by raising and unifying standards of wine quality, have to some extent obscured differences in both style and quality of wines that in the past were (sometimes wrongly) attributed to terroir in its true sense. But paradoxically, the same improvements can serve to unmask genuine differences due to terroir. By eliminating extraneous odours and tastes derived from faulty wine-making, they allow the fuller expression of intrinsic grape qualities, which can be related to site. The wines of Burgundy are most often cited as evidence of the reality of the terroir effect. Many growers have different plots which they cultivate in the same way. They then vinify the grapes from these plots in a similar way, yet the wines produced differ significantly in quality and style, Guigal´s single-vineyard bottlings in Cote Rotie are another example of this approach to terroir.

Laville lists the following factors (components) as determining terroir:
- Climate, as measured by temperature and rainfall.
- Sunlight energy, or insolation, received per unit of land surface area.
- Relief (or topography, or geomorphology), comprising altitude, slope, and aspect.
- Geology and pedology, determining the soil's basic physical and chemical characteristics.
- Hydrology, or soil-water relations.


An essential notion of terroir is that all its components are natural, and that they cannot be significantly influenced by management.

The main emphasis in nearly all recent French writings is on the soil, and especially its role and interactions with other elements of the environment in governing water supply to the vine. The most important evidence for this comes from the studies of Dr. Gérard Seguin, of the University of Bordeaux. He found that, while many of the acknowledged best Bordeaux vineyards are on the Quaternary (recently laid down) gravelly sands, by no means all are. Neither geological origin nor soil texture could explain the region’s best terroirs, as judged by the wines they produce. The best in fact covered extremely diverse soil textures, ranging from heavy clays, as in Pomerol, through calcareous brown soils, to sandy loams and sands over clay (podzols), to the deep, gravelly sands most typical of the Médoc. An analysis of the soils’ chemical properties showed them also to be extremely variable.

Two unifying themes did, however, emerge among the top Crus. First, none of their soils was very fertile, but then none of the vines showed mineral element deficiencies either. Secondly, their soils regulated water supply to the vines in such a way that it was nearly always just moderately sufficient, without extremes in either direction. Drainage was always excellent, so that both water-logging and sudden increases in water supply to the vines were avoided no matter how much the rainfall. In the case of clay soils, this depended on their having fairly high organic matter  and/or calcium contents, so that they maintained friability and an open pore structure through which water could move readily.

At the same time, the capacity to store soil water within a soil depth accessible to the vine roots was great enough to ensure supply through prolonged rainfall deficits. This might be achieved either by great soil depth and a deep, sparse root system, in the case of sandy soils with little water storage capacity per unit volume; or a lesser depth in heavier soils, combined with a capacity of the clay and organic matter to hold some of the water tightly enough that it is only slowly available to the roots. The deep, gravelly sands of the Medoc exemplified the former situation, the heavy clays of Pomerol, the latter. This explained why the best terroirs maintain their wine quality notably better in poor seasons than the rest, a consistency which has always been one of the most striking features of the Bordeaux Classed Growths.


Van Leeuwen et al. found that the effect of soil is secondary to that of climate. However, both the climate and the soil effects are mediated through their influence on water supply to the vine.

Studies of terroir in Burgundy, cited and illustrated by Johnson, and by Halliday and Johnson, have led to similar conclusions. There the best wines are from stony clay loam soils, formed on the middle slopes from Marl (a clay and soft limestone mixture) mixed with silt and rubble from outcropping hard limestone further up. These soils combine good drainage with just the right capacity to store and supply water to the vines.

Extensive studies by Carbonneau and colleagues in the Bordeaux region, and by Smart and colleagues in Australia and New Zealand, have revealed a further common feature of vineyards producing the best wines. All have a high degree of leaf and bunch exposure to direct sunlight, with little complete shading of internal and lower leaves. Variation in this respect is explained by differences in vegetative vigour and vine balance. Best quality is associated with only moderate vigour, which typically results from a somewhat restricted water supply, limited nitrogen, and (in some cases) appropriate training systems. These studies suggest that soil effects on wine quality are indirect; i.e. soil conditions regulating water and nitrogen supply to the vine affect vine vigour, which in turn affects fruit and leaf exposure to sunlight, which in turn affects wine quality. While exposure to sunlight is amenable to management control on soils that are not too fertile, vine supply of water, in the absence of irrigation, is very largely not. It is therefore a prime contributor, together with local topography, to the immutable influence of terroir.

An implication is that geology, often cited as a basis of terroir, has in general no more than an indirect role. To varying degrees parent rock materials do contribute to the Matures of the soils derived from them; they also shape local topography and therefore mesoclimate. Occasionally the parent materials contribute directly because vine roots can penetrate them, as in the cases of chalk subsoils and the recent alluvial deposits of the Medoc. In the broad sense, however, it remains the soil itself, and its water relations, that play the decisive role.


The effect of terroir on wine quality is now quite well understood: it is mainly mediated through vine water supply by the soil and the climate, although mineral supply (and especially nitrogen supply) can also play a role. This effect of terroir can partly be obtained by good canopy and irrigation management in dry climates. However, the effect of terroir on wine style is still poorly understood. The high quality of Chx Ausone (limestone), Cheval blanc (gravel and clay), and Petrus (heavy clay) can be explained by the water regime. But why do they taste different and why do they each have their own style, despite very similar viticultural and oenological practices? This aspect of terroir is extremely interesting, because top wines are not only very good, but also unique, with their own style.

Another aspect of terroir is that its greest expression occurs when grape ripening is relatively slow and therefore late in the season. This occurs in cool climates, or in warmer climates when varieties are sufficiently late ripening. In all quality wine regions in Europe, growers have chosen varieties that just achieve ripeness under the local climatic conditions. When grapes ripen in August in the northern hemisphere, or in February in the southern hemisphere, it is very difficult to produce refined wines with sought-after aromatic expression. Terroir can only be understood when soil, climate, and vine are taken into account simultaneously. A poor understanding of terroir in New World countries has in some instances led producers to plant varieties regardless of the local climatic conditions. When early-ripening varieties are planted in warm climates, wines are heavy, lacking freshness and aromatic expression (except for aromas produced by wine-making practices). This is the case with warm climate Chardonnay, for instance. A much better expression is obtained in cool climates (Chardonnay in Chablis, Sauvignon Blanc in New Zealand). Growers in the: New World are becoming more aware of this; and seeking out cooler regions. Cameros instead of the Napa valley, for example, or high altitude vineyards in Argentina, New Zealand and Tasmania. 


An international concept?
The question remains as to how far the French concept of terroir, with its primary emphasis on soil, is relevant to other regions and viticultural systems. An overriding influence of soil and its water relations can be easily enough understood in the Bordeaux environment, with its relatively flat topography and, as a consequence, few really major differences in mesoclimate. The situation is clearly different in areas such as Germany’s Mosel-Saar-Ruwer region at the cold limit of commercial viticulture. The topographic differences between individual sites decide whether grapes, particularly the high-quality varieties such as riesling, will ripen fully at all. Topography and mesoclimate are inescapably major components of terroir (or its German equivalent).

Moreover, it has been argued that mesoclimatic differences may not merely govern the degree of ripeness attained. Some believe that they could also affect more subtle grape and wine qualities of the kinds commonly attributed to terroir. Soil might similarly influence grape and wine qualities through its effect on microclimate.

The New World approach to vineyard design is now much more likely to take soil differences into account. New World vineyards were once most likely to have been subdivided according to existing boundaries, shape, topography, or whim. Today it is increasingly common to allow a soil survey and soil mapping to determine choice of variety, root-stock, even trellis system a concession to the wisdom of Old World experience.

Any such effects serve, of course, to underline terroir as a real concept, and not something expressed merely through the relationships between vine vigour, balance, and the vine canopy. The distinction is critical because, to the extent that the latter is true, other approaches are often available to achieve the same end. Two stand out in importance.

1. The use of larger or more complex vine training systems, such as Carbonneau’s Lyre trellis, making it possible to maintain good leaf and fruit exposure on larger and more productive vines. This in turn allows the exploitation of moister, and possibly more fertile, soils, giving higher yields without any necessary loss of fruit and wine quality.

2. In regions with dry summers the use of controlled irrigation, especially that made possible by drip irrigation. This allows vegetative vigour to be held at appropriate levels for vine balance, but water to be supplied during ripening as needed. It is an important advance in regions of mediterranean climate, enabling them to duplicate many of the terroir characteristics of the long-established best table wine areas, but with fewer climatic risks.

It seems inconceivable, however, that these developments will ever totally eliminate the regional and local differences in wine qualities that have been traditionally ascribed to terroir. Differences in macroclimate, mesoclimate, and soil microclimate remain, while there are many conceivable avenues by which differences in soil chemistry (for instance, in trace element balances) might have small effects on wine flavours and aromas which are nevertheless detectable by the sense of taste. To the extent that terroirs remain unique, and poorly understood, one can therefore hope that they will continue to help mould the infinite variety and individuality of the best wines, giving the special nuances of character that make wine such a fascinating study for winemaker and consumer alike. Vivent les differences!


Source: www.earthvisioninc.com

Terroir is an elegant notion, a single word that symbolizes a complex system of particulars no matter how narrowly or broadly you define it. On the narrow end, some would have it refer only to the aspects of physical place (geology, topography, soil, and climate) that influence the quality and character of wine. On the broad end, the term includes the effects of viticulture and winemaking, the people involved, and cultural aspects as well. If the word was English or Italian, few would pay much attention, but the notion is French, from the land that we all look to as the historic seat of fine wine.

Terroir is surely an elegant term, but its contribution to understanding and enjoying wine is a bit unclear. We can discuss terroir and wine from a philosophic or academic standpoint forever, but put a bottle of wine on the table and ask even the most devout terroirist how it reflects the place from which it came and the answer is often a halting account of soil and climate, some observations perhaps about viticulture and winemaking, but little reference to the wine itself. It seems difficult at best to express how any particular bottle reflects terroir, or even what aspects of wines from a particular region reflect its terroir.

If the purpose of the notion of terroir is to link wine with place (to provide information about wine provenance) we can find perhaps a more direct path, framing the discussion in a comfortably familiar way by focusing on place, people, and culture. In this way we can provide a clear context within which to think about, and taste, wine.

Place includes the physical aspects of terroir (geology, topography, soil, and climate). All of these are known to influence vines, grapes, and wine, either directly or indirectly. Climate (temperature, rainfall, solar input) is the easiest to measure and understand. Topography controls sun aspect and solar influx. Geology and soil affect vine growth and grape character at least through their influence on drainage and the availability of water, perhaps through supplying trace minerals, and also through their effects on microbiology.

People provide the link between place and wine through the processes of viticulture and winemaking. Warren Winiarski, maker of the wine that won the fabled 1976 Paris wine tasting, has long maintained "Without people there is no terroir." If wine is, as they say, "made in the vineyard" then every one of the myriad of decisions made by viticulturists (rootstock, clone, vine spacing, trellis design, pruning styles, picking dates) affects the character of grapes and wine. And even the least interfering of winemakers makes hundreds of decisions in the winery (ferment with whole cluster or destemmed fruit, cold soak, natural or cultured yeast, and so on) that affect the character of wine in the bottle.

Culture is easy to perceive as the most distant influence on wine character, but just think of three cultural elements--tradition, habit, and regulation--and their influence on wine. In Burgundy, for example, grape variety, planting density, pruning regimens, harvesting dates, sugar content, maximum yields, vine age, are all set by law. In the United States, all of these are open to choice. The specific effect of these differences might be difficult to measure but it's clear that greater choice gives winegrower and winemaker more influence on the final product, creating a greater variety of styles within any given region.

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