TERROIR AND TECHNOLOGY

For some, wine must be as natural a product as possible; others welcome any improving human intervention.      Chris Bargmann CWM hopes that technological advances will aid, and not obscure, what nature offers.

‘Terroir’ has become an international industry buzzword. It is a concept that is invariably linked to the best vineyards – and undeniably a handy marketing tool for some. But as increasing quantities of well made wines are churned out, there is the danger of losing touch with the factors that potentially individualise the wines of different regions. Are winemakers becoming so dominant, and technology so sophisticated, that following a winemaking recipe will lead to a wine with a specific taste profile? How much does the vineyard matter?

Terroir describes the total natural environment of the vine in a particular site. Bordeaux property-owner Bruno Prats’s definition is a good one: terroir ‘looks at all the natural conditions which influence the biology of the vinestock and thus the composition of the grape itself. The terroir is the coming together of the climate, the soil and the landscape. It is the combination of an infinite number of factors: temperatures at night and day, rainfall distribution, hours of sunlight, slope and drainage to name but a few.’

Theoretically terroir excludes human influence, but a sense of place, local history and tradition must also be accommodated. Where, though, does ‘terroir’ stop, and man’s influence take over? Even apart from what happens in the winery, viticulturalists can improve the growing conditions of the vine, and new clones can send better quality fruit and new flavours to the winery. Sceptics point out that new vineyard techniques mean that top quality wine now depends less on specific terroir sites. In addition, the increasing dominance of labelling wines according to grape variety has seen an explosion of wine styles owing more to grape flavour profiles than to place. Blending across regions also counters the importance of specific sites – Australia has been at the forefront of this practice at all quality levels, and in South Africa the ‘Coastal Region’ invoked so often on labels is a vast and disparate area.

It is worth looking more closely at the most important natural aspects of terroir.

Climate

Climate is the most immutable of these elements. We can do little, global warming aside, to alter the climate of an area, so vines must be chosen to suit local conditions. Riesling, for example, is normally associated with cool climates, while shiraz and grenache are at home in the heat. Three types of climate are generally referred to in relation to viticulture. Macroclimate refers to a whole region, mesoclimate to a much smaller area – perhaps an individual vineyard or estate – and the subtleties associated with topography, altitude and soil start being perceptible on this scale. Microclimate is measured in millimetres or a few metres – the site, for example, of an individual vine. This is the type of climate most susceptible to viticultural influence, through such practices as trellising, orientation, pruning, and canopy management.

The French, above all, have behind them invaluable centuries of experience in matching site and grape. In the Cape, despite a lengthy winemaking heritage, experience is limited, and even recent decades have seen little advance. In part this has been because producers generally follow the New World approach of emphasising the variety. California, however, at its top end of production,  has for some years been becoming much more sophisticated in identifying the best area-grape matches, and some patterns are beginning to emerge in South Africa too: Groenekloof and Constantia for sauvignon blanc, for example, and the Hemel en Aarde Valley for pinot noir and chardonnay. A distinctive regional character is becoming discernible in the wines of Constantia, particularly amongst its whites. Only time, of course, can reveal the characters of particular terroirs independent of winemaking practices.

Soil

The second important element of terroir is the soil and, indirectly, bedrock geology. Here we are perhaps at the heart of the concept. Soil type, its structure, nutrient content and drainage qualities, directly affect the vine’s growth.

The soil may influence the ripening period of the grapes and, together with climate, make for an environment capable of producing top quality grapes – and hence wine. For example, in areas prone to high rainfall, such as parts of New Zealand and Bordeaux, sandy or gravely soils with good drainage are desirable. In contrast, the clay-rich Hutton soils of the Cape winelands retain sufficient water during dry summers for vines to grow and produce grapes successfully.

Generally speaking the soil is the major influence on vine growth, as it provides moisture and nutrition, but the bedrock beneath it can also have an effect. Granite, for example, forms acidic soils where root growth can be restricted, whilst limestone or chalk produce low-acid soils with a low iron content, which may lead to chlorosis in vines. Human intervention is a possibility in such cases, through improving the soil properties before planting a vineyard, and by selecting appropriate vine rootstocks.

Aspect

The third important component of terroir is aspect – the topography of the land and, specifically, the orientation of hillside slopes, as this can modify the mesoclimate. In cool northerly areas like Burgundy, Champagne and Germany, slopes facing east and south will maximise the vine’s exposure to sunlight – important in achieving ripeness and quality. In South Africa, of course, south-facing vineyards are favoured as they will be cooler, a distinct advantage in a hot wine region.

A vineyard’s altitude above sea level is a related matter, and important in both hot and cool wine regions, as average temperature falls by approximately 0.60C with every rise of 100 metres. Thelema and Cordoba are good examples of producers combining the benefits of altitude and south-facing slopes to provide a cooler mesoclimate. In the case of Cordoba, situated in a lofty position on the  Helderberg, the cooling influence of breezes from False Bay, is an additional benefit.

The challenge to terroir

Dramatic technological changes in both winery and vineyard over the last decades have meant increasing human influence over the taste of wine. In the vineyard, improved clones, canopy management techniques, controlled irrigation and soil improvement all have their effect. In the cellar, cold fermentation, to give just one example, has immeasurably improved the quality of white wines in hot climate areas, and practices like micro-oxygenation, centrifuging and reverse osmosis are increasingly used. When top Bordeaux winemakers concentrate the product of their famous vineyards by removing water from the grape juice, what does this mean for the accurate reflection of the terroir of the particular vintage? Has the technologist-winemaker now taken definitive control? Is terroir under threat?

Realistically, we must conclude that human influence is the most important factor in making wine today. Perhaps the most significant change in the wine industry and the biggest challenge to terroir comes from cross-regional blending and, particularly, the increased use of varietal labelling. Many producers, even of ultra-expensive wines, aim for varietal character rather than seeking to express a distinct regional (terroir) taste, resulting in wines with broadly similar profiles, whatever their origin. Such wines will remain significant, particularly as modern consumers are more familiar with the tastes associated with the main varieties than the subtler aspects related to distinct regions or terroirs. It is the marketing of these varietal wines as representative of the local terroir that is likely to cause debate in the future.

The overall standard of wines everywhere has undoubtedly risen as a result of improved technology and scientific understanding of the processes involved in the vineyard and winery, but we are far from being able to replicate the world’s great wines regardless of the source of grapes. Fortunately, ambitious New World producers are increasingly waking up to the potential of their own terroirs through identifying their best vineyard sites.

As for great wine, however, the definition used by the late Peter Sichel (negociant and owner in Bordeaux) of what makes it great is convincing. The character of a wine, he suggests, is defined by the terroir of the vineyard, the quality is mainly determined by people, whilst the wine’s personality is determined by the weather. More controversially, an ‘extremist terroir-ist’ could argue that the only producers who can really claim to capture terroir in their wines are those who practice organic or biodynamic viticulture, where human interference in the natural balance is at its minimum.

EXPLORING CAPE TERROIR

The unique qualities of the terroirs of the Cape winelands are not well understood. The climate is ideal for grape production, but most vineyards are considerably warmer than Europe’s best sites, and it is encouraging to see the ongoing development of cooler areas along the coasts and at altitude in districts such as the Swartland and the Overberg. The Western Cape also lends itself to exploiting the benefits of aspect, though mention is seldom made of particular varieties’ suitability  to specific slope orientations.

Soils and geology also have the potential to offer something unique. Granite and shale predominate, varyingly, in the Coastal region. Limestone bedrock and lime-rich soils are rarer, and are best developed as the ‘Karoo soils’ of the Breede River valley. River gravels are common in many local vineyards, though few producers seem to be following the link between gravelly soils and quality wine seen in Bordeaux and elsewhere. The clay mineral kaolin is another potentially unique element in Cape soils (particularly in the Stellenbosch area), and undoubtedly affects the growth of vines – but is rarely mentioned by producers. Mineralization containing tin, present in parts of the Bottelary and Durbanville hills, is another feature worth mentioning; Saxenburg, Jordan and Kaapzicht all have vineyards near tin deposits and it does not seem to have done their wines any harm.

While South Africa has made some clear advances in defining its terroirs, the best matches of grape variety to the diverse vineyard sites will take time, and requires an understanding of how subtle changes in aspect, soil and geology affect different vines and rootstocks.

THE TERROIR PROJECT

A major research project into furthering the understanding of the Cape’s viti-cultural terroirs is being undertaken at Stellenbosch University and Nietvoorbij, under the leadership of Victoria Carey. A central component of the project is to establish a cost-effective and practical way of identifying terroir units. The complex topography, soil diversity and proximity to the ocean of Stellenbosch will be a focus for investigation. Grape will report on this exciting research in future editions.

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