To blind taste proficiently, it is necessary to have at least some basic notions of viticulture and winemaking. Long gone is the era in which wine was flavoured with herbs and spices, or diluted with fresh or salt water. For our purposes, wine is made from grapes and grapes alone: although wine may be described in terms of fruits, flowers, and so on, for the most part these aromas and flavours derive from the grapes themselves. Other aromas and flavours arise from processes in winemaking and maturation, including maturation vessels and especially oak barrels.
‘I am the vine’, said Jesus, ‘you are branches … for without me ye can do nothing’ (John 15:5). Today, almost all wine is made from the fruit of the Eurasian grape vine, Vitis vinifera. Over thousands of years, man domesticated the dioecious1 forest creeper V. vinifera silvestris into the hermaphroditic crop-bearing V. vinifera sativa. Its success owes to its adaptability, its readiness to self-propagate, and, of course, its heavy crop of flavoursome fruit with high levels of sugar that can readily be fermented into alcohol.
Today, over one thousand identifiable varieties of V. vinifera are commercially cultivated to make wine. Some of these varieties are ancient, others much more recent, often the products of modern cultivation and crossing techniques, although not (yet) of genetic modification. A single variety can have several clones, which, although closely related, are genetically distinct, each with differing properties such as better disease resistance, higher yield, earlier ripening, deeper colour, or a more complex aroma and flavour. Whether a plant is counted as a clone or a separate variety can be a matter of debate, especially among us blind tasters!
Other species of Vitis include V. labrusca, V. berlandieri, V. riparia, and V. rupestris, which are native to North America, and V. amurensis, native to the Far East. Early settlers to North America cultivated V. labrusca, and labrusca varieties such as Concord are still entertained on the Eastern seaboard of the United States. Hybrid crosses of vinifera and non-vinifera vines such as Seyval Blanc, Vidal Blanc, and De Chaunac are more commonly found in North America than in Europe, not least because the European Union prohibits their use in quality wine. By far the most important contribution of non-vinifera vines to modern viticulture has been to provide phylloxera- and nematode-resistant rootstocks on which to graft vinifera scions (see later).
It has become a cliché that ‘good wine is made in the vineyard’. While one can make bad wine from good grapes, one cannot make good wine from bad grapes: a balanced wine can only be made from balanced grapes.
As they ripen, grapes concentrate sugars that can be partly or wholly fermented into alcohol. The amount of sugar in the grapes, or ‘sugar ripeness’, corresponds to the potential alcohol of the wine. ‘Phenolic ripeness’ on the other hand refers to the maturity of flavour in the grapes, as determined by examining and sampling them. With increasing phenolic ripeness, the grape skin, pips, and stems change colour, the grape skin and pulp texture become softer, and the tannins in the grape skin and pips become less bitter.
Although sugar ripeness and phenolic ripeness are related, they do not necessarily go hand in hand. In overly hot conditions, grapes can reach sugar ripeness before they arrive at phenolic ripeness. The grower is then caught between Scylla and Charybdis: either pick early to make a wine with astringent tannins and a green streak; or wait to make a full-bodied, alcoholic wine that is flat and flabby and lacking in acidity. Conversely, in overly cool conditions, grapes can struggle to accumulate sugars, and turn into wines that are unpleasantly thin and acidic.
Grape ripening is a function of sunlight and heat, which can vary markedly from one region to another and even from one vineyard to the next. One of the challenges for the grower is to arrive at ripe-tasting fruit with optimal levels of sugars and acids. This balancing act calls upon a finely honed understanding or appreciation of the vine’s interaction with elements of its environment, from climate, topography, and geology down to the life cycles of local plants and insects and the feeding patterns of birds, bats, boars, and baboons. These all are aspects of terroir, a French concept that denotes the entire ecosystem of a vine and vineyard. At its broadest, terroir also encompasses local customs and traditions honed over decades and centuries, including methods of planting, training, harvesting, and even winemaking and ageing.
A vine with an ample supply of water and nutrients tends to expend its energy on foliage rather than fruit. For it to focus on fruit, it must come under sufficient stress that it feels the need to propagate its genetic material. The quality of fruit produced depends to a large extent on the climate, which in turn depends on a number of geographical factors such as latitude, altitude, proximity to the sea or ocean, and exposure to prevailing winds.
Whereas ‘weather’ refers to short term or exceptional events such as rains, frosts, hailstorms, flooding, and drought, ‘climate’ refers to long-term underlying patterns measured in terms of sunshine hours, mean temperature, diurnal temperature range, rainfall, humidity, and such like. Broadly, macroclimate describes the climate of a particular region, mesoclimate the climate of a particular sub-region or vineyard site, and microclimate the specific conditions in a small part of the vineyard or even within the canopy of a single vine.
Grapes require a certain amount of warmth and sunshine to arrive at sugar and phenolic ripeness. But too much heat can impede ripening, and too much sunshine can burn the grapes. The best results are obtained in temperate climates with a growing season that extends over 180 or more consecutive frost-free days with average temperatures of 16-21°C and more than 1,250 sunshine hours. The judicious exploitation of mesoclimates, varieties, rootstocks, trellising methods, canopy management techniques, irrigation, and harvest times can mitigate adverse or borderline macroclimatic conditions. Outside the growing season, vines are able to tolerate freezing conditions, but sustained double-digit negative temperatures can lead to damage and even death. In Cahors, the Great Frost of February 1956 killed off all but 1% of the vines.
The world’s most successful wine regions lie within latitudes 30-50° North and South. Within these diverse temperate zones, some grape varieties such as Riesling, Pinot Noir, and Sauvignon Blanc do best in cooler, more marginal climates. Others, such as Grenache, Nero d’Avola, and Touriga Nacional call for much hotter conditions. Cabernet Sauvignon insists on a moderate but sunny climate, whereas Chardonnay is adaptable, yielding lean and mineral wines in cool Chablis but blousy and buttery wines in hot parts of South Australia. Generally speaking, white varieties need less heat than black varieties, and so predominate in the coolest, most marginal regions such as southern England, Champagne, and the Mosel. Wines from such marginal regions may be softened or made more palatable by double fermentation, arrested fermentation (to retain residual sugar), the addition of sugar, or ageing on the lees.
Of course, the geographical distribution of a grape variety is determined not only by climate, but also by cultural, economic, and even legal factors. Stellenbosch may enjoy a Mediterranean climate, but plantings of Italian or Spanish varieties are nonetheless rare.
Regions that are in the interior of a large landmass or sheltered from the sea by mountains (or both, as with Alsace, Ribera del Duero, and Alto Adige) are described as continental, with cold winters and hot, relatively dry summers. In contrast, coastal regions such as Bordeaux or the Mornington Peninsula with direct exposure to the sea are described as maritime, with warmer winters and milder, wetter summers. Some regions such as Châteauneuf-du-Pape and Chianti are best described as Mediterranean, with mild winters and very warm and dry summers. A similar ‘Mediterranean’ climate can also be found in parts of California, Western and South Australia, central coastal Chile, and the Western Cape in South Africa.
Altitude can make it possible to produce quality wine in hotter regions such as the Duero/Douro Valley, Mount Etna, Cederberg, and Mount Canobolas. As a general rule, for every 100m (328ft) of ascent, the mean temperature drops by 0.5-0.6°C. Higher altitudes are also associated with cooler nights and greater diurnal temperature variation, which enable grapes to ripen and concentrate flavour while preserving natural acidity.
In more marginal regions such as the Rheingau or Côte de Nuits, vines are more often planted on steep slopes. At higher latitudes, slopes, depending on their exposure, can receive much more incident sunlight than flatlands, especially during the critical autumn ripening period. Slopes also offer thinner topsoil, better drainage, and increased air circulation from convection currents. In the northern hemisphere, many vineyards are planted on south-facing slopes to capture as much sunlight as possible, and vice versa in the southern hemisphere. Conversely, in hot climates, vineyards are often planted on north-facing slopes to take advantage of the cooler conditions. In general, slopes that face south-south-east or south-east are most favoured because they receive the first sun and warm up and dry out more quickly. In many regions, they are also sheltered from the prevailing winds. Steep slopes do have some disadvantages: they are prone to erosion and the vines can be expensive and dangerous to access. In the Mosel, some of the slopes are steeper than 45°, with the steepest, Bremmer Calmont, at 65°.
Water bodies such as oceans, rivers, and lakes also exert an important influence on climate. Maritime air blown off the Antarctic Benguela current makes Hemel-en-Aarde in Walker Bay much cooler than more inland regions such as Stellenbosch, Paarl, and Swartland. With average summer highs of just 25°C, on a par with Burgundy, Hemel-en-Aarde is reputed for its fine Chardonnay and Pinot Noir. The River Loire moderates temperatures, as does the River Mosel, making viticulture possible at such high latitudes. Rivers also reflect sunlight, increase air circulation, and provide water and transportation. Sea mists that form off the Californian coast penetrate far inland into regions such as Mendocino Valley, exercising an important cooling influence; and mists from the River Ciron in Sauternes or Lake Neusiedl in Burgenland create ideal conditions for the development of noble rot (see later).
Even trees and other plants have a role to play. The Forêt des Landes shields Bordeaux from strong and salty winds. On a much smaller scale, trees and hedges shelter a vineyard from gales and storms and stabilize steeper slopes. Ground cover crops protect the soil from erosion and runoff, improve soil structure and fertility, provide a habitat for beneficial predators, and promote biodiversity. A monoculture of vines on a flat and featureless expanse of land treated with synthetic fertilizers, herbicides, fungicides, and pesticides enables the farmer to machine harvest a heavy and consistent crop, but does nothing for the quality of the grapes or the long-term health of the soil and environment. More and more, growers are learning to work with, rather than against, nature.
Soils are complex, layered systems, with the visible topsoil of critical importance only to very young vines. As a vine ages and develops, its roots dig deep into the subsoil in search of water and nutrients. A vine must come under some strain to produce high quality fruit, and most vineyards are planted on thinner, poorer soils that stress the vine and promote deep rooting into the mineral-rich subsoil. Happily, the best vineyards are seldom suited to other forms of exploitation, which, in regions such as Burgundy, the Rhône, and the Douro, has preserved them through the ages.
A soil that is heavy in clay (particles up to 2μm in diameter) behaves like a sponge, expanding and contracting in function of its water content. It is compact and hard to penetrate, and in a dry spell can crack and damage the roots of the vine. A clay-based soil is only suitable for viticulture if it contains substantial proportions of larger particles such as silt (2μm-0.05mm) and sand (0.05mm-2mm), which lend it a lighter, loamier texture. Gravel (>2mm) is the lightest and best draining of all soil types, with the added advantage of retaining solar heat. Some varieties do best on gravelly soils, while others prefer clay-based soils. Thus, in Bordeaux, Cabernet Sauvignon prevails on the gravelly Left Bank, while the clayey Right Bank is mostly given to Merlot. A sandy soil, if not too sandy and dry, can offer good drainage and high heat retention and discourage pests and disease. Sandier soils, as in the Graves, Roero, or Swartland, are held to produce softer, lighter wines with greater perfume and lighter acidity and tannin.
Sedimentary soils such as limestone and chalk that developed from fossilized seashells have been favoured for centuries. Although free-draining, they are able to retain moisture through dry spells. They also facilitate deep rooting and preserve the acidity of the grapes. Calcareous soils underlie the success of such diverse regions as Saint-Emilion, Châteauneuf-du-Pape, Piedmont, Chianti, Rioja, Jerez, Coonawarra, and the south of England, which lies on the Kimmeridgian Ridge, an ancient seabed of limestone clay running through the vineyards of Champagne, Chablis, and Sancerre.
Soils of volcanic origin are a feature of Napa Valley, Willamette Valley, Mount Etna, Santorini, and Kaiserstuhl, among others. Volcanic soils are very diverse in composition and decomposition, and may contain various combinations of basalts, tuffs, pumices, and sand. Owing to their porosity and relative fertility, they tend to yield riper, richer wines with greater acidity, minerality, and longevity, although some of these properties may derive at least in part from such factors as slope and altitude.
Other important soil types that crop up throughout this book are alluvium, a river deposit composed of clay, silt, sand, and gravel; marl, a friable deposit composed of clay and lime (limestone can be considered as a purer, lithified form of marl); tufa, a porous rock composed of silica and calcium carbonate and precipitated from a source of water such as a spring or lake; granite, a hard and coarse-grained igneous rock composed of feldspars, quartz, and other minerals; and schist, a coarse-grained metamorphic rock with a foliated, often flaky, structure composed of mica and other minerals. Schist, slate, and gneiss are foliated metamorphic rocks that originate from shale, which itself originates from the consolidation of clay. Whereas schist is a medium-grade metamorphic rock, slate is low-grade and gneiss high-grade.
The phylloxera louse (Daktulosphaira vitifoliae), native to North America, is the most devastating of all vineyard pests. American vines are resistant to the louse, but not so V. vinifera. The louse disembarked in France in the early 1860s and set about ravaging the vineyards of Europe. The life cycle of the louse is complex: in a nutshell, the damage is inflicted by the crawling form of the insect, which disrupts the root system of the vine and exposes it to secondary infection. The discovery that resistance can be conferred by grafting vinifera vines onto American rootstocks led to replanting on an unprecedented scale, often, as in Bordeaux, Jerez, or South Africa, leading to important changes in the balance of grape varieties. Today, phylloxera continues to pose a near universal threat, and almost all vinifera vines are grafted onto American rootstocks. Geographical isolation and strict quarantine measures have so far preserved South Australia and much of Chile and Argentina from the pest, but it can only be a matter of time before it rears its ugly head.
Most other vineyard pests are insects such as beetles, flies, mites, caterpillars, moths, and locusts, although larger animals such as birds, rabbits, boars, monkeys, baboons, kangaroos, and snakes can also destroy crops and damage vines as well as imperil vineyard workers. Some of these insects can be controlled with sulphur or chemical pesticides, although ‘integrated pest management’ (IPM, ‘sustainable viticulture’, lutte raisonnée, culture raisonnée) often presents a more effective and less damaging alternative.
With IPM, synthetic chemicals can be used, but only in small amounts and as a last resort once non-chemical interventions have been exhausted. Such interventions may include selecting disease-resistant varieties and rootstocks, improving soil structure, planting cover crops, and introducing or encouraging natural predators. IPM can be close to organic viticulture, which seeks to achieve a natural balance in the vineyard by using nothing more than certain natural preparations. Biodynamic viticulture, which derives from the 1924 lectures of Austrian philosopher Rudolf Steiner, goes one step further by looking upon the farm as an ecosystem, starting with the soil, which is treated as a living organism. In addition, biodynamic practitioners seek to connect the farm with natural rhythms by aligning operations with lunar and other cycles.
Before phylloxera, the vineyards of Europe had been battling with powdery mildew or oidium (Uncinula necator), a fungal disease that, like phylloxera, had come from America. Unlike most fungi, oidium prefers dry conditions. The first symptoms of infection are whitish powdery patches on the undersurfaces of basal leaves, but canes, flowers, and fruit can also be affected. Diseased berries fail to thrive and may split open. The original solution of spraying or dusting sulphur onto the vines is still practised, assisted by canopy management techniques that increase air and light penetration.
Vines are also susceptible to a number of other fungal diseases such as downy mildew and grey rot, which, like noble rot (see later), owes to Botrytis cinerea. Many of these diseases can be prevented by canopy management techniques and copper-containing sprays such as Bordeaux mixture, although harsher treatments can be required. Some fungal diseases, notably oak-root fungus, attack the roots of the vine and are difficult to detect let alone treat. Eutypa dieback is a fungal infection of the trunk and branches of the vine that may be introduced through grafts and transmitted on infected shears at the time of pruning. The damage is often confined to one arm of the vine, whence the byname ‘dead arm’. There is no treatment, but other parts of the plant remain largely unaffected. When life gives you lemons, make lemonade: Dead Arm Shiraz is a premium wine made by d’Arenberg from old Eutypa-infected vines in McLaren Vale. Historically, rose bushes planted at the edge of vineyards alerted vineyard workers to fungal diseases such as powdery mildew and downy mildew, with the delicate rose bushes developing signs of disease in advance of the vines.
Prevention is the most effective, and often the only, cure for bacterial and viral infections. It involves disinfecting the soil prior to planting; observing the strictest standards of hygiene in grafting, pruning, and other operations; and, if possible, controlling vectors of disease. For instance, Fanleaf virus is transmitted by nematodes in the root system, and can be controlled by grafting vines onto nematode-resistant American rootstocks.
Vines are generally propagated through cuttings which preserve the genetic makeup of the particular grape variety or clone. This can be achieved either by taking and planting cuttings, or, less commonly, by burying a branch of an existing plant, so-called layering, which is still practised in some phylloxera-free vineyards. Layering preserves the identity and genetic diversity of a vineyard, but another and better method of propagation is ‘massal selection’, which involves taking cuttings from the most outstanding vines in the vineyard or nearby vineyards. In most places, vinifera cuttings must be taken to a nursery and grafted onto American rootstocks to protect them from phylloxera. Grafting onto American rootstocks can also protect against other pests and diseases and supply a root system that is better suited to the climate and soil type. Young vines are typically planted in rows to facilitate vineyard operations, but can also be planted pell-mell, or en foule. Closely spaced vines compete with one another for nutrients and water, which can help to stress the vine into producing higher quality fruit.
Old vines generally make for better wine, if only because they are less vigorous with more restricted yields. This, however, should not be overstated: the Great Frost of February 1956 required large scale replanting in Saint-Emilion and Pomerol, but the youth of the vines did not prevent the 1961 vintage from achieving cult status. In fact, like old vines, very young vines (within three-to-five years of the first harvest) are less vigorous and so produce superior fruit.
After planting, vines need about three years to establish themselves and start bearing quality fruit. In these early years, they are especially vulnerable to harsh sunlight, droughts, frosts, insects, and so on. Being natural creepers, they require some form of support on which to develop and fruit. Trellises range from a simple stake in the ground to elaborate overhead pergola systems. A simple structure, while cheap, may render vineyard operations more difficult and costly. The choice of trellis is also contingent upon other factors such as the chosen grape variety, the vigour of the vine, the aspect of the vineyard, and the potential for hazards such as storms and frosts. In practice, vines are often trained along one or more horizontal wires to optimize the microclimate and facilitate vineyard operations.
A common training system is the single or double Guyot system. With single Guyot, each vine has one cane held back to support the following season’s fruiting canes, and one spur, which gives rise to the replacement cane. With double Guyot, there are two canes and two spurs, with the canes trained in opposite directions.
The Guyot system dates back to the 19th century, when most vines were trained in a bush (gobelet), with the spurs arranged on short arms in an approximate circle at the top of a short trunk (hence gobelet or ‘cup’). This ancestral system, which does not require supporting wires, is still favoured in some regions with a dry climate and infertile soils, most notably Châteauneuf-du-Pape, where it offers greater resistance against wind and drought.
Cordon training is similar to gobelet, with a short trunk and spur pruning. However, instead of head training, one or two spur-bearing permanent branches, or cordons, are trained along a wire. Unilateral cordon training, with a single permanent branch, is sometimes referred to as cordon de Royat.
The modern Scott Henry training system for overly vigorous vines is similar to double Guyot, but with two canes running out to either side. On either side, the fruiting canes on the upper cane are trained upwards, and those on the lower cane are trained downwards. The Smart Dyson training system is a variation on the Scott Henry with cordons instead of canes.
Other common training systems include vertical shoot positioning (VSP), with the fruiting canes trained vertically on four to six levels of wire; the Geneva double curtain (GDC), which reduces shade from a dense canopy by splitting it into two; and the lyre which is similar to the GDC but with the fruiting canes trained upward rather than being left to hang down.
Traditionally, pruning to remove old wood kicked off on 22 January, the Feast of Saint Vincent of Saragossa, patron saint of winemakers (the patron saint of vines is Pope Saint Urban). In the main, the functions of pruning are to: (1) optimize the balance between vegetative growth and fruit production by controlling the size and shape of the vine; (2) remove dead, broken, or diseased tissue; and (3) regulate bud break.
There are essentially just two pruning methods, short (cordon/spur pruning) and long (cane pruning, traditionally used with the Guyot system among others). Spur pruning is easier, at least while the cordons remain healthy, but cane pruning is more flexible and offers better frost protection.
With spur pruning, the gnarly main branch or cordon is left intact. Spur positions on the cordon typically support two one-year old canes. The cane positioned further away from the cordon is completely taken out including about 5mm of the old wood. The remaining cane is pruned short, typically to two buds and just a few inches. This short cane is called a spur.
With cane pruning, the two-year-old cane carrying most of the previous season’s growth is completely taken out. One or more well-formed one-year-old canes are then selected and pruned to about six-to-ten buds and one-to-two feet long, before being tied down in early spring. Replacement (or renewal) spurs, which have been cut back to two or three buds, are also left behind to provide the next season’s one-year-old canes.
The vine jumps to life in mid-spring: buds appear and tiny leaves and embryonic tendrils emerge from the buds. The vine is now susceptible to spring frosts, and a frosty night can destroy the entire harvest. Pruning late delays bud burst and can help to protect against spring frosts, as can sprinklers, smoke-belching smudge pots, wind machines, and helicopters, among others.
The shoots grow rapidly over the coming months and need to be positioned according to the trellising system and pruned back to restrict vegetative growth. As it develops, the foliage begins to affect the microclimate surrounding the flowers and fruit, and may need to be thinned or adjusted to optimize the ripeness and quality of the crop. Canopy management, a term coined in the 1980s by viticulturalist Richard Smart, can usefully increase or decrease sun exposure, restrain vegetative growth, promote air circulation, and protect against vine diseases. Growers of Marlborough Sauvignon Blanc may cut back the leaves so as to uncover only one half of the fruit. This leads to a wine with both ripeness of fruit and a fresh grassy note.
By early summer, bunches of proto-grapes—caps of fused petals—have formed. Flowering begins when these caps fall off and the tiny stamens are exposed for fertilization. This is another critical juncture in the vine’s development: adverse conditions at flowering, which lasts something like one or two weeks, can lead to various degrees of coulure and millerandage, that is, failure of grape development and uneven development. Crop potential is a function not only of this season’s weather conditions, but also of the previous season’s, when this season’s fruiting buds were forming.
Berries develop over the summer months, accumulating water, sugars, acids, and other flavour compounds. In late summer, the berries change from mid-green to black, red, or pale green. This colour change, called véraison, marks the beginning of the ripening period during which sugars accumulate more rapidly, the harsh acids soften, and the tannins, anthocyanins, and other phenolic flavour compounds develop and mature. Green harvesting around véraison to remove immature bunches of grapes can improve the rest of the crop, especially in areas with vigorous vines or high yields.
In recent years, Burgundy in particular has fallen victim to violent summer hailstorms, with grapes and vines suffering significant damage. Netting, which is common in hail-prone Mendoza, can be effective against hail, and is currently being tested in Burgundy. Unfortunately, netting is expensive and blocks out some sunlight, which could present much more of a problem in Burgundy than it does in sunny Mendoza. Hail might be prevented by seeding clouds with nuclei in the hope of reducing the size of the hailstones. Clouds can be seeded with ground-sited silver iodide smoke generators, or airlifted silver iodide or dry ice dispensers. Traditionally, church bells were pealed at the approach of hail clouds, and, today, some estates use hail ‘cannons’ in the hope of disrupting hail formation with shock waves. In Bordeaux, Château d’Issan introduced hail cannons after losing over half its crop to hail in both 2008 and 2009. It is hard to verify or quantify the effectiveness of cloud seeding and hail cannons, and many people remain skeptical.
In the autumn, the grapes reach optimal sugar and phenolic ripeness (ideally at the same time) and are ready for harvest. The grapes are harvested by hand or machine and whisked away to the winery where the fermentation process can begin. Meanwhile, the vine stores complex carbohydrates in its canes, trunk, and roots to sustain it over the winter. The leaves are shed, shoots lignify, and the plant falls into dormancy.
For sweet wines, the grapes need to be left on the vine for longer, with one or several pickings required. Luscious botrytized wines are made from late harvest grapes infected by Botrytis cinerea. Unless the infection is carefully managed, it can lead to grey rot rather than noble rot. For noble rot to develop, the berries must have ripened to a potential alcohol of at least 7%, from which point the fungus can feed on the berry without damaging or splitting it. The fungus punctures the skin, gradually shriveling the berry and concentrating its sugars and aromatics. Mesoclimates suited to the development of noble rot such as Tokaji, Sauternes, and Coteaux du Layon feature autumn mists that dissipate mid-morning to make place for dry and sunny afternoons. In other cases, grapes are left to dry on the vine and then harvested, or else harvested and then dried, traditionally on straw mats, to make straw wines. Grapes can also be left on the vine until partially frozen by a deep winter frost. They are then harvested in the dead of night and pressed to extrude the ice crystals and produce tiny quantities of super-concentrated ice wine (Eiswein), which is a specialty of parts of Germany, Austria, and Canada.