The Importance of Viticulture The wine industry now recognises that the grape growers play at least as important a role in the making of wine as the winemakers. We have been slower than the rest of the world to catch on to the idea, but the major quality advances in Australian wine will take place in the vineyard. While modern winemaking can turn even the most appalling fruit into something drinkable, it is impossible to make world-class wine from poor fruit. This is one of the reasons why vineyard management is so important. Bulk wines, and to a lesser extent commercially-priced bottled wines, can be made from indifferent fruit, whereas premium wines with flair, character and complexity cannot. It will come as no surprise then, that vineyards established to produce bulk wines, and those designed for up-market styles are handled differently by their managers. The Species of Grapevines The vine species responsible for all wine made around the world with the small exception of some American wines, is Vitis vinifera. This species also accounts for the majority of table grapes harvested in all countries except the United States. There are four native American species of grapevine whose characteristics of flavour, structure and growth differ markedly from vinifera. These are Vitis labrusca, Vitis rotundifolia, Vitis rupestris and Vitis riparia. Some of these are used in winemaking and table grape production in the United States. They are used as rootstocks for many modern vines grown in all winemaking countries for their resistance to disease, salinity and other soil conditions. The Vitis vinifera species includes all the major grape varieties used in wine production, including cabernet sauvignon, chardonnay, riesling, sauvignon blanc and pinot noir. It also includes sultana, known around the world as Thompson Seedless. Origins of Viticulture Modern viticulture aims to control the growth of the vine to produce the best crop of healthy fruit in the given set of natural circumstances provided by soil, climate and site exposure. Consideration needs to be given of the optimal yield a vine should produce, for it is not necessarily so that the biggest crop is the most suitable. In many cases the best quality fruit is achieved through small yields. Yields can vary either naturally or through human intervention. The ancient vineyards were fields of vines without any trellising, which spread out octopus-fashion over the land. Since the fruit grew at ground level, disease was rampant and management was impossible. Early attempts at viticulture just lifted the whole vines off the ground with small stakes. The Romans introduced elm trees to train their vines upwards, but these proved difficult to manage. The traditional European trellis systems, which we have now refined, restricted growth and encouraged fruitfulness. Modern Innovations Modern trellising and vineyard management systems attempt to balance the ‘vigour’ of the vineyard with yield and quality. In effect, this means that in high-yielding areas of average quality the trellis and pruning system will allow large vine canopy development and potential fruitfulness. In high-quality, low-yield areas the trellis is designed to maximise the fruit exposure and ripening potential of the smaller crop. Dense vine canopies create more humidity and produce excessive shade, which slows down ripening. Humidity encourages vine disease. Modern foliar sprays designed to protect the vines against insects and mould, and possibly to fertilise the vines, are more effective with a less-dense canopy, seeing they can penetrate further. How Fruit Ripens and Affects Wine Grapes accumulate sugar as a result of photosynthesis in the vines’ leaves, which is then translocated to the grapes themselves, as their ripeness increases. The Baume is an indirect index of sugar concentration used in wine. If juice contains enough sugar to produce a wine of 10% alcohol by volume when fully fermented to dryness, or a complete absence of sugar, its sugar concentration at that time is measured at 10o Baume. Most grapes are harvested between 11-13.5o Baume. Early-picked wines tend to be leaner, with less obvious fruit flavour, but with higher levels of natural acidity. They tend to live for a long time as bottled wines. Wines made from well-ripened fruit can be fuller, portier and possibly jammy. They are more strongly alcoholic wines, with a warmer feel in the mouth. Flavour does not have to be correlated with ripeness and the flavour build-up in grapes varies considerably between regions and grape varieties, and does not necessarily increase in proportion to the rate of ripening. The best wines in future will probably come from areas which can achieve the most intense and complex flavours at the desired degree of ripeness for the wine to be made. Pruning Pruning regulates yield and vigour, for the following year’s crop develops from the buds produced from this year’s growth. In this way, the number of buds the grower leaves after pruning regulates the following year’s crop. Whether pruning is light or severe will depend on the quality of the anticipated fruit, and if the vineyard can support the demands of a large vine as it endeavours to ripen all the fruit it produces. Top-quality wines come from more heavily-pruned vineyards which will ripen a smaller crop and support less foliage. Mechanical and minimal pruning techniques have been introduced in some quality-wine areas, especially in Coonawarra, South Australia. It is too early to say whether or not these techniques, which involve leaving an infinitely-higher number of buds on the vine, are able to maintain wine quality or not. Their advantage in reducing labour costs is obvious. Training The training of the vines is becoming more scientific with each passing season. In cool regions where every ray of sunlight must be exploited to its fullest potential, vines are hedged, in narrow vertical canopies which resemble vertical solar panel, which in actual fact they are. Where frosts are a danger, the vines are trellised high above the ground and the low temperatures there. But if the grower wishes to receive maximum re-reflected heat from the soil, the vines are grown low, near the soil surface. Trellises must avoid over-shading, which results in low grape acidity, and over-dense canopies, which encourage humidity and disease. Good air circulation is essential for quality fruit. Soils The effect that soils have on wine is largely indirect. Drainage and heat-storage capacity, for example, are two areas in which soils can directly affect the metabolism and performance of the vine, but which may or may not affect wine quality. Soil structure is very important from the physical point of view of farming the land with mechanical implements, for boggy soils may impede work during winter. Soil acidity, alkalinity or excessive wetness affects the rate of uptake of soil nutrients by the vine. Today where deficiencies exist in soil they may be replaced. Where soils are thin and unmanageable they can be worked and modified to suit the grower’s requirements. Significant soil management can be, however, extremely expensive. Seasonal Variation and Fruit Quality Wine from the same vineyard can vary dramatically from year to year. Hot years may increase depth of colour, but reduce purple colouring in red wine. Wet seasons produce wines of poorer, thinner structure. Top fruit is required to make top wine, which is the limiting factor to final wine quality. Good fruit must be healthy and free from unwanted disease, well-ripened and show the potential to become the style of wine the maker is after. The quality of the grape variety is important, and has a large say in the eventual quality of the wine. Lesson Five will discuss the different varieties and their qualities. What is regarded as good fruit, and what is not, may change with time. Eden Valley Rhine Riesling is a clear example. In the 1960s and early 1970s, these wines were made from relatively green and unripe fruit which retained a high level of natural acidity. They were not particularly attractive young wines, and really needed cellaring time to fill out and become ready to drink, and to grow out of the ‘steeliness’ of their youth. Because there has been a strong trend over recent years to market wine that does not require cellaring, because few people today can afford to maintain a cellar, the Eden Valley Rhine Rieslings of today are richer, riper young wines that are much more approachable when young. Cool and Warm Climates Cool climates firstly retard the ripening of the berry, then allow it to finish ripening after the summer’s heat has passed, in the less-searing months of autumn. Some Victorian and Tasmanian vineyards harvest as late as May, and April picking is a common sight in the southern wine regions. Cooler climates retain more of the delicate grape flavours than would otherwise be experienced if the same vine grew and ripened fruit in a warmer location. It is the period between budburst and flowering in the spring that is sensitive to temperature and is retarded by cool climates. This is what pushes the whole ripening phase back later into the year, into a yet cooler period – which has an effect on the fruit composition and is directly responsible for the ‘cool climate’ character of more intense fruit flavours and desirably higher levels of natural acidity. Micro, Macro and Meso-Climates There is a great deal of confusion about these terms, judging from what is written in the media and what is mentioned in wine conversation. A ‘macro’ climate refers to an entire wine region, eg the Yarra Valley. A ‘meso’ climate refers to a particular slope or topographic form within a region, eg a slope running down from the Maroondah Highway at St Huberts, in the Yarra Valley. The ‘micro’ climate refers to the particular conditions of humidity, temperature and shade within a particular canopy in a row of vines in a particular site. Therefore, if we describe a canopy within a row on that particular slope at St Huberts, we are referring to a microclimate. Anyone who mentions a ‘microclimate’ of a region, or even a winery, is talking nonsense! Phylloxera Phylloxera vastatrix is a parasitic vine disease, which is a burrowing plant louse of the Aphididae family, indigenous to the native vines of North America. In the second half of the eighteenth century phylloxera caused considerable damage to the Californian vineyards and was unwittingly transported to Europe on vine-cuttings. There it devastated most of the vineyards of the wine-producing countries. The only reliable remedy for the disease is to graft vines onto the resistant North American rootstocks of Vitis labrusca and Vitis rupestris. Phylloxera arrived in Australia after Europe, but was in part responsible for the decline of the early Victorian wine industry. But phylloxera is to some degree unfairly blamed for playing a greater role than it did in the disintegration of Victoria’s wine industry last century. It arrived at Geelong in 1875 and moved north-east towards the Goulburn Valley and Rutherglen. It is still to be seen in some vineyards in the Goulburn River and North-East Victoria. Phylloxera never touched the Yarra Valley, whose decline over the latter years of last century and up to the first World War, was purely economic. As Francois De Castella put it, ‘The Yarra fell to the cow’. Simply put, the valley was making far too much wine of a kind only suited to export markets such as those in the UK and USA. The upper echelons of Australian society thought ‘colonial wine’ was beneath them, so when the export markets crashed in the global depression, the Yarra had nowhere to sell its wine. The Yearly Vineyard Cycle The vigneron’s calendar begins each spring when the sap begins to flow inside the vines, heralding the end of the winter dormancy. The brown sheaths on the buds fall off and the buds burst. Throughout spring the vegetative growth of the vine continues and the flowers form and are fertilised, causing the berries to set. This period of time is used by the grower to spray the vines against diseases, monitor weed competition and to guard against early frosts which could destroy the year’s crop if the young buds and shoots are damaged. Summer is the period of berry growth, during which they swell and accumulate acid, then sugar. In the later stages of ripening the grapes become less acidic and more sweet. They are harvested when they attain a sugar level sufficient to make a wine if between eleven and fourteen percent alcohol by volume, depending on the style of wine required. Throughout the ripening period the grower will continually spray the vines with select chemicals to control pests and diseases. Each of these chemicals has a designated period of time after which they have been broken down and are ineffective. Growers must not harvest until that period has been reached. Weed control throughout ripening is also important to ensure that all the vineyard’s growing potential is directed towards fruit growth. Extra and unwanted vine canopy may be trimmed back to ensure the best fruit exposure and also to reduce competition for the fruit. The vintage takes place from early to late February, depending on the region. Warm regions with more sunshine ripen and are harvested earlier than cooler climates. White grapes may be left to be late-harvested to accumulate more sugar for sweet late-picked dessert wines. During winter the vines fall dormant and the grower will prune the vineyards. Other general maintenance and fertilisation of the vineyard will take place throughout winter.
