Viticulture 1: what is viticulture?

What is viticulture? Viticulture is the science (or art?) of growing vines - cultivation (-culture) of Vitis Vinifera (viti-), the wine grape as it's known in botany speak. This is one of the three most important aspects of wine, along with tasting and vinification. The reason is simple enough - imagine you understand how grapes are grown, you know how wine can be made and you can taste. Then, to understand Bordeaux, for example, you need only be told the soil, climate and weather conditions, any unusual vinification practices and Hey presto! you can figure out how the wines should taste. It ain't quite that simple in real life but a thorough knowledge of the cornerstones helps you to better understand regions as you study them.

There are a number of aspects to viticulture which are important, including the vine, grapes, soil, climate, topography, pests and diseases and these will all be covered briefly. Bear in mind that this subject if far too complex for a short online series to fully explain but a lot of the basics are easy to understand.

Viticulture 2: the vine

The vine is a climbing plant, not unlike ivy. It can cling to any structure as it grows upwards and can grow wild very easily. If it is in danger of dying it produces fruit, the grape, inside of which is one or more seeds, or pips. These contain all the genetic material required to produce a complete copy of the original vine and can, therefore, help to propagate the species.

Grapegrowers take advantage of these characteristics by pruning and training the vine so that it produces fruit every year. The vine's climbing ability is rarely relied upon nowadays but, in ancient times, vines were trained up trees or onto pergolas in order to facilitate vineyard work - a practice dying out but still evident today. Below ground, the vine's roots collect nutrients (only down to 80 - 100 cm of soil depth) and water and these are transported though the trunk to the leaves. Here, in the presence of chlorophyll heat and light from the sun are trapped with carbon dioxide (CO₂) to form starch. This is used as energy for growth but excess is stored as sugar in the grape - which is then converted to alcohol in fermentation.

Viticulture 3: the vineyard

Viticulture 4: climate

Climate is weather aggregated over a large period of time. So, for example, a very cold winter does not mean the climate is not warming up as two months of weather pales into 50 years or more of climate. In the vineyard the climate is crucial to the health and flavour of the grapes and, therefore,  also to the quality of the final wine. Light and heat are essential for photosynthesis, the process whereby energy, water and CO₂ are converted to starch. However, as in all things, moderation is ideal - too much heat can cause the vine to dehydrate and so actually stop the grapes from ripening; too little leaves the fruit tasting green and tart.

Grapegrowers consider three types of climate: macro- (essentially the weather in a large area), meso- (climate in a small area such as a village or collection of vineyards) and micro-climate (climate around the vine itself). Cool macro-climates tend to produce acidic wines, usually white, hot climates tend to produce soft fruity red wines. all in all, the effect of climate on a wine's flavour is one of the easiest things for tasters of all levels to spot and, apart from the grape itself, is perhaps the most obvious taste factor to spot.

Viticulture 5: soil

Soil is vital to the vine's survival as all the vine's nutritional needs (water and various minerals etc.) are all found in the soil. Soils which, in any way, impinge adversely on the vine's ability to nourish itself can have a disastrous impact on wine quality. However, while soil can affect wine flavour it is typically in an indirect way - unlike climate which is more obvious in that it affects how flavours develop in the grape as it ripens.

Generally, vines like moderately warm, moderately wet soils although this is a gross generalisation. Some grape varieties really need dry soils (mourvedre, for example, or even syrah), others can do well in wet or fertile soils (surprisingly the vigorous carmenere actually does best on vigorous soils). One way or another the grapegrower wans the vine to get just the right amount of water - too much and the grapes are dilute and so, then, is the wine; too little and there's not enough juice for wine! In the wet regions of Europe this balance was achieved naturally by planting on hillsides but in the drier, flatter new world vineyards tend to be irrigated.

Viticulture 6: topography

Topography is the shape of the land and it is important in that it enables vines to grow and ripen fruit in areas which might otherwise prove tricky. Consider Burgundy and, in particular, the famous golden slopes of the Cote d'Or. For those who have never seen it this is an escarpment, about 150 - 200 m in height, which runs in a north-east to south-westerly direction from Dijon, past Beaune and onto Santenay. Below and above the escarpment is flat land, mostly agricultural and unsuited for grape growing. Why? Because here the climate is quite wet and light and heat are at a premium so ripening is tricky and vigour can be high.

However, the slope makes a big difference. First, soil water drains down the slope leaving the vineyard soils usually adequately watered, but not too much. Second, the slope exposes more of the vineyard to light and heat and so encourages better ripening. It is notable that the finest sites in Burgundy are, more or less, mid-slope where vineyard soil depth is greatest and where light and heat interception is optimum. In other areas topography can ameliorate other problems - in South Africa, for example, upper slopes facing south are the coolest spots and, therefore, best for white grapes.

Viticulture 7: pests and diseases

There are many pests and diseases which can affect the vine. Some can be fatal (Pierce's disease, for example), some simply cause the vine to weaken or interrupt the process of photosynthesis thereby affect fruit quality. Some (e.g. boars) just cause damage leaving vines weakened or, frequently, so damaged they have to be grubbed up. By the way, that's "boar" the animal and not "bore" the wine buff!

Diseases fall into two main categories - fungal and viral. Fungal diseases are rot and mildew, well known to gardeners everywhere. Until the mid 19th century most European vines suffered from little or no disease pressure but the importation of vines from America brought two major diseases: downy and powdery mildew. These attack the leaves of the vine and so cause a deterioration of fruit quality. Among the rots is the two-faced botrytis which, as grey rot destroys grapes but as noble rot simply dehydrates them slowly allowing superb sweet wines such as Sauternes to be made. Viruses usually kill the vine, slowly, and adversely affect fruit quality by causing damage to leaves. Pests include birds (they damage grapes), mites and spiders (often controlled by using other insects which feed on them) and phylloxera.

Viticulture 8: phylloxera

Viticulture 9: vigour

Viticulture 10: canopy management

Canopy management is an aspect of viticulture that became trendy some 20 years ago, even though it's as old as grapegrowing. The canopy is the layer of leaves which grow from the vine. Too many causes shading, too few leaves the vine underperforming. Knowing how to shape the vine's canopy can help solve a lot of wine quality problems. It's trendy because Dr Richard Smart wrote an extremely useful book called "Sunlight into wine" which set out logical principles for canopy management. His ideas showed that in some regions, such as Bordeaux, low hedges of vines, closely planted is an optimum solution to the local conditions but that this would not necessarily work everywhere. 

The canopy is shaped to do two things - reduce shading and control vigour. Shading is reduced by shaping the vine in such a way as to ensure that there are only two, maybe three leaves, in the canopy depth. Vigour is controlled by ensuring there is a proper balance between the number of buds on the vine and the vigour of the soil. Properly managed canopies result in balanced growth and optimally ripe fruit; improperly managed canopies lead to shading, poor fruit quality and issues with yield.