Winemaking is broken down into two broad categories that distinguish different phases of the total process. These are viticulture, the growing of the grapes and vinification which is the turning of the grapes into wine.
The grape vine is a member of the Ampelidacceae family. The grape is the fruit of that vine. The Vitis section of that family is split into many differnt branches. The vitis vinifera branch is the main branch that we will be concerned with. Literally the "wine vine" 99% of all wines consumed come from this branch. Familiar members of this family include Chardonnay Cabernet Sauvignon, Riesling and others.
The confusing origins of this vine are really clear. The current evidence suggests that over many thousands of years it evolved from wild vines growing in Central Asia. During this time literally thousands of recognisably distinct varieties have developed, each with their own traits to contribute to production from a vineyard in some part of the world.
Other members of the Vitas section have played a role in winemaking. Vitas labrusca is used for winemaking in New York State, Madeira and Russia, vitas riparia and vitas rupretis have their root stock grafted with vita vinifera scions in order to protect from phylloxera. Wine which is made from these other varieties tend to have an unpleasant flavour (usually bitter after taste) called "foxy".
Vine Development
The phylloxera aphid, attacked vinifera grape vines across europe during the second half of the 19th century. It became so bad that frowers had to find alternative vines to produce grapes with.
Vitas labrusca vines were tried because they were resistant to the aphid but was eventually abandoned because of the foxy taste left in the finished wines.
Hybrids
The next attempt to solve the problem involved the crossing aphid resistant American vines with vinifera ones. This involved taking pollen from an american vine and polinating a vinifera one and then planting the resultant seeds.
There have been some individual successes such as the high yielding Noah grape or the cool climate ripening ability of Seyval Blanc but in most cases the foxy taste was not removed.
In the European Community no quality wine can be made from these grapes for this reason. This doesn't mean however, that there isn't a role for hybrids in more marginal wine growing areas where extra care csn be tasken to produce excellent wines (ie Baco Noir in Ontario).
It was eventually discovered that vinfera vines could be grafted onto American root stocks and thus protect it from phylloxera.
Clones
Cuttings are taken from individually selected vines for their certain characteristics (ie disease resistance, early ripening, high yields, finese, colour etc). These cuttings are grafted and planted and assesed further. This process may accur for several generations. It is then commercially propogated to maintain fidelity.
Crossings
This is simply the cross pollination of one vitas vinifera to another. Examples of this are Germany's Muller-Thurgau and Scheurbe for cool climates which are now extensively planted their and the University of California Davis campus development of Centurion and Emerald Riesling for hot climates. Cloning was a parallel development with cloning.
Grafting
There are large areas of California, Chile, Hungary, South Australia, and other areas where grafting is not essential to crop survival most vineyards use grafting anyways to prevent any future phylloxera infestation. Each vine has two parts, an American rootstock with a scion vitas vinifera grafted onto it. The choice of rootstock is just as important as the scion, for it has to be adapted to the soil and the climate of the vineyard and to the vinifera variety. Each region will have it's preffered rootstocks. Major vineyards will have their own nursuries where vine propogation is carried out.
Selection of Grape Varieties
There are more than a thousand varieties of grapes used to make wine but most have only local relevance. A number have a global reputation because they are either grown around the world or they are a major constituent of a classic wine.
Most of the traditional European wine producing regions select their grapes to be grown by law and by tradition. In some cases this has led to great wines being produced from non traditional varieties and being classified at the lowest levels of the wine hierarchy. An example of this is in Tuscany where Cabernet Sauvignon was introduced and very expensive vini da tavola resulted.
Wine laws are once in a while changed to accommodate these wines.
The characteristics of the vines themselves are often the baisis for selection. The annual cycle of a vine's growth will vary slightly from one variety to another. Certain varieties will bud later than most, some will ripen earlier or later than others. Different vine varieties are, therefore suited to different sites, For example, in the frost-prone Marne valley in the Champagne region, the Pinot Meunier variety is preferred as it buds a few days later than Pinot Noir, making it less susceptible to spring frosts. In Germany Riesling produces the best wines but somtimes ripens so late that the crop is spoiled by autumn weather; in order to guarantee a harvest many growers have planted the earlier ripening Muller-Thurgau.
Other countries have less strigent regulations for grape selection . In the USA for example, in California it isn't strange to see a number of varieties of different regions, soils and climates native to France growing side by side.
1500 hours of sunshine is usually the minimum requirement for grapes to ripen stisfactorily. Rewd grapes need more heat and sinshine to fully ripen than whites. This is why most marginal vineyard areas such as in Germany and Britain which lie close to the limits of vineyard cultivation are planted with more white varieties and early ripening reds.
A vine also needs considerable water amounts of water to grow satisfactorily, usually about 700 mm of rain a year but cooler regions may exist on less. In countries outside the EC irrigation may be used to supplement the lack of rain. With the exception of young vines and experimental vineyards, this is not permitted within the EC.
Commercial vineyards are concentrated in two broad bands in the northern and southern hemispheres, approximatelty between 30 and 50 degrees latitude. Wild vines grow throughout the world. It's in these latitudes that there is the proper balance of heat, cold, sunshine and rainfall to allow for the best growing conditions for the vine and ripening of the fruit. North and south of these bands it is too cold for fruit ripening. Between them there is no cold season to allow the vines to rest. Factors other than latitude also affect the climate, allowing vineyards to beplanted in the UK at latitudes of 51N or in subtropical parts of South America.
Conditions of climate can be classified in a number of ways. Two are used in the European Community. The cooler northern vineyards of Britain and most of Germany being in Zone A and those in southern Europe being classed as Zone CIIIb. Permitted must treatments vary according to the zone. For example in Zone A the alchoholic content of a wine may, in poor years be increased by up to 4.5% by chaptilisation and the wines can be de-acified.
This comapres with southern Italy (ZoneCIIIb) tartaric acid may be added but de-acidification and chaptilisation are forbidden. Zones A and B are not subdivided; Zone C is divided into five, designated Cla, Clb, CIIIa and CIIIb, allowing finer definition of the rules.
Originated by the University California Davis many New World regions use the degree-day system to classify climate. The system works on the principle of heat summation , where the average daily temperature is multiplied by the number of days in the growing season (April to October in the northern hemisphere), giving a figure that allows different regions to be compared. Only temperatures of 10C or higher are considered since the vine doesn't grow at temperatures below this.
Both systems have their uses in comparing one region with another however, neither takes all climatic factors into account thus cannot totaly define the climate of a region.
Climates will be moderated if close to large bodies of water (ie Lake Ontario and Lake Erie for the Niagara Penninsula or Bordeaux near the Atlantic Ocean). Bordeaux has a maritime climate of warm summers and cool winters, less extreme than the harsher continental climate of extremely hot summers and very cold winters experienced by landlocked vineyards of La Mancha in central Spain.
In winter and spring rivers help reduce the damage caused by frost as the movement of water keeps the surrounding air moving. Water will increase the humidity and thereby can help create the ideal conditions for noble rot, the essential factor in the production of the finest sweet light wines.
Climate is affected by topography and altitude. Mountains can be the source of cold winds like the Mistral that blows through the Rhone valley. The temperature drops with increasing altitude , so vineyards planted at high altitudes will be cooler than the latitude might indicate.
Individual vineyard sites have their own climate conditions even though a region will have an overall climate. Individual vineyard climates can vary from location to location. A particular vineyard might have a micro climate suitable for the production of higher quality wine than a neighbouring one.
It's essential that vines recieve the maximum sunshine during a growing period in more marginal growing regions. The individual contours of a slope can have a significant affect by increasing the vines exposure to the sun. In areas of the extreme northern boundary of cultivation the aspect of a vineyard can increase the exposure and thereby significantly improve the ripeness of the resulting grapes. An example of this is the Mosel valley where the best vineyards are planted on very steep south facing slopes.
An important role may be played by prevailing winds either favourably or unfavourably. Mountain ranges or forests protect many fine vineyards that would not exist otherwise.
The concept of soil composition playing a role in the quality of a wine made is coming more to the fore front. In a general context it can be argued that certain grapes seem to be suited to certain soils. The most important issue is that the soil drains well. Poor wines come from vines with damp feet.
Vines which have to fight to survive often produce the best wines. When planted in poor soil, vines send their roots deep into the subsoil to find water and nutrients, collecting minerals and trace elements and thus improving the quality of the grape. Vines planted in rich soil tend to have their roots grow laterally finding fewer minerals. Also there is a tendancy for vines to over crop in rich soils which also dilutes the quality of fruit. Soils that are unfit to support other crops often become the location of vineyards
The French have a term (Terroir,) that is used to describe a happy three way marriage of soil, climate and grape variety which combine to produce classic wines. For example, gravel, temperate maritime conditions and the Cabernet Sauvignon grape combine to produce the great wines of the Medoc , whereas Gamay is associated with a warm climate and granite in Beaujolais, and Riesling with slate in the cool vineyards of the Mosel.
A lot of New World viticulyuralists believe that soil is of less importance than their European counterparts believe, Their theory being that , provided the soil is well drained , it's composition does not affect the style of the wine.
Planting
Vines are planted to either,establish new vineyards or to replace old vines. Overproduction in the EC tends to make new vineyard starts to be less common.
The life of a vine can be long. Century old vines are still producing in California, Australia, and the Muscadet region. In general, the older the vine the finer the wine that can be made from it. The tradeoff to this is a drop in crop yield. Since the aim of the grower is to make a profit, a balance has to be struck between quantity and quality produced. The grower has to determine the optimum age as to when he will pull up his vine . In general this happens between 35 and 50 years old. Normally the replanting program will be rotated so as to have the domain stillin production. Often the land will be left fallow for three years or so, and this has to be taken into consideration.
Tradition and legislation have played a large part in how a vineyard is planted in Western Europe, though there are a number of local factors that might have to be taken into consideration. These might include the steepness of the plot on which the vines are being planted, the form of pruning that is to be used , whether the vineyard is to be cultivated mechanically or not and whether the grapes are to be picked by hand or machine.
The soil has to prepared to a fine tilth before young vines are planted. Black plastic sheeting is placed on the ground around the vine to protect it from weeds. Individual guards may also be placed around the vine to protect it from animals. The first crop usually comes to fruit in the third year. Many jurisdications however prohibit the use of this crop for wine production.
The density of the planting might vary from three thousand vines per hectare, up to ten thousand or more. Apart from the factors listed above this decision will be based on how how much stress the grower wants to place upon the vines; the theory being the more vines per hectare, the greater the stress, the better the wine that is produced. As fewer vines have to be bought and planted, low density planting is initially cheaper.
The vines shape will be governed by the way in which the vine grower prunes and trains it, once it is established. Every vine has certain distinct parts; roots, trunk, cane/spur shoots, flowers/fruit and leaves.
The vinifera scion which, in time forms the vines trunk, is the visible part of the vine, with the graft usually just above the ground level. Shoots, bearing tendrils and leaves grow from the scion. These shoots will mature and become orange-brown over the course of the following winter, at which point they are called canes. Buds will form where the previous season's leaves joined the cane, and these are the source of the new shoots. A cane will have between eight and fifteen buds, each of which will form a shoot. The vine's flowers , and therefore fruit , will develop on shoots formed in the spring of the same year. I a cane is pruned short , to only two or three buds, it is referred to as a spur. by the end of the next year the cane and spurs are old wood and are often removed at pruning, with new replacement canes or spurs having been allowed to grow.
There is a long period of disruption when a vineyard is replanted,during which grapes cannot be produced. Head-grafting is becoming more popular in New World vineyards to reduce the financial burden of this. This is when the variety of a vine can be changed by regrafting onto mature vines in the vineyards. This makes it easier for the producer to react quickly to the demands of the market.
Pruning
The way in which the vine will be pruned and trained is an integral part of the legislation for most quality wine areas in Europe. The object of the main, winter, pruning is generally twofold: to select the buds that will form shoots for the production of fruit in this particular harvest, and to prpare the vine for fruiting in future harvests. Pruning will also be used to restrict or optimize the final yield by controlling the number of buds, and therefore the potential quantity , and therefore quantity , of fruit produced. Further roles of pruning throughout the growing season might be:
the restriction of vegetation, to concentrate the vigour of the vine into production of fruit;
to control the leaf canopy so that the bunches of grapes have the optimum exposure to (or shade from) the sun, and aeration to limit potential fungal infections;
to keep the vineyard tidy to ease work throughout the growing season and vintage.
As part of their legislation most quality wine regions will have minimum yield figures. For example , in Alsace , the base figure for Pinot Noir is 80 hectolitres of wine per hectare (hl/ha), while in Romanee-Conti in Burgundy, the equivalent figure is 35hl/ha. The differance in yields will be reflected in the fruit concentration, and therefore relative quality, of the two wines. By leaving fewer buds on the canes the Burgundian grower will restrict the number of shoots and therefore the number of bunches of grapes produced.
There are two basic types of pruning :spur, in which a number of short, two to three bud spurs are left on the vine, and cane, wwhere one or two longer canes, each of eight to twelve buds are left.
Factors such as the climate, the vineyard and the yield required means that the training of the vine can vary greatly. Vines may be trained low to benefit from reflected heat from the ground or to avoid wind damage. They may be grown high, away from reflected heat from the ground. This also has the advantage of increasing the air circulation and minimising rot in humid conditions.
There are three main systems for traing vines.
1. The bush system, with it's common variation the goblet. This spur-pruned system is used in warmer vineyard regions such as those of Beaujolais the Rhone Valley, the South of France and Spain. As air circulation is poor, this is not suitable for damp vineyard regions, where rot may be a problem, nor is it adviseable for areas which suffer from spring frosts as the vines are close to the ground. The vines are free-standing and there are normally four to five spurs left around the head of the vine trunk. in the goblet system, the shoots are tied together at their tips.
2. The replacement cane system, which includes the Guyot, as practised in Burgundy and Bordeaux. Here canes are trained along lateral wires, with new producing canes: one in the case of Guyot simple, two in the case of Guyot double.
3. The cordon spur system is most often used invineyards fully adapted for mechanisation. The trunk of the vine is developed horizontally, with a number of spurs left along it's length. This may be a low cordon, as in the Cordon de Royat system in Champagne, or high, as in the geneva Double curtain system.