The Vine

The grapevine Vitis vinifera, originally native to East Asia, is now the most commonly cultivated species across the world. Within the vinifera species are thousands of varieties, possibly as many as 10,000, although few of them are used to make wine. Only 200 are recorded as being significant in France.

The varieties commonly used for winemaking have developed over the centuries. Sometimes they have appeared naturally, sometimes encouraged by grape growers. The pinot family, for instance, is prone to mutation. Pinot meunier and pinot gris came from pinot noir, pinot blanc from pinot gris.

For the last century or so, it has been possible to create specific new varieties by taking the pollen from one and fertilizing the flower of another variety, and planting out the resulting seeds. The two most famous of these crossings are probably maller-thurgau, now the most widely planted grape in Germany, and pinotage in South Africa. Both will occasionally make good wine, but they are generally used as workhorse varieties. The problem with new varieties is that the viticulturists who produce them are searching for higher yields or early ripening rather than enhanced flavor, structure or quality in the resulting wine.

It is now also possible to produce hybrids-vines that have as their parents both a Vitis vinifera vine and another species, invariably one from North America. This is done to create vines with resistance to specific pests, diseases or weather conditions. Traditionally, hybrids are perceived to make poor wine and are prohibited for the production of "quality" wine in Europe. In practice, some of these grapes-seyval blanc in the United Kingdom is an example-can make fair, if not great, wine.

Most viticultural attention these days is focused not on new varieties, but on the genetic manipulation of existing varieties. It should be possible to exclude from Chardonnay the genes that make it prone to rots and other fungal diseases, thus reducing the costs of growing the grapes and guaranteeing more regular quality. Inevitably, this raises the specter of labeling problems, with consumers seeking information about genetically manipulated wine. Less acknowledged is the likelihood that, as with most other viticultural developments, modifications will be developed to aid the grape grower-primarily by encouraging larger yields-rather than the consumer, who would rather see the development of more intense, complex and harmonious wines.

The most important part of the vine's cycle is the process of ripening, which is what creates the final wine-and it is particularly important in the period following viraison (the key stage at which the grape skins begin to turn black, or to become translucent if they are white grapes). After viraison, when the vine normally has sufficient reserves of sugar, the surplus is sent into the grapes. This is eventually converted to alcohol, making grape juice into wine.

Ripening, however, is crucial for more than just sugar accumulation. The acidity is very high in developing grapes, but'the relative acid levels drop with the ripening process, allowing a balanced wine to develop. In cool grape-growing regions, poor weather during summer can limit ripening. If this happens, the resulting wines will be unbalanced or will have to be treated to reduce the acidity. Conversely, in hot regions, the acidity may drop too much and have to be replaced.

Ripening also allows the various flavor components of the grape to develop. At the same time, the phenolic compounds that give red wines their color and tannin also increase, with the tannins developing from green and coarse to ripe and smooth. Red wine made from insufficiently ripened grapes will be found to have a harsh, bitter, tannic structure.