Every drop of wine you drink is rain recovered from the ground by the mechanism of the plant that bears grapes, the vine. For the first three to four years of its life, a young vine is too busy creating a root system and building a strong woody stalk to bear more than a few grapes.
Better quality grapes grow on a vine that is regularly cut back to a very limited number of buds. The annual pruning is done in mid-winter, when the dormant plant will lose the least sap from its wounds. As a vine grows older, its principal roots penetrate deeper into the ground. While it is young and near the surface, they are vulnerable to drought and floods. A vine is in its prime from 12 to about 40 years old. Therefore, a very young vine planted on the mountain slopes of Napa Valley will not fetch the higher price of the much more mature vines. Although there are no strict laws in place to regulate the use of the term, the French often use vieilles vignes, which translates to "old vines" to assure the consumer that the wine was produced from the most mature vines in the vineyards. The same is true for the use of "old vine" on the label in California.
The best soils drain quickly and deeply, drawing the roots down to greater depths to find a stable water supply. At the same time, the vine constantly grows new feeder roots near the surface.
There are basic parts to every vine. The vitus vinifera scion, which in time forms the vine's trunk, is the visible part of the vine with the graft usually just above ground. Shoots grow from the scion. These shoots will mature over the course of winter and become canes. A cane will have between 8 and 15 buds, each of which will form a shoot. The vines' flowers, which later become fruit, will develop on shoots formed in the spring of the same year. If 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 canes and spurs are old wood and are often removed at pruning with new replacement canes or spurs having been allowed to grow.
The training of the vine, too, varies greatly according to such factors as the climate, the vineyard and the yield required. Vines may be trained low to benefit from reflected heat or to avoid wind damage. They may be grown high, away from the reflected heat from the ground. This also has the advantage of increasing the air circulation and minimizing rot in humid conditions. There are three basic systems currently in place for training vines:
- Bush system or head pruned
This spur-pruned system is used in the warmer vineyard regions such as those of Beaujolais, the Rhône, 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. It is also not advisable for areas which suffer from spring frosts, as the vines are too 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. (Common variation: gobelet) - Replacement cane system
This training system is includes the Guyot and is practiced in Burgundy and Bordeaux. Here, canes are trained along lateral wires with new producing canes being used each year: one in the case of Guyot single, two in the case of Guyot double. - Cordon spur system
This method is most often used in vineyards fully adapted for mechanization. The trunk of the wines is developed horizontally with a number of spurs left along its length.
