There are some that argue that no matter what you do in the winery, all great wine is made in the vineyard. Whether or not you believe this to be exactly true, one thing that cannot be argued is that two of the most vital steps in the winemaking process occur in the vineyard—pruning and training.
What is the Difference Between Pruning and Training?
Both pruning and training refer to the practice of removing selected plant parts in order to manipulate a grapevine into growing in a certain formation.
Training occurs at the beginning of a grapevine's life, in the first three to five years where the objective is to develop a strong, woody base plant. Thereafter, pruning is carried out on a yearly basis, with specific tasks that must be carried out at certain times in the growing season.
Or, to put it more simply: training is used to develop a grapevine while pruning is a form of maintenance.
Why is Grapevine Training Important?
In order for grapevines to produce high-quality wine grapes, they must first spend a few years developing a strong, wooden trunk, and a sprawling network of anchoring roots. Both will later play a vital role in receiving and storing water and nutrients, as well as stabilizing the plant through extreme weather conditions.
Winemaking would simply not be a sustainable business if grape growers had to replant and cultivate vines every year, not to mention the fact that it takes at least three years before grapevines produce fruit which is of a suitable quality for winemaking.
Types of Grapevine Training
If you've visited different vineyards, you may have noticed that not all grapevines look the same. This has nothing to do with the species of grapevine - nearly all grapes used in winemaking actually come from the same species: Vitis vinifera, and instead is an example of different methods of training. (Read on in "The History of Vitis Vinifera.")
While there are numerous training methods, each of which adapted for unique environments and conditions, the most common and important to learn are Guyot (cane) and Cordon (spur) techniques.
Without getting too technical, the main difference between the two types of training is that the 'arms' that protrude from the trunk on Cordon-trained vines are wooden and permanent, while those on Guyot-trained vines are only semi-permanent, with new ones selected for use every year.
In general, Cordon-trained vines are better adapted to warmer wine regions such as California and Spain, while Guyot-trained vines are more common in cooler regions such as Burgundy and Oregon and Washington.
Besides climate, other factors that might influence vine training and general vine management include the desired harvesting method; as well as the vineyard's resources of sunlight, temperature, nutrients and water.
Why is Pruning Important?
Left to their own devices, grapevines continue to grow and multiply to the maximum possible size that the supply of sunlight, water and nutrients allows.
The bigger the grapevine, the larger the crop of fruit it produces—which at first sounds like a good thing, right? Not quite.
The larger the volume of fruit in a crop, the lower the concentration of the individual grapes and therefore the weaker—and poorer quality—of the wine produced. Pruning, therefore, is vital in order to produce high quality, concentrated grapes.
As a form of maintenance, pruning is also essential for the removal of diseased parts of a plant, as well as for thinning and decreasing the concentration of leaves (or canopy), which can prevent grapes from receiving the sunlight they need, or create a humid environment promoting the development of Botrytis cinerea (grey rot).
When Does Pruning Take Place?
Pruning takes place throughout the year and the focus of the work changes, depending on the stage of the growing season.
Most important of all is winter pruning, particularly in Guyot-trained vines, where grape growers must make important decisions regarding which canes to choose for the following year's harvest.
Next, after buds begin to develop in Spring, growers must predict which are most likely to survive and produce the best grapes. Buds are fragile and susceptible to extreme weather conditions, therefore, a fine balance must be struck in pruning between not removing too many buds (in case of casualties during heavy weather) and not leaving too many, wasting vital energy and nutrients developing parts of the plant which will later be removed.
If these stages go well, the rest of the year's pruning is relatively straightforward. As the growing season approaches harvest, tasks include limiting the number of grape clusters to improve flavor and sugar concentration; as well as leaf or canopy management, to control the amount of sunlight grapes receive, as well as the humidity of their environment. If the canopy is left too thick, moisture can't evaporate and mold develops.
Vine training and pruning are two of the most important tools in a grape grower's arsenal. While there are numerous forms of training and multiple pruning decisions to make throughout the year, the overall goal is always the same: produce the maximum quantity of grapes of a determined quality, in the most effective (and economical) manner possible.
