Grape harvesting machines: use and distribution
Grape harvesting is still carried out mainly by hand, both in the case of wine grapes and table grapes. The mechanization of the harvest of wine grapes, with the use of grape harvesters, has entered a new phase of application, however some regulations on the means of production of wines with denomination of origin do not currently allow the use of mechanical means: l Grapes that are brought to the cellar must be intact before undergoing any processing. Other regulations foresee the carrying out of the collection in three phases or subsequent sorting. If it is true that the legitimate search for a lower production cost by winegrowers is a good reason to rely on mechanical harvesting, it is also true that there are other factors to consider. The number of elements involved with this new technique is so high that it cannot be assumed that the use of these machines cannot have effects on the nature of the product.
Mechanical harvesting with horizontal and vertical shaking
The mechanical harvest for horizontal shaking can be used in vineyards with counter-espalier cultivation (Guyot, Casarsa, etc.), with maximum slopes of the land of 15-20% and with planting distances suitable for the passage of grape harvesting machines. The latter are of various sizes and, therefore, have different needs in terms of space: some small inter-row vehicles require a distance between the rows of at least 2.5 meters, while some large models require at least 3.5 meters). The mechanical harvest by vertical shaking, on the other hand, is applicable only in vineyards with suitable training methods (G.D.C., Duplex). These tools are equipped with a beater that strikes, quickly, the wire that supports the permanent cord of the screw. The high beating frequency allows the berries to detach from the pedicel and fall into special bins. Even these machines, like the previous ones, can be self-propelled, towed or carried by the tractor and act on either the row or the inter-row. In the world, horizontal shaking prevails almost absolutely.
The characteristics of work in mechanical harvesting
Mechanical machinery operates with a working capacity ranging from 0.3 to 0.5 hectares per hour, with product losses fluctuating between 7 and 15%. These last data, therefore, are widely tolerable in table wines, less so in fine wines. From an economic point of view, it is believed that, especially in the Italian context, the convenience of mechanical harvesting can be directed towards medium-small, inter-row models, pulled or carried by tractors, which can also be used for other cultural operations. In recent years, however, significant progress has been made in the development of harvesting technologies, making the machines more suitable for facing difficult situations and elements of piling (in particular the widespread cement pole) not particularly suitable for this practice. Moreover, like every other sector of daily life, even that of these machines has been affected by the ever deeper application of electronics.
Grape harvesting machines: Grape harvesters in Italy and France: two situations compared
The existing grape harvesters in France are now several thousand (industry estimates speak of 15,000 pieces). In 1981 the maximum sales were reached with 1,353 models, while in 1993 746 machines were sold. Currently there is a certain market fatigue. However, it should be noted that the French market is quite saturated. For example, in the Charente (Cognac) and in the Gers (Armagnac) almost 100% of the surface is harvested by machine; in the Loire Valley and in the Gironde (Bordeaux) more than 80% of the vineyards are harvested by machine. By contrast, in Italy these instruments are only a few thousand, around 2,000 trailed and self-propelled. Furthermore, the analysis of the Italian market is difficult due to the problems and delays of the bureaucracy for the allocation of contributions. In fact, the market freezes because everyone thinks they can access contributions, while these are not granted.