Manual of techniques for sustainable mountain viticulture Josep Lluís Pérez Verdú

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Landscapes with sustainable terracing

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Landscapes with sustainable terracing

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3. Vine vigour control

The terraces built using Mas Martinet techniques are environmentally sustainable, although they may

have two disadvantages from a vine grower’s point of view:

•

They keep the soil more fertile and retain more water than conventional terraces. This does not sit

well with predominant viticulture criteria, according to which excessive fertility and production is

incompatible with grape quality.

•

The construction cost is higher than that of conventional terraces. According to the latest experi-

ments carried out in the Priorat region, the terraces built using Mas Martinet techniques cost bet-

ween 30,000 Euros/ha and 36,000 Euros/ha.

The grape quality and financial feasibility of the vineyard are obtained through vine vigour control, the

second group of techniques presented in this Manual: 

•

Plant architecture (including pinching).

•

Precise irrigation.

•

Plantation framework.

•

Clearing.

In fact, the vigour control techniques described in this chapter overcome the two disadvantages of

building sustainable terraces for the vine grower. The conventional plantation develops between 4,500

and 5,500 linear metres of production branch per hectare, with an ELA close to 7,000 m

2

. As indica-

ted later on in this Manual (Section 4.1), the application of vigour control techniques to sustainable

terraces provides around 12,000 linear metres of production branch and an ELA easily in excess of

20,000 m

2

, maintaining and even increasing the grape quality, preserving the soil and retaining rainwa-

ter. The greater productivity of the vineyard using vigour control techniques provides the same grape

production as with a smaller piece of land. Therefore, as well as the environmental benefits described

in Chapter 2, reforestation is reduced for the vineyard plantation. 

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Two additional techniques are also described that are not strictly necessary for vine control but that

do improve its effectiveness and eco-efficiency:

•

Plant cover.

•

Disease control using a specific model.

3.1. Technique basics

In the Priorat region in the early 90s, old vines produced the base grape for preparing good wines. As

a result of Mas Martinet’s experience in old vineyard operations, it was seen that grapes with small,

loose berries were suitable raw material for top quality wines: 

•

Loose berries have more space to grow, are more aerated and exposed to the sun, making them

less vulnerable to blight and rotting and, above all, ripen much more evenly. 

This basic observation was proven by ripening tests that compared large, compact-berry grapes

with small, loose-berry grapes. The curves indicated in Figure 3.1. show the likely alcohol content

for each grape berry in graph form. In the case of the compact grape, a high percentage of berries

either do not reach or exceed the required alcohol content. This percentage is much lower for loose

grapes. In other words, with regards to the average values required, the compact grape is much

more disperse (standard deviation on the Gauss curve) than the loose grape, thus explaining the

difference in quality. 

Figure 3.1 Comparison of the likely alcohol content of two types of grape berry

Compact grape

Loose grape berry

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likely content

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likely content

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Grape ripening and wine quality

During ripening, the sugar to have accumulated in the plant through photosynthesis passes through the sap to reach the grape. Through

the action of sunlight, the hypodermic cells of the berry (in the skin) perform the enzymatic synthesis of the polyphenols and the aro-

mas using the sugar. The polyphenols form an extremely wide and diverse group of compounds (tannins, flavonoids, etc.) that give the

wine colour, bouquet and flavour. It can be said hat all the characteristics subsequently reflected in the wine are from the sugar of the

reserves that synthesise the polyphenols during ripening.

Ripening forms part of the vine’s reproductive strategy:

•

When the fruit ripens, it gives of smells that attract animals. 

•

Animals eat the ripe fruit.

•

In the ripe fruit, the seeds are already covered with lignin that animals cannot digest. They therefore expel them without spoiling

them and allow the plant to reproduce.

The quality of a wine is determined by three main characteristics: 

•

Balance.

•

Concentration.

•

Character.

- Balance. A wine is balanced when its aromas and flavours are faultless and reduce gradually until they disappear, with no sudden

changes or peaks. 

Balance depends primarily on the ripeness of the grape. If the grape is not sufficiently ripe, green tannins are extracted during mace-

ration that are responsible for different problems in the wine: astringency, dry mouth, acidity, etc. Excess ripeness causes sweet-

ness with excessive tastes of dried fruits or figs. It is therefore extremely important for all grape berries to reach the required level

of ripeness at the same time, i.e. evenly, with no excessively ripe berries next to others that are still green. 

- Concentration: as well as the quality of the polyphenols and aromas, their quantity is also important so that the wine can mature

correctly and produce evolving aromas during ageing. If the grape contains a small quantity of polyphenols, the biological activity

of the wine during ageing will alter all the compounds and the wine will loose its required characteristics. 

- Character: this characteristic enables wines with a good basic quality (balance and concentration) to stand out. The character of a

wine depends on the “terroir”, the climate, the grape variety and the author.  

Whereas the balance and concentration can be assessed quite objectively by an expert, character is much more subjective. As with

any work of art, the character of a wine can adapt to a greater or less extent to the specific tastes of each individual. 

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