100 Years of Rioja Alta

VITICULTURE

THE VEGETATIVE CYCLE OF THE VINE

The productive life of the vine lasts a good number of years, sometimes up to a hundred, but provides grapes for efficient winemaking for about fifty years. There is an annual vegetative cycle which culminates with the grape harvest and restarts the following year. This cycle, unlike many crops, coincides with the calendar year. The inactive period for the vine spans a period, the approximate midpoint of which is the end of one year and the beginning of the next. Accordingly, when we speak of a wine harvest, for example the famous vintage of 1964, we do not only refer to the grape harvest of 1964 but to the whole cycle of the vine which produced grapes in that year.

The annual cycle of the vine consists of different stages which we are going to explain in a simplified way with reference to the calender.

January. The vine rests from November and continues in its latent condition until March when, with the increase in temperature, it initiates its activity. During this period, pruning takes place. This must be done by the vinegrower to remove inefficient shoots from the previous year and give the vine the desired shape and productivity for the new cycle.

March. The "lloro" or bleeding is the first indication of activity in the vine each year. It lasts about three weeks and receives this name from a colourless liquid that flows from the pruning cuts. This liquid changes rarely, but when it does, it takes on a curious red appearance which vinegrowers call "lloro sangrante".

April. When a temperature of ten degrees is reached, bud break occurs; this begins with a thickening of the buds followed by the separation of the scales which have protected them. Some small initial leaves appear or "foliation".

May. At the end of this month, "flowering" takes place. This consists of the opening of the flower with the shedding of the corolla and fertilisation. Sometimes, due to a lack of heat, an excess of humidity or abnormal vigour, the flower does not become totally fertilized, giving bunches with a small number of grapes. It is said then that there has been "corrimiento de la flor", in other words, the flower has not been completely fertilized. Fertilization is popularly called "cuajado" or "setting". The very small initial fruit, which forms the bunch, is very bitter and green. The bunches are called "agraces" or unripe berries and this condition, which lasts until July, is called "agraz".

July. When the month of July arrives, the vine reaches its physiological maturity. It could now reproduce itself, but the fruit is still a long way from being a ripe grape, although the evolution which will end in the grape harvest has already begun. During this month, the stage called "envero" or veraison becomes apparent. The grapes change colour, from green to a yellowish colour in the white varieties and pinkish in the red varieties. Until then it is impossible to distinguish between a bunch of white grapes and a bunch of red grapes. In addition, the grape begins to lose acidity and accumulate sugar.

September. The newly coloured grapes change from being very bitter to very sweet. The skin of the grape softens steadily and the red varieties take on an intense colour. This is the ripening stage, the end of which is difficult to define but concludes with the harvest.

October. Harvesting takes place, and consists of cutting the bunches for wine-making. The enologist will judge when this is advisable, depending on the type of wine which is required. If it is brought forward, the wines are fresh and green; if it is put back, wines of higher alcohol content and more colour are obtained.

November. The vine begins to wither even before the harvest. It is a progression towards the latent winter stage. The vine leaves harden, the sap accumulates in the stem, the leaf changes to a tobacco colour and falls. In March another cycle will initiate with the "lloro" or bleeding.

PLANTING

It is not a simple matter to plant or "place a vine". All the soils of the Rioja are apt for vines, but it is better to discard the very rich "black" soils, very cold soils or those areas prone to frost damage. The first of these would yield a large quantity of grapes but with a low alcohol content, and the last would give very green grapes.

Having chosen the land, it is necessary to remember that vines send their roots very deep and it is necessary to plant them in deep soil. This is done with subsoilers or ploughs to a depth of one metre. It is easy to understand how the use of tractors has extended the land available for planting vines. There is a lot of land in the Rioja with alluvial soil which rests on a limestone crust at a depth of less than metre. This, formerly, was impossible to work with only mules and donkeys. Today, however, this crust can be broken to extend the nutritional area for the roots of the vine.

It should also be borne in mind that after a vine has been uprooted, the land should be cultivated with cereals or leguminous plants for five or six seasons before replacing the vines; although today there are special fertilizers which can accelerate this process.

What vine should I plant? This is the first question which the vinegrower asks himself. This has two aspects as each vine also has two parts. Its roots come from one type of vine called the "foot" and the part above ground is of another type called the "wine-producing" part. The reason for this double origin of every vine is due to the need for strong roots and good grapes. The "foot" is chosen in accordance with the type of soil and the "wine-producing" part according to the type of wine one wishes to obtain within the six basic types of the Rioja.

How many vines per hectare? Traditionally in the Rioja from 2,500 to 3,500 vines are planted per hectare, the maximum density being attained in some parts of the Rioja Alavesa. None of the new technologies advise that this plant density should be increased or decreased.

Once sufficient depth has been given to the vine, lumps of soil are broken up to allow the plant to settle firmly in compacted soil without gaps, avoiding frost and the consequences of drought. Subsequently the land is marked out with string and stakes to determine the rows and lanes.

There are still numerous plantations which use the old planting frame or square. Recently, with the advent of machinery for working with tractors, it has become necessary to give the lanes greater width and a specific orientation in order to receive sunlight; also to protect the vines from the wind, prevent erosion from rain and improve working conditions for tractors.

The classical frames are of 1.8 m x 1.8 m in the Rioja Alavesa and Rioja Baja, which means a density of 3,086 vines per hectare and 1.9 m x 1.9 m in the Rioja Alta which, in turn, represents a density of 2,770 vines per hectare.

The introduction of new frames allowing for tractors, has not altered the density of vines per hectare, although it has modified the surface area dedicated to each vine. Thus, a frequently-used modern frame measures 2.6 m x 1.3 m, and means 2,958 vines per hectare.

During more remote times it seems that the "royal frame" used measured two "varas", i.e., 1.67 x 1.67 m.

It is customary in the Rioja to carry out planting from February 15th and before 20th April. Taking advantage of the Spring rains and humidity, avoiding the droughts and frosts of other seasons.

STOCK AND GRAFT

After the phylloxera invasion, the roots of local vineyards were seriously damaged and it was necessary to consider reconstruction. Use was made of vines typical in phylloxera prone areas. If this pest came from North America, the solution also came from that country, where vines and disease live together in harmony. The European vines were reconstructed on an American root which was resistant to phylloxera; the upper part being capable of producing European grapes, the grape of the American vine is inappropiate. In this way, almost all existing vineyards have a "foot" or stock of the American vine with a graft of traditional vines from the Rioja.

Another circumstance influences the grafting operation. This involves a chemical reaction of the American vine root. This vine does not stand up as well as the European vine to the so-called active limestone in the soil, which in the Rioja can be plentiful.

Therefore, faced with the phylloxera attack, vinegrowers sought American vine roots resistant to the limestone present in their vineyards. But other factors, in addition to limestone, are taken into consideration when choosing a stock, such as: Depth of the arable soil, the variety of European vine which is to be grafted, dryness of the area, the desired production, the salinity of the soil.

What happens if the vinegrower does not graft? If the vinegrower plants a vine without grafting, he might do this with European vines which are susceptible to attack by phylloxera; their roots would not resist the attacks of this insect. Its productive life would only reach twenty years. But if he does not graft, we can also suppose he will plant American vines, in which case the vine lives a long time but produces inadequate grapes for wine-making. They will be rejected by the market due to a colour component called "malvina".

The European variety of vine, from which we obtain our wines has the scientific name of Vitis vinífera, while the American vines, from which come the phylloxera-resistant stocks, are of the following species:

Vitis rupestris, Vitis riparia, Vitis labrusca, Vitis berlandieri.

From experimental crosses of these American species, numerous stocks have developed. The most common of these, as used in the Rioja, are as follows:

Popular name Origin of cross Resistance to active limestone up to
3.309 Riparia x Rupestris 0-11%
Rupestri de Lot Rupestris variety of Lot 0-14%
99 R (Richter) Berlandieri x Rupestris de Lot 0-17%
110 R (Richter) Berlandieri x Rupestris 0-17%
161-49 Ripari x Berlandieri 0-25%
41-B Chasselas (V. vinifera) x Berlandieri 0-50%

The grafting operation consists of joining recent cuts of the stock and graft. The cut is usually clean and oblique although it can be made with split mesh or with a scion. After a year in the soil, this grafting operation can be carried out where the stock is planted. This is the traditional system in La Rioja. In addition, it is possible to operate with the "taller" or "workshop" graft, this is the joining of the stock and graft in the nursery before planting in the vineyard. In this way a year is gained in the process of preparing the vineyard. Recently, the "pote" or "pot" system has been used, whereby grafts made in nurseries and rooted there are later transplanted to the vineyard with some earth which envelops the roots in a small perforated tub which afterwards decomposes in the soil.

ROOTS

The vine gives out a tap-root from seeds, i.e., a main root which descends deeply into the ground and sends out branches at different heights. Nevertheless, according to vine-growing practices, use is not made of the germination of seeds, as the vine reproduces by means of "estacas" or cuttings which are rooted in nurseries and transplanted to the vineyard. In this case, the root develops in stages from the bottom end of the cutting, although, after some years roots also come out of higher parts of the cutting.

The dimensions of the root system of vines, as in the case of other arborescent or shrub-like plants, depend on the characteristics of the soil in which they are planted, on the planting density, on the type of stock, on the characteristics of the variety and the cultivation method (ploughing, working, fertilization, etc.).

The type of soil is highly important for the shape and dimension of the root system of the vine. For a "royal frame" of 2 x 2 metres and a 20-year-old vine, we have found the following dimensions:

Soil type Max. depth (metre) Max.extension
(radius in metres)
Max absorption
(at depth)
Marl 1.15 1.90 0.50
Ferrous clay 1.30 1.40 0.70
Alluvial soils 2.00 1.90 0.90

The dimensions in alluvial soil refer to soils where the limestone crust has been broken, as is the case with present planting techniques. Formerly, the maximum depth of this soil would only be about 60 centimetres.

The planting density and frame have influence on the development of the root system. When the density is high, i.e., when there are other vines very near, the vine tends to send its roots very deep. On the other hand, when they are widely separated, after some years the roots spread and do not go very deep.

In marl soils, the roots can easily penetrate the cracks in sandstone-limestone and develop in a very irregular way, both in shape and depth. It is interesting to note that there are vines planted in rocks by means of a drill which perforates the soft rock as far as the stratum of loose soil. In this way, the vine seems to grow on the rock, but this only covers the non-absorbent part of the root. Underneath, the roots extend easily.

TRUNK AND MAIN STEMS OR "ARMS"

In the Rioja, vines have a shape similar to a "candelabra". This does not occur naturally but is the consequence of pruning. The vinegrower obtains this shape intentionally during the pruning operation each year. This shape is also known as "goblet" pruning.

Two or three years after grafting and at about 10 cm from the soil, the trunk of the vine divides into three branches. On each branch, two canes are cut back at the base, leaving two buds on each, but year after year and once the three branches have formed, these do not continue to fork. Although two buds are left on each spur, and from these canes shoot each year, the upper one is eliminated and the lowest, two buds away, is pruned in turn. In this way, every year, the trunk which supports three branches, each with two spurs, is left with twelve buds, two on each cane.

Step by step, year after year, the trunk and branches become coriaceous with black, exfoliable bark. The canes which become renewal spurs and afterwards form part of the "arms", change from green to a reddish colour, then ochre, which pales and after two years, becoming greyish and then black or very dark brown.

Up to an age of twenty-five years, the branches grow in the harmonious form of a goblet or cup. Afterwards, and to avoid excessive height, the vinegrower tends to cut back further growth producing, during the course of the next twenty years, spiral or zig-zag shapes, sometimes with a downward tendency. After more than sixty years, the shapes can become picturesque.

In the Rioja Baja there are pruned vines with shorter branches but with a higher common trunk. In the Rioja Alta the branches start at 20-30 cm and the cup shape reaches 50 cm after twenty years. On the other hand, in the Rioja Baja the trunk reaches 40 cm and the branches an extra 10 cm.

Several vegetative forms arise each year in the vine as a whole.

At intervals of 15-25 cm along the canes there are thicker sections which indicate knots. These bring together buds, leaves, tendrils, bunches and internal diaphragm.The arrangement of the trunk and branches according to the wishes of the vinegrower, does not have any definite effect on the quality or quantity of grapes. In the Rioja it has the shape of a goblet as this is the simplest shape to occupy the space available in the vineyard.

As a consequence of modern cultivating methods, without horses, the arrangement of the vines and their shape can be varied to simplify work. This, does not influence the quality of the wine as long as no attempt is made to obtain a higher yield than that permitted by regulations.

THE PRODUCTIVE PERIOD

Vines can live up to one hundred years. Nevertheless, from the point of view of producing grapes for wine-making, the life of the vine is considered as being shorter. The maximum life for a vine in the Rioja, although defined by age, is the accumulation of factors which exhaust the vine, such as:

a) Repeated diseases.
b) Pruning done in such a way as to increase production.
c) Droughts.
d) Damage caused by machinery.

Lately, in isolated instances, we have found cases of sudden withering of Rioja vines. This occurs in vines during the ripening stage, which, apparently, have healthy roots, trunk and produce a large number of grapes. Suddenly, the green parts of the vine begin to dry up, the leaves fall and the bunches cease to ripen. The following year the vine shows no sign of life.

The productivity of the vine in the Rioja is of great interest to the enologist due, not only to the amount it produces, but to the quality of its grapes.

The enclosed chart has been prepared to show the variations in production of a vine throughout a period of one hundred years. Also for production which ranges from zero to three kilogrammes per vine. The thick broken line represents the strict production for each year and the fine dotted line expresses the tendency of each stage in the life of the vine. These tendencies are as follows:

· Vine-formation stage. It spans the period from zero to four years. Productivity is negligible.
· Stage of increasing productivity. It spans the period from five to thirty-five years, with an increasing production per vine from 0.2 Kg to 2.7 Kg.
· Stage of declining productivity from thirty-five to fifty-four years. During this stage, productivity descends from 2.7 Kg to 0.75 Kg.
· Final stage. From fifty-four years onwards vines produce a steadily decreasing number of grapes, with levels of under 1 Kg per vine.

Therefore, at its most profitable with regard to quantity, the vine is estimated to be about forty years old. In order to pay off the high costs of planting, attempts are made to shorten the "formation" period of the vine. But if we try to force production (as is shown by the yellow line) we also bring forward the stage of declining production; the period of productivity would only reach thirty years. However, as in so many cases, the conflict is essentially one of quality and quantity. Profitability in terms of quantity occurs during a maximum period of forty years, but better quality is attained after the twentieth year.

Another interesting piece of information is that the Control of Origin of the Rioja admits a maximum production per hectare of 6,500 Kg of grapes for red wines (48 Hl/ha). This means that any vine pruned strictly according to local practices between years 25 and 37 of its productive life, exceeds the official rate set by the Control of Origin.

Above the brown line denoting productivity stages, the climatic circumstances of each year allow fluctuations in the quantity of grapes produced by about 40%, both above and below the normal figure.

Sometimes, in order to revitalise vines of more than sixty years old the trunk is cut a short distance above the ground so that the latent buds of the old wood can give rise to a new productive structure. Thus the distance over which the sap has to flow is reduced. One of the causes for exhaustion is the progressive height of the vine trunk with the consequent difficulty for the movement of nutritive liquids.

Soils have a negligible influence on the life of a vine, although it seems that dry soils, marls, far from underground streams can, as a result of droughts, limit the life of a vine.

ANNUAL CULTIVATION

Vines are domesticated plants which would have great difficulty in adapting to the wild. Frequently, vines which are not looked after become diseased, wither and die, even though it would appear natural that, without pruning and cultivation, they would develop into a thick tangle of leaves and canes. An abandoned vine dies despite having soil and sun.

The attentions which vines must receive annually in the Rioja in order to maintain their level of quality production are several and can be grouped into:

· Care of the soil.
· Care of the plant.
· Treatment of possible diseases.

We have already seen that the vegetative cycle of the vine spans the period from April to October. During this time care is necessary, especially during the initial stage from budding to flowering. This period lasts about sixty days (April and May), the vines go through two complex, delicate and energy-absorbing stages: Budding and flowering/fertilisation, both coinciding with the wet period of spring in the Rioja.

For all these reasons, from April 1st until the end of May, greater care must be given than at other times.

The attention given to the soil has the basic aim of maintaining the humidity received by the soil and to prevent rain water from running away. The attention given vines during this period tends to simplify the growth required to produce the canes. In turn, favouring in the development of bunches or the fertilization of flowers and to give the green mass of vines a pleasant appearance.

At the beginning of April it is usual practice to separate the earth that some months before had surrounded the trunk to defend it against winter frosts. This separation of earth creates a space around the trunk which enables rain water to penetrate the area next to it.

About two weeks later, the vine having already sprouted, buds appear on the old wood of the trunk, spoiling the appearance of the vine and consuming energy and water. For this reason, "espergura" or trimming takes place, which many Rioja vinegrowers also call "espervura". In short, it is a "purging" or cleaning of the trunks. Shoots sprouting from the trunk are removed by hand. In addition, other plants will have grown spontaneously among the vines, these are also removed. They disfigure the vineyard and consume the scarce amounts of water. The soil is broken up at the same time to allow for the absorption of the rain. If the soil were not loose and broken up, rain would run off without penetrating into the soil, especially in the case of vineyards planted on hillsides.

At the end of April, canes tend to develop smaller leaves among the main ones, fruit of the secondary buds on these canes. This would lead to an excessive ramification of the vine. Therefore these shoots are removed by hand in an operation which is called "desniete" or the removal of lateral shoots. Due to this operation, the development of excessive foliation is avoided and energy is retained in the lower part of the canes where the clusters of grapes are formed. At the same time the weeds are again removed so that the soil, the upper layers of which are loose, can withstand the loss of moisture due to evaporation in the summer heat. As of that moment the development of the canes does not allow working between the vines, although this is facilitated by the rows and lanes of modern vineyards.

At the end of May "despunte" or "tipping" is carried out consisting of cutting back the lengthwise growth of the canes and retaining the energy involved to favour flowering. Tipping may be repeated after flowering for the benefit of the clusters of grapes: cutting back leaves at the same time so that the grapes can swell. Nevertheless, in vineyards which are unprotected from the wind, tipping, or the cutting back of about 40 cm from the end of the cane, is also necessary in order to remove a surface on which the wind can exert a considerable force, breaking them off at the base. This part is still tender and weak but in June hardens and changes into wood.

Treatment to prevent the possibility of disease can be made at the same time as this work is carried out.

RIPENING

Ripening is the culmination of the fruit on the vine. It begins in August, after the "envero" or "veraison" and involves a series of gradual processes which start with the green grape and finish with the ripe grape; which is picked and goes on to thefermentation process.

It is an over simplification to say that when the grape ripens its sugar content increases. This is clear, but is only one aspect of the many which can be observed.

We must distinguish between physical aspects such as the variation in the size of the grape, variation in its hardness and weight, and chemical aspects such as the increase in sugar, the loss of acidity and oxidability.

For Rioja wine, the ripening of the grapes involves a series of complex changes in the grape from August to September.

Increases: The sugar content increases in the grape, which afterwards will produce the alcohol. The weight and size of the grape increases as well as the oxidability of the must, not forgetting the colour of the grape skin in the case of red varieties.

Decreases: The acid content goes down, and with it the acid taste as well as the hardness of the skin.

We can understand that if we bring the grape harvest forward two weeks, we will obtain a wine with a lower alcohol content, less colour and more acidity than in the case of a late harvest.

The data on these charts has been taken from the Rioja Alta (Cenicero, Briones, Haro and Villalba). The typical date of the grape-harvest of this area is the festival of Santa Teresa. A date which indicates, year after year, an acceptable level of ripeness for the great wines of the Rioja.

THE HARVEST - QUALITY AND QUANTITY

The harvest is the traditional operation of collecting grapes and is, partly representative in itself of a season of the year: the Autumn.

Rioja wineproducers usually collect their grapes during the first fortnight of October. However, year in, year out, the question arises-when to harvest? The weather during the year may have been favourable and the harvest can be brought forward, or unfavourable and make a late harvest advisable. During that fortnight, any delay means collecting the grapes at a more ripened stage than harvesting at the beginning of October.

The bodegas decide when to harvest their vineyards after analysing their grapes by means of a density meter reading of the must or by means of a refractometer. This indicates that they will produce a wine with a certain degree of alcohol.

Modest wineproducers depend on old fashioned methods. They know that when they squeeze the grape between their fingers and it produces a sticky sensation, the wine might reach twelve degrees. They also know that when the stem begins to turn brown there is no beneficial circulation between root and leaf. On the other hand, some years, the leaves wither early and fall, or turn yellow or brown. The vine grower knows in this case that further ripening is not desirable and it is advisable to harvest.

In general terms, the harvest depends on weather conditions in Autumn. In the Rioja, as in many inland areas, it rains during two periods of the year, in Spring and in Autumn. The rains of Autumn do not benefit the grapes if they occur after the beginning of the month of October. They can even prove to be prejudicial, softening the skin of the grape and favouring the growth of moulds, called Botrytis. This deteriorates the film to the extent that red musts become brown and whites musts excessively golden or brown, too. In these cases, after the rainy season has commenced, it is advisable to start harvesting immediately.

Typically, small wineproducers take advantage of weekend visits from their relatives for this purpose.

Although there is talk of mechanical harvesting in the Rioja, the grape picking is still done by hand and labour costs are fixed at a tenth of the selling price of the grapes.

The harvesting operation is carried out by manual cutting with a curved knife called "corquete". The wineproducer places his left hand under the bunch and with the other moves the "corquete" upwards against the base of the stem. The bunch falls gently into his hand and he transfers it to the collection basket, which are shaped like a truncated cone and have an approximate capacity of 20 Kg. They are open-weave, made from intertwined chestnut fibres or, in some cases, from wicker. However, in the Rioja, chestnut fibres are more typical. Recently, rubber baskets have appeared of the same shape and capacity. Their maximum diameter is usually 55 cm with a width of 45 cm and a depth of 40 cm. They have two handles.

Once full of grapes, the baskets are carried to the place where the "comportas" or tubs (wooden containers with a 100-Kg capacity) are located. These tubs are in turn loaded onto mules or donkeys, carts or trailers. Today, loading and transport is done by trailers which can hold up to twenty tubs. Horses can carry two, one on each side, like saddlebags, and carts can carry four or six.

"Comportas", or tubs, are shaped like truncated cones, open at the top with a diameter of 60 cm, 1.2 m in height and a base of 40 cm. in diameter. They are made from poplar or chestnut wood with 24 side pieces or "staves". The top has a thickness of 2 cm and the bottom, 4 cm, to withstand the friction of movement on the ground, due to turning and being supported on a single point when tilted by workers. The staves are fastened by four to six lateral metal hoops. They are of a truncated cone shape so that, when empty, they can be piled one inside the other. When full, due to the inclined angle of the side wall, the lower bunches are prevented from being crushed by those on top.

The first harvesting operation, one week before the grape picking, is to soak the tubs in water.

During the harvest these tubs, when they arrive at the bodega, are emptied into the tank or grape mill by being tilted on the edge of the tank, which, many years ago, was a window at the top of the bodega of the wineproducer.

Today, grapes are also carried in tractor-driven trailers, lined with a watertight canvas cover.

The time which elapses from the moment the bunch is cut to their arrival at the bodega has a very important effect on the quality of the wine. The shorter the time, the more probable it is that the wine will be of high quality. Harvested grapes which are kept in baskets for one day cause mould which can be tasted in the finished wine.

If the grapes are kept for one day in the tubs or canvases, the must and resulting wine develops a vinegary taste. The wineproducer realises a need for rapid transport, just as the traditional practice of preventing the grapes from being crushed in the tubs limited the to load to 100 Kg.

Today, there are harvesting machines, which collect the grapes by shaking vines pruned by the espalier method (wires placed in a single line with guided canes). This system is not used in the Rioja.

PRUNING

In previous chapters we said that vines are delicate plants. Without attention, they degenerate, taking on a wild look and their production declines.

Pruning is an annual cutting operation; the wood is cut back to avoid the formation of dense foliage, to regulate production, to give consistency to the vine and to facilitate work on the soil.

Distinction can be made between "green" and "dry" pruning. The former is carried out in November or December, also in March, and the latter is done in January or February.

Generally, pruning time in the Rioja is in the middle of the winter, i.e., this involves "dry" or winter pruning. In the higher part of the Rioja Alavesa and Rioja Alta, which are prone to spring frosts, causing a disastrous effect on the quality of the wine, "green" pruning is carried out. After the grape harvest, the leaves wither and fall. The sap of the leaves and canes descends slowly towards the trunk to accumulate and form the winter reserves which will give strength to the new shoots. If we prune when the sap is descending, when the cane is still a little green, part of the sap is removed, i.e., the reserves which would accumulate in winter in the trunk are diminished and the spring shoots would have little strength. However the frosts might cause less damage as the sprouting of buds and leaves would be delayed. If we prune in the middle of the winter, when the sap reserves have already descended to the trunk, it will bring about strong budding; the possible late frosts may damage tender parts of the vine. Therefore, "green" pruning, i.e., with sap in movement, delays budding and protects the vine against Spring or late Winter frosts, but "dry" pruning, in mid-winter does not defend the plant against this risk.

But if pruning is left until late in March, when the vine has bled, generally the vineyard appears overgrown and makes this job difficult. In these cases "pre-pruning", or limited pruning is done, consisting of trimming the canes in December, and carrying out full pruning in March.

Rioja vines have a "goblet" shape, i.e., three ascending stems or "arms". Two "spurs" are left on each branch and two buds on each spur. In this way, the total number of buds per vine is twelve. If we consider that afterwards one cane sprouts from each bud and that each cane bears two clusters of grapes, we can deduce that each vine produces twenty-four bunches. But these theoretical equations are optimistic as there are numerous factors which reduce this amount, such as:

a) Sometimes deficiencies prevent the formation of three branches per vine.
b) Spring frosts sometimes damage the buds.
c) Flowering and fertilisation are not always the same, therefore the "cuajado", or "setting" of the cluster, is different each year, with more or less grapes.
d) Blights and diseases can reduce or obliterate the growth of the clusters.
e) The ripening conditions can increase or decrease the sugar inside the grape, producing clusters with different densities, therefore varying the weight attained the grape-harvest.

In this way we can understand that from twenty-four theoretical bunches, a much lower average, of variable weight, can be gathered per vine.

This type of pruning of twelve buds is typical in the Rioja but in some cases we can observe unorthodox methods which try to leave more than twelve buds to produce more bunches. This is what is called "long pruning". It is somewhat fraudulent and is forbidden by the Control of Origin Regulating Council of the Rioja. In the regulations they specify the pruning of twelve buds, and limit the final weight of grapes produced per hectare to 6,500 Kg of red grapes and 9,000 Kg of white grapes.

Is quantity the opposite of quality? Yes. When the vinegrower decides to obtain more grapes with "long pruning", the wine made is of inferior quality to that attained with authorised pruning methods.

Nevertheless, nature may replace these unauthorised methods; some years the weather conditions are so favourable that the amount of grapes obtained per hectare are extremely high and the quality of the wine is excellent. This was the case in 1964, 1970, 1981, 1985 and 1989.

"Two-bud" pruning on goblet-shaped vines is carried out by cutting the previous cane slightly above the two lower buds. Each year these buds are usually left on the lower cane. In this way the vine ascends in a gentle "V-shaped" zig-zag, but in the case of young vines the tendency is to leave the buds on the higher cane. In the case of very old vines, on the lowest canes, which are usually canes from the previous lower bud.

It has been seen that in western areas of the Rioja, grapes receive sufficient nutrients from the soil and products made in the leaves during vegetation; but bunches do not always receive optimum levels of illumination, being in the shade of twigs and leaves. Such lack of light might bring about low colour levels in cold years. To permit bunches to receive more light, pruning is sometimes made along wires, whereby twigs change from a vertical to a horizontal position. They are fastened in this position and exposed to light from the sides and above. In this case plantations are also made taking into consideration the width and orientation of the passageways, to gain maximum benefit from sunlight. On flat land, the advisable orientation for rows of vines is North-Northwest to South-Southeast.

Within prescribed production limits, this system of training vines can improve the quality of the grapes.

This system is also called "Quarante" pruning.

PESTS AND DISEASES

The vine is a plant which is sensitive to several pathogenic diseases. We could say that the finer the variety of grape, the bigger the risk to the vine and clusters of grapes.To a certain extent, this is easy to understand as fine wines come from grapes with very subtle and delicate skins and are, therefore, soft and fragile. In varieties of grapes with hard, herbaceous skins, maceration produces wines which are not very fine but the hardness of the skin protects the grape from external attacks.

In addition to being susceptible to attack by different bacteria, fungi and insects, different eras have had an important influence. The second half of the last century was noteworthy for two new diseases which settled in European vineyards: Oidium and Phylloxera.

Recently (during the last decade) diseases have appeared in the vineyards of the Rioja which, although not devastating, are new in the sense that they are of recent appearance and their incidence is important; namely, Virosis and the Acari.

From viruses to butterflies of the vine (from the pyralid caterpillar) there is an enormous variation in size. The butterfly of the pyralid caterpillar is, at least, a million times bigger than the viruses which exist in some vineyards. This is general in all vinegrowing areas and the situation in the Rioja shows variations in accordance with its microclimates and varieties.

To describe the most typical diseases which affect the vineyards of the Rioja, we shall start with the smallest, the viruses, which have little importance but are of scientific interest. It is believed that they do not only affect the quality of the wine but also the productivity of the vine.

Their size is several thousandths of a millimetre and their presence can be diagnosed by low grape yields, changes (in some cases) in the colour of the leaves and by the length of the canes or production of double canes. The Rioja vinegrower is not disturbed by the presence of these viruses with respect to the quality of his grapes, but the effects they have on yield are indeed important. We do not know how long these viruses have existed in the vineyards of the Rioja. We only know that their presence has just been noticed. New plantations of vines tend to be made with guarantees of absence of these viruses.

The next largest pest is a bacteria, one thousandth of a millimetre in size, which produces necrosis or the death of some tissues of the vine, delaying budding, producing black spots in the wood or in the medulla of the cane, even on its outer part, and by giving very small clusters of grapes. This is not an old disease. Its occurrence is not important but we have mentioned it as a rare and interesting case; there are very few bacteria which attack vines. This disease is easily overcome and eradicated by disinfecting the shears and cuts when pruning the vine. It is a disease which attacks the red Garnacha of the Rioja which, in general terms, is a very resistant variety to other diseases.

Larger in size than bacteria, there are moulds and fungi which attack the vine and are known in the vinegrowing world as "Cryptogams". We name the most important diseases: Oidium and Mildew. The size of these fungi is variable and difficult to describe with precision. They range from a few thousanths of a millimetre in spores to a tenth of a millimetre in filaments.

Oidium is a new disease in Europe and has existed here only since the middle of the last Century. It comes from North America and its effect was felt intensely in the Rioja at the end of the 19th Century. The risk of infection has been constant since then but the disease is easily contained by spraying sulphur powder on the leaves and clusters. The powder reacts with the sun'heat producing sulphurous vapors which kill the fungi growing on the outer surface of the leaves and clusters. Should the fungi not be destroyed, the effects would be disastrous. It attacks the leaves producing granulation and greyish pilosity on the bunches. Vinegrowers call this "cenicilla" or "powdery mildew"; it cracks the skin of the grape, preventing ripening.

Another very important cryptogamous disease is Mildew. Its importance derives from the penetration of the delicate interior of the vine, growing inside, and thus remaining highly resistant to treatment.

Vinegrowers combat this disease with care by using copper sulphate compounds. The important question is when to treat. This disease is a constant risk and occurs when there is a high level of humidity and heat. Sometimes, sporadically, as in 1972, it causes extreme damage and can destroy entire areas of vineyards. Not only do the green parts in the vine die but the trunk also becomes contaminated. Thus, in 1972, due to the rapid invasion of mildew during the month of June, thousands of hectares of vines were destroyed in Spain.

The vineyards of the Rioja, due to their semi-humid nature, are prone to mildew, but the vinegrower has sufficient knowledge and means to deal with it. Mildew attacks the leaves, first producing an oily patch and later destroying it completely. The same thing happens to the bunch of grapes.

Moulds can also attack bunches during the ripening period and during the harvest. This occurs with the Botrytis mould, which grows on soft grapes destroying the bunch and producing musts with deficient colouring and which are highly oxidable. The resulting wines have un unstable colour.

Acari are enemies of the vine and have appeared in the Rioja within the last ten years. The climatic irregularities of this period have produced cold Springs with hesitant budding allowing these acari, red spider, yellow spider and acariosis, to proliferate easily, devouring tender buds and incipient leaves during May. At first, at the beginning of the seventies, their impact was considerable. In the Rioja we were afraid of an escalation of damage due to acari. Despite everything, little by little the Rioja vinegrower, by means of treatment of pruned wood during the winter, has been able to control this pest. Today, it does not represent a danger, although the risk still exists.

The largest of the pests which attack vines are insects.

Several types of insect attack the vineyards and there are few variations between the different vine-growing areas with respect to the importance of these aggressors.

Phylloxera is extremely important. This has affected, devastated and left its mark on all the vineyards of Europe.

As in the case of Oidium, it came from North America. Both invasions first affected Britain and then crossed the Channel to the Continent. Phylloxera reached Spanish vineyards by sea. Through Oporto and Málaga in 1880 it began to penetrate the peninsula. However it had already arrived by sea in Bordeaux and the South of France: from there it also extended to the Rioja and Cataluña. The first outbreak in the Rioja was in 1899 in the vineyards of Sajazarra, in the Rioja Alta. It was detected by technicians of the Enological Laboratory of Haro.

Vinegrowers took rapid corrective action by means of American vine stocks which are resistant to phylloxera. Rioja varieties of European vines were grafted on these rootstocks.

Phylloxera has two living forms: one which attacks the roots, piercing them, creating knots causing them to lose vitality; the other, an aerial form, with wings, which pierces the leaves, producing galls or bumps, causing the green parts to disappear if the attack is intense. This plant louse represented the most disastrous invasion of vineyards and is latent in all existing vineyards in the world. The only means of combating it is the creation of plants with American vine roots which withstand the root-attacking type and an upper European part of the vine which provides quality grapes and resists the winged version of phylloxera more than American vines.

Another important insect which offers a possible threat to Rioja vines is the vine pyralid caterpillar. In Spring their larvae appear among the roughness in the bark of the trunk and devour tender shoots, even incipient clusters of grapes, and then change into chrysalises, from which butterflies emerge. This insect is easy to control.

Pests and diseases affect Rioja wine both in quality and quantity. The first effect of a disease in the Rioja is to reduce production. A more intense attack can also delay ripening, producing wines with a "green" taste, little colour and a low alcohol level, therefore not appropriate for long ageing, always desirable in Rioja wines.

These are the general effects, but the attacks to which vines are submitted to during the ripening period, such as Botrytis moulds, can reduce the yield, concentrate the sugar, produce less wine but with a higher alcohol content. There is, however, the inconvenience of colour alteration. Every year, technicians have to face the dilemma of the harvest, namely, to pick early without Botrytis and with little sugar, or later, when the grapes have more sugar but Some Botrytis mould. The choice is simple, harvest late and try to treat Botrytis in the bodega.

 


Text and technical data by Manuel Ruiz Hernández,
HTML and presentation by Jens Riis.
All Rights Reserved - 1995, 1996, 1997.