The climate

The Rioja is defined, from the point of view of climate, as an arrowhead of Mediterranean light within the mists of the Cantabrican sea. It is an area of northern luminosity within our peninsula. It has, in turn, another singular characteristic; The Rioja, through the Basque Country, which is the area of the Cantabrican region which has the lowest mountains, receives winds from the Atlantic ocean with more ease than other inland areas where they are intercepted by the mountains of the "Picos de Europa" and the Pyrenees. The winds which the vineyards receive from the Atlantic bring with them a breath of quality, much in the same way as in Jerez, Oporto, Bordeaux, the Rhine, etc. Thus, the vineyards of the Rioja represent a delightful blend of Atlantic and Mediterranean climates.

Within the Rioja itself, the climates are extremely varied and a simple observation of the crops gives some idea of this. From Haro to Alfaro vines, almonds, olives and peaches are grown in progressive stages. The specific data is shown in the following chart:

Locality	Annual rainfalll	Average temperature	Hours of sunshine
Haro	499 mm.	12,7° C	1.977
Logroño	390 mm.	13,1° C	2.150
Alfaro	284 mm.	14,4° C	2.385

Viticulture combines these pieces of data by means of the "bioclimatic index" which takes active temperatures into consideration, i.e. those of more than 10· C, the days of sunshine and rain; all with reference to the 190 days counted annually from bud break to the grape harvest. In this way, the "bioclimatic scale" gives the Rioja Alta a figure of around five, a little more (not quite six) for the Rioja Alavesa and nine for the Rioja Baja. Figures of between four and seven are to be considered optimum for fine table wines. At lower levels, "chacolis" (a slightly acidic white wine made in the Basque Country) are produced and at higher levels, low quality wines.

The clearest way in which climate influences the quality of wine is in the alcohol content. The higher the temperature and level of luminosity, the more sugar the grape will have; therefore the wine will have a higher alcohol level. In this way, and as can be seen on the map below, wines from "Las Conchas de Haro" to Alfaro vary from ten to fifteen degrees of alcohol, although wine producers try to reduce these extremes by blending selected wines.

But fine wines, such as those produced in the Rioja, cannot be valued according to their alcohol content; but according to the colour, palate and aroma, which in some respects is opposite to their alcohol content. Thus, the fine wines which are bottled in the Rioja usually have between eleven and thirteen degrees of alcohol.

The comments we have made regarding climate refer to the specific habitat of the vineyards. Nevertheless, there are annual climatic variations which make the grape harvest very good in some vineyards and deficient in others. The more important of these variations are due to frost, wind and rain.

When we mention frost, we do not refer to the cold in winter, but temperatures of under four degrees which affect the vines during spring and autumn. These cold spells slow down the vegetation process of the vine and cause harvests of unripened, low-quality grapes. When these cold spells occur regularly in May and June, low-quality vintages can be predicted.

We have detected an interesting piece of data: good, high-quality wine harvests are preceded by prevailing northerly and westerly winds during growth and until September. On the other hand, poor-quality vintages are preceded by prevailing winds from the South-East. The beneficial effect of the Atlantic is clear.

Excess rainfall provokes the risk of infection from dangerous diseases of the vine: mildew, and grey rot. In these cases the wines have poor colour.

It is important to understand that Rioja wine is the product of very specific climatic conditions and therefore, for Rioja wine producers, the risk of a sub-standard harvest is ever present. Although Rioja wine reaches a certain quality level every year, only some years does the climate allow an extraordinary or excellent quality appropriate for constituting "Reservas". In other words, wine of sufficient character and structure to enhance quality after many years of ageing.