Suitability of a region for wine-growing which can be measured by objective criteria. Important criteria are climate and weather, which are of eminent importance for the flourishing of the vines during the vegetation cycle. The exposure (direction of sunlight) or orientation of the vine rows plays an extremely important role, whereby a slope with a corresponding inclination further enhances the effect. In dry areas with favourable thermal conditions, south-east to east slopes are ideal, while south-west exposure is optimal in climatic border areas with thermal deficits but sufficient precipitation. According to research in Geisenheim, the optimal temperature for vine growth is between 25 and 28 °C. Towards the end of the ripening period, it should be between 15 and 20 °C in order to achieve optimum physiological ripeness of the grapes. Sunny days alternating with cooler nights are advantageous with regard to the balance of sugar and acidity. Shortly before the grape harvest, heavy rainfall is undesirable due to the risk of dilution.
Vines growing in cool climates generally produce wines with less alcohol content and more acidity than in warm climates. A cold winter is necessary to allow the vine to hibernate during the dormant phase of the vine to renew its vitality and to kill off pathogenic micro-organisms and pests. The amount of precipitation required depends on various conditions such as water storage capacity and water withdrawal. This in turn is related to the soil conditions. Vines are less dependent on fertile soil types than annual crops. It is not unusual to find sites with very poor soils on which high-quality wines grow. Sufficient supply of nutrients is very important, however. High air humidity, especially in combination with high temperatures, can promote fungal diseases. The minimum climatic requirements:
However, these criteria alone are not sufficient to determine the wine-growing potential of a site beyond doubt. There are sites that are unsuitable for viticulture despite fulfilling many conditions. A large part of the most important wine-growing regions are situated at an altitude of between 300 and 600 metres above sea level. However, there are also isolated vineyards at extremely high altitudes; the highest vineyards are even above 3,000 metres. Good to ideal conditions for quality viticulture exist above all in the geographical areas known as the vine belts, from the 40th to 50th degree of the northern hemisphere and from the 30th to 40th degree of the southern hemisphere. More than 95% of the vineyards are located here. The proximity of large bodies of water has a moderating effect, especially when there is a risk of frost. Especially in Europe, many important wine-growing areas are located along rivers, lakes and seas with ideal conditions due to the formation of valley slopes and thus excellent sunshine.
Depending on the climatic conditions, the EU countries are divided into wine-growing zones. The term terroir, coined in France, describes the influence of origin, climate and soil in combination with the cultivated grape varieties and the local winemaking culture, all of which have an effect on the special and unmistakable characteristics of the wine grown there. A table of the approximately 100 wine-growing countries with vineyards and annual quantities is included under Wine Production Quantities. Climate change will bring about significant changes in viticulture in the coming years/decades. As a consolation: not all of them will be disadvantaged - and there are countries that even benefit from it. From the mid-1990s onwards, this fact (also) made the term Cool Climate Winegrowing popular, which refers to the planting of vines in higher areas with continental climatic conditions.
All aids, work and measures in the vineyard during the vegetation cycle can be found under the keyword vineyard care. Complete lists of the numerous vinification measures or cellar techniques, as well as the types of wine, sparkling wine and distillate regulated by wine law are included under the keyword vinification. Comprehensive information on wine law can be found under the keyword wine law.
Source: Minimum requirements: Viticulture of Müller/Kadisch/Schulze/Walg, Ulmer publishing house
Graphics: Der Winzer 1 - viticulture, Ulmer Verlag 2019, 4th edition