Term for the period during the growth cycle in which there is little or no rainfall (Rain) there. For the assessment of the negative impact on viticulture, the complex relationships between soil water supply, air temperature and humidity significant. This also depends on the area and the predominant area climate from. In normally cool and humid wine-growing regions, drought or drought can occur especially when producing red wine can also be an advantage if the resulting lower growth results in a natural, quality-enhancing process yield restriction results.
In extreme cases, this leads to Rebstock to the water stress (Drought stress), which is particularly evident at the time of maturation (Maturity) disadvantageous earnings and the quality of the wine (in Europe this is usually from August to September). In connection with high daily temperatures above 40 ° C, there is also heat stress, In hot and dry regions with too little rainfall, an artificial one is carried out preventively irrigation, This is common in southern countries or overseas, such as Australia or South America. Within the EU, such measures are usually the exception or require approval.
Certain plants have adapted to the environment in the course of their development and have developed various defense mechanisms against drought and drought (see below xerophilous ). Some grape varieties have a pronounced one resistance against dryness and get by with relatively little water. These are, among other things Airén (Spain), Argaman (Israel), Arinto (Portugal), Bobal. Cayetana Blanca (Spain), Garnacha Tinta or Grenache Noir (Spain, southern France), Lairén (Spain), Viura or Macabeo respectively (Spain, France), Savatiano (Greece), Touriga Franca. Touriga Nacional and Trincadeira Preta (Portugal). In the new breed Drought resistance plays an important role in grape varieties, which is also achieved by "hardening". By the climate Change such properties are becoming increasingly important. See also under climate and Weather,