Designation (also air humidity) for the proportion of water vapor in the gas mixture of the earth's atmosphere or in rooms. Liquid water such as raindrops, mist droplets, ice or snow crystals, however, are not included. Humidity is one of the many factors of weather or in the long-term weather conditions of the climate, Of the free ones water surfaces (Rivers, lakes, oceans), individual water molecules always pass from the water volume into the air volume. Absolute air humidity is the amount of gaseous water vapor contained in one cubic meter of air, usually expressed in g / m3.
The most commonly used measure, however, is the relative humidity (RH), which is the ratio of the actual amount contained to the maximum possible amount of water vapor in the air, measured in%. The air can absorb only a limited amount of water vapor. The warmer the air, the higher this saturation amount: at 40 ° Celsius 50 g, at 65 ° Celsius 200 g and at 100 ° Celsius 600 g. When the saturation quantity is exceeded, tiny droplets of water form in the form of fog as well as on surfaces near the ground of dew due to condensation. Humidity is an important parameter for meteorological processes. A relative humidity between 55 to 65% is optimal for humans, animals and most plants.
In viticulture, the humidity has great importance for the growth of the vine. Due to sufficient relative humidity, the intake of nutrients and increase growth, as well as reduce the release of water. In fact, plants give in dry air or too low relative humidity over the leaves very much water to cool the air. By this as evaporation It may be too water stress come. Usually affects during the fruit set (Phase of development of the flowers to berries) high humidity in sufficient sunlight especially in the afternoon by a continuous photosynthesis with optimal formation of sugar and flavorings on the wine quality positive.
Such conditions exist for example in Germany, Austria and Switzerland. Low humidity regions usually have a hot climate. However, increased dew formation as well as high humidity especially in connection with high temperatures can be a number of fungal diseases favor. The critical value for the formation of different molds is about 70% rLF. Also for storage and maturation of the wine in barrel or bottle, the humidity is of great importance. in the wine cellar the ideal value is 70 to 80%. See also under aging. basement mold. bottle aging. Wine Cabinet and wine temperature,