ALL NATURAL CONDITIONS that affect the growth of the grapevines and therefore influence the development and storage of constituents in the grapes are summarily known as site factors. Apart from affecting the constituents and aroma of the grapes (primary aromas), these factors also have a major effect on the processes during fermentation (fermentation aromas) and storage (storage aromas) of the wine. The interaction between soil, climatic and topographical factors produce grapes and wines with a defined and unique provenance.
      The soil is an important site factor. The water and nutrient balance has a profound effect on the wine style and the development of aroma. The texture of the soil or the particle size distribution has a direct influence on the water balance and therefore the amount of water available to the vine during the vegetation period. Thus, plants will experience water stress much more often on sandy or stony soils. In contrast, silty soils, e.g. soils on loess, are much better at retaining water. Vines growing on these soils will only very rarely suffer from low water supply. The Riesling style also seems to be greatly affected by soil pH and natural calcium carbonate content. Wines produced on alkaline, calcareous soils have a higher pH-value and tend to be better buffered. These wines taste very different from those produced on acid, carbonate free sites. The soil calcium carbonate content and pH-value as well as the texture are determined by the parent material of the soil.
      The climatic conditions of a site, the macro-, meso- and microclimate, play a central role in determining the ripening conditions. Degree of latitude, aspect and slope influences the growth of the grapes. However, it