The grape variety, the climate, the vintage, the soil, the physiological ripeness of the grapes at harvest and the art of the winemaker, as well as the metabolic processes that take place during the bottle ripening or ageing of the wine all have a decisive influence on the quality of the wine. In the case of high-quality wines, the quantities of the ingredients result in an optimal, balanced ratio, whereby the proportion of acids, sugar, alcohol and aromatic substances plays a particularly important role (see total extract). By means of the new analysis method metabolomics, around 7,000 different substances have been identified in wine. With this method, however, not only the ingredients present in a wine can be determined, but also its quality and origin as well as any manipulation or adulteration of the wine.
The wine quality levels and designations valid within the EU are described under quality system. All aids, work and measures in the vineyard during the vegetation cycle can be found under vineyard care. Complete lists of the numerous cellar techniques, as well as a list of the types of wine, sparkling wine and distillate regulated by wine law can be found under Vinification. Comprehensive wine law information can be found under the keyword wine law.