Total extract (dry extract) refers to all substances that are dissolved in the wine and remain after distillation (evaporation) of the aqueous-alcoholic portion. The total of all minerals and trace elements is called ash, the amount of all acids is called total acid and the amount of all sugars is called residual sugar. By means of metabolomics (a new method of analysis at the molecular level), around 7,000 different substances have been identified in wine. This not only makes it possible to determine the ingredients present in a wine, but also the quality and origin, as well as any manipulations or wine adulterations that may have taken place. The calculation is made in grams per litre (g/l) to an accuracy of 10-1. By far the largest part is still unknown. The approximately 50 most common ones, together with their interaction, make up the composition or the very special quality of a wine.