Sweet tasting, crystalline food, which is obtained from various plants such as sugar cane or sugar beet. Depending on the number of carbon atoms in a sugar molecule, there are the terms pentoses (5 atoms = chemical formula beginning with C5) and hexoses (6 atoms = C6). In the metabolism of the human body, the sugars are oxidized, which releases energy when heat is released, which in turn causes motor functions. Most plants produce sugar by photosynthesis in the form of sucrose and store it in the cells. Some is converted into starch and stored in the stem and roots.
Other plants, such as the grapevine, break down sucrose into its components glucose (glucose) and fructose (fructose) and store them in the grapes' berries. Both types of sugar are so-called monosaccharides and belong to the group of hexoses. During fermentation, they are directly converted to 90% into ethanol and carbon dioxide, whereby this occurs more quickly with glucose. Fructose sweetens many times more than glucose and also dominates the residual sugar. The arabinose, rhamnose, ribose and xylose belonging to the pentoses are not or hardly fermentable and remain as residual sugar.