The monosaccharide (simple sugar) is better known as grape sugar or dextrose. This type of sugar is formed first in the grapes. During vinification at the beginning of fermentation, it is found with fructose (fruit sugar) in a ratio of one to one in the grape must. Both types of sugar belong to the so-called hexoses and are together called invert sugar. They have very different sweetness levels; fructose is about two and a half times sweeter than glucose. During fermentation, glucose is preferentially converted into alcohol and carbon dioxide. This is why fructose dominates in the residual sugar of the wine. In contrast to fructose, glucose cannot or can only with difficulty be broken down by the human body in diabetes (diabetes).