Term for the sum of all types of sugars that can be determined by iodometry due to their reducing effect on an alkaline copper solution in the wine. This includes the types of sugar that can be fermented by the yeasts during fermentation, such as glucose (grape sugar) and fructose (fruit sugar), as well as the types of sugar that cannot be fermented or can hardly be fermented (pentoses). The quantity results in the content of residual sugar in the wine in g/l. The value "reducing sugar" is determined analytically in Austria when the state inspection number is assigned. See also under total extract and Maillard reaction.
I have great respect for the scope and quality of the wein.plus encyclopaedia. It is a unique place to go for crisp, sound information on terms from the world of wine.
Dr. Edgar Müller
Dozent, Önologe und Weinbauberater, Bad Kreuznach