One of the acids contained in wine and also honey in small quantities (also dextronic acid), which belongs to the non-volatile acids. The complete name is D-gluconic acid, the chemical name is pentahydroxyhexanoic acid. It is an oxidation product of glucose (grape sugar). In grapes affected by botrytis (noble rot), the proportion of gluconic acid is greater. At the Geisenheim Research Institute, attempts are being made to convert the glucose in the grape must into gluconic acid by means of the enzyme glucose oxidase, thus reducing the sugar. This is because the gluconic acid cannot be converted into alcohol by the yeasts. This makes it possible to specifically produce wines with a balanced alcohol content (see under alcohol reduction). Lists of all wine ingredients are included under aroma substances and total extract.
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Egon Mark
Diplom-Sommelier, Weinakademiker und Weinberater, Volders (Österreich)