succinic acid, an acid found to a limited extent in both grapes and wine. Present in low concentrations in ripe grapes, it is a contributor to the fresh or tart taste of the fruit, albeit to a much lesser extent than tartaric acid or malic acid. Like these two principal grape acids, pure succinic acid is a white crystalline solid that is very soluble in water and alcoholic water solutions such as wine.
Succinic acid concentrations tend to be higher in wine than in grapes because the acid is a by-product of the complex nitrogen metabolic processes involved in yeast growth during fermentation. Concentrations are generally higher in red wines than in whites. In some wines, a considerable proportion of the succinic acid reacts with one molecule of ethanol to form an ester, mono-ethyl succinate, which has a very mild, fruity aroma.
