The Chardonnay wine olfactory concept revisited: A stable core of volatile compounds, and fuzzy boundaries

An earlier study by the same team showed that Chardonnay wines have common olfactory properties by which wine experts can recognize them. The specific Chardonnay olfactory space was also tentatively linked to the relative concentrations of 29 volatile compounds, regarded as possible aroma-impact compounds. The question now is whether or not those initial results hold independently of the sample under consideration, that is, whether these sensory and chemical spaces are vintage-specific. A series of investigations was conducted on a new set of 46 wines (23 Chardonnay wines and 23 non Chardonnay wines) using the same sensory (wine typicality level) and physico-chemical (Gas Chromatography-mass spectrometry-selected ion monitoring: GC-MS-SIM) approaches as in the earlier study. The sensory space of Chardonnay wines has been identified again in this new study. Compared with white wines of other grape varieties, Chardonnay wines do have distinctive and recognizable olfactory characteristics. LSD tests carried out on the chemical data and a PLS analysis predicting wine typicality level from the chemical data showed that the relative concentrations of 35 volatile compounds affected the wines' typicality scores. Of the 35 compounds, 18 were already among the 29 possible aroma-impact compounds identified by the earlier study. These 18 common volatile compounds seem to be vintage-independent and as such might represent the core of the Chardonnay wine olfactory space. The others seem to be specific to the new wines tested and may contribute to the fuzziness of the boundaries of the Chardonnay wine olfactory space. These results emphasize the complexity of the odor quality of Chardonnay wines, with some volatile compounds remaining stable across vintages, while others are specific to enological practices and to vintages.