Background of the study
Sparkling wines are produced in different regions worldwide. Their production involves different grape varieties associated with edaphoclimatic characteristics and different winemaking methods, which determine their specificities and, eventually, geographic names (appellation of origin). Sparkling wines can have different concentrations of residual sugar, acidity, ethanol, and diluted carbon dioxide. Sparkling wine with two fermentations is the result of the refermentation of the base wine, and there are two main methods to conduct it: the Champenoise, Traditional, or Classic method, or the Granvas, Bulk, or Charmat–Martinotti method (commonly called only Charmat). In the Traditional method, the second fermentation of the base wine takes place in sealed bottles, while in the Charmat method, the second refermentation takes place in an isobaric tank. The term Champenoise should only be used officially for sparkling wines produced within the Champagne denomination of origin in France (Council regulation (EEC) N° 3309/85 of 18 November 1985 and EEC N° 2333/92 of 13 July 1992).
Each method has its technological peculiarities. In the Traditional method, the second fermentation is conducted in small-volume glass bottles (normally 750 ml), and the bottles remain static in a horizontal position, with the lees decanted at the bottom of the bottle. Usually, a fining agent (clarifier) is added to facilitate the removal of the lees during the “remuage and dégorgement”. Conversely, in the Charmat method, the second fermentation occurs in large-volume pressure tanks, usually made of stainless steel. The tanks have an internal shaker that keeps the liquid homogeneous. Moreover, these wines are filtered before bottling and do not need the addition of clarifiers. Regarding ageing on lees (yeast cells and other precipitates), normally, the sparkling wines made by the Traditional method age for longer periods (more than one year) compared with those produced by the Charmat method (less than six months). However, extending the time of contact with the lees in the Charmat method is possible, currently named “long Charmat”.
It seems that, technically, the differences attributed to the method used during the second fermentation (prise de mousse or foaming) of sparkling wines are overestimated, as during this fermentation: (1) just 20 to 25 g/L of sugar is consumed, giving 1 to 1.5 % (v/v) ethanol; (2) aromatic precursors present in the grape juice were metabolised during the first fermentation, and are less available for further biotransformation; (3) yeast population is relatively low (≤ 108 cells/mL), and yeast aromatic contribution during ageing is controversial. Therefore, other factors before the second fermentation are much more significant in the overall “difference” currently attributed to the “sparkling wine method” used.
Over time, wine communication and marketing have emphasised “the better quality of Traditional sparkling wines” to the point that consumers disregard wines produced by other methods, even without trying them. Moreover, as happen in different wine categories, some wines are more prone than others to ageing and benefit more or less from this process. For this reason, and the commercial appeal, usually the best base wines, more suitable for ageing, are currently destinated to the Traditional method, leaving the younger and lighter wines to be used in the Charmat method. Given this fact, quantitative and qualitative comparisons between sparkling wine-making methods using commercial sparkling wines should be avoided. In this case, the variable “winemaking method” cannot be considered an independent variable as it is not directly associated with the quality of the final product. However, what would happen if one used the same base wine and inoculum in both methods and aged them for the same period? Considering this question, researchers evaluated sparkling wines produced on an industrial scale using the same base wine, yeast strain, and inoculum and fermented by Traditional and Charmat methods. To compare these wines, the researchers evaluated their physicochemical parameters, volatile composition, and sensory attributes.
In this study, researchers analysed and compared sparkling wines produced by the Traditional and Charmat methods using the same base wine, yeast strain, inoculum, and aged on the lees during the same periods. The sensory analysis confirmed the absence of evident differences in the results of the analyses of physicochemical and volatile compounds. In general, during the tests, more evaluators could identify differences in the first stages in which sensory analyses were performed. As the ageing time on the lees increase, fewer evaluators could differentiate between the sparkling wines. It was observed that more than half of the evaluators could not differentiate the samples in all stages. Based on this data, the researchers concluded that the method used for the second fermentation does not determine the eventual differences currently associated with sparkling wine produced by the Traditional and Charmat methods.
Cisilotto, B., Scariot, F. J., Schwarz, L. V., Mattos Rocha, R. K., Longaray Delamare, A. P., & Echeverrigaray, S. (2023). Are the characteristics of sparkling wines obtained by the Traditional or Charmat methods quite different from each other? . OENO One, 57(1), 321–331. https://doi.org/10.20870/oeno-one.2023.57.1.7313
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