Over the last decades, the average alcohol content of wine has increased due to climate change and consumer preferences for particular wine styles that resulted in increased grape sugar levels at harvest. Therefore, alcohol reduction is a current challenge in the winemaking industry. Among several strategies under study, the use of non-conventional yeasts in combination with Saccharomyces cerevisiae plays an important role for lowering ethanol production in wines nowadays.
Project layout
In the present work, 33 native non-Saccharomyces strains were assayed in sequential culture with a S. cerevisiae wine strain to determine their potential for reducing the alcohol content in Malvar white wines.
Results
- Four of the non-Saccharomyces strains (Wickerhamomyces anomalus 21A-5C, Meyerozyma guilliermondii CLI 1217, and two Metschnikowia pulcherrima (CLI 68 and CLI 460)) studied in sequential combination with S. cerevisiae CLI 889 were best able to produce dry wines with decreased alcohol proportion in comparison with one that was inoculated only with S. cerevisiae.
- These sequential fermentations produced wines with between 0.8% (v/v) and 1.3% (v/v) lower ethanol concentrations in Malvar wines, showing significant differences compared with the control.
- In addition, these combinations provided favourable oenological characteristics to wines such as high glycerol proportion, volatile higher alcohols, and esters with fruity and sweet character.
Significance of the study
This study confirms the results from many previous studies which demonstrated that the use of non-Saccharomyces yeasts, in combination with S. cerevisiae in a sequential inoculation strategy, can lower the final alcohol concentrations in wines. These non-Saccharomyces yeasts can at the same time also contribute positively to the aromatic complexity of wines. Careful attention should be paid to volatile acidity production by some non-Saccharomyces yeasts that could potentially have a negative effect on wine quality. This potential problem can be overcome with the use of commercially available non-Saccharomyces yeasts that are selected based on their low production of volatile acidity.
Reference
GarcÃa, M.; Esteve-Zarzoso, B.; Cabellos, J.M.; Arroyo, T. Sequential Non-Saccharomyces and Saccharomyces cerevisiae Fermentations to Reduce the Alcohol Content in Wine. Fermentation 2020, 6, 60. https://doi.org/10.3390/fermentation6020060
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