Thesis
Influence of Sugar and Nitrogen on Alcohol Reduction in Wine Sequentially Inoculated with Metschnikowia Pulcherrima and Saccharomyces Cerevisiae
Washington State University
Master of Science (MS), Washington State University
05/2025
DOI:
https://doi.org/10.7273/000007327
Abstract
Alcohol concentrations in wine have risen due to longer grape ripening periods, which have been implemented to meet the consumer’s preference for richer and fruitier wine. One consequence of this practice is that grapes are harvested with elevated sugar contents which, in turn, increases the amount of alcohol produced during fermentation. Higher amounts of alcohol can result in higher tax rates, unappealing sensory profile, and dislike by health-conscious consumers. The present study aims to reduce alcohol concentrations by sequentially inoculating Metschnikowia pulcherrima followed by S. cerevisiae, and to define must composition that will support a sequential fermentation. To accomplish this, grape must and synthetic grape juice medium (SGJM) were adjusted or prepared as follows: (1) Cabernet Sauvignon must containing 25˚, 28˚, or 31˚ Brix soluble solids and a total of 220, 250 or 280 mg N/L yeast assimilable nitrogen (YAN) respectively; (2) SGJM prepared with YAN (40 or 280 mg N/L) and soluble solids (24˚, 27˚, or 30˚Brix) as variables; (3) High YAN SGJM prepared with 450 mg N/L and either 24˚, 27˚, or 30˚Brix; (4) SGJM prepared with 0, 1, or 100 μg/L pantothenic acid. In
experiments, M. pulcherrima P01A016 was inoculated on day 0. S. cerevisiae was inoculated on day 4 in all experiments except the fourth experiment where it was not introduced. The sequentially inoculated SGJM treatment containing 40 mg N/L and 24˚Brix had 0.7% (v/v) less alcohol than the same medium singly inoculated. No other sequentially inoculated treatment reached dryness and had less alcohol than the singly inoculated treatment. Many treatments ≥27˚Brix failed to reach dryness, likely due to insufficient nutrition. In the Cabernet Sauvignon experiment, sequentially inoculated wines contained 0.177, 0.181, or 0.287 g/L less acetic acid than singly inoculated wines. Pantothenic acid did not benefit M. pulcherrima’s growth or metabolism. Overall, this experiment highlights the need for proper yeast nutrition to complete fermentation in a wine sequentially inoculated for alcohol reduction.
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Details
- Title
- Influence of Sugar and Nitrogen on Alcohol Reduction in Wine Sequentially Inoculated with Metschnikowia Pulcherrima and Saccharomyces Cerevisiae
- Creators
- Jonathan David Brumley
- Contributors
- Charles G Edwards (Co-Chair)Meijun Zhu (Co-Chair)G. Todd Vanek (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- School of Food Science
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Number of pages
- 98
- Identifiers
- 99901221252801842
- Language
- English
- Resource Type
- Thesis