Abstract
Adequate yeast assimilable nitrogen (YAN) concentration is necessary for successful wine fermentation; therefore, supplementing musts with nitrogen (N) is a common industry practice. In the Finger Lakes region of New York, Riesling juice (Vitis vinifera L.) often has YAN concentrations below the 140 mg/L considered a practical minimal limit. However, little research exists that has confirmed N requirements for cool-climate cultivars and conditions. To test the influence of juice N concentration on desirable sensory characteristics, a Riesling juice of 20 Brix and 130 mg/L initial YAN was supplemented with diammonium phosphate to increase YAN to 180, 250, and 300 mg/L. Each supplemented fraction and the unaltered control were inoculated with three different Saccharomyces cerevisiae yeast strains: EC1118 and W15 (Lallemand), and Côte des Blancs (Red Star). The control concentration of 130 mg N/L was enough for these three yeast strains to complete fermentation, and further supplementation improved fermentation kinetics only for EC1118. N supplementation affected the concentration of eight of the 10 select volatile compounds analyzed in at least one of the yeast strains. Of these, the concentration of most esters increased with N supplementation, with the exception of ethyl cinnamate, which decreased. Concentrations of the higher alcohols 1-hexanol and 2-phenylethanol decreased, and decanoic acid increased, with increased N. Linalool and 1,1,6-trimethyl-1,2-dihydronaphthalene, two volatiles associated with “varietal character” in Riesling, were not affected. In a preference-ranking test, sensory panelists preferred the unsupplemented control (130 mg N/L) over the supplementation treatments for wines fermented with EC1118. No difference in preference was found for the W15 and Côte des Blancs treatments.
- Received September 2017.
- Revision received April 2018.
- Revision received September 2018.
- Accepted October 2018.
- Published online April 2019
- ©2019 by the American Society for Enology and Viticulture
Sign in for ASEV members
ASEV Members, please sign in at ASEV to access the journal online.
Sign in for Institutional and Non-member Subscribers
Log in using your username and password
Pay Per Article - You may access this article (from the computer you are currently using) for 2 day for US$10.00
Regain Access - You can regain access to a recent Pay per Article purchase if your access period has not yet expired.