Coline Leriche, Anne Flesch,* Stéphanie Rollero, Arnaud Delaherche, Maryam Ehsani, Gabriela Montandon, and Etienne Dorignac
*Fermentis, 137 rue Gabriel Péri, 59700 Marcq-en-Baroeul, France (a.flesch@fermentis.lesaffre.com)

Fermentative microorganisms are affected by the physiochemical characteristics of their environment. In winemaking, temperature and yeast nutrition play a major role in wine quality and sensory profile. They affect aroma production during fermentation and temperature also influences fermentation duration, which can modulate aroma content. While many studies focus on temperature and nitrogen effects, few examine the combination between these factors, including the type and timing of nutrient addition.

We studied the simultaneous effect of three factors on fermentation kinetics, aroma production during fermentation, and sensory profile: i. temperature of fermentation (T), ii. yeast assimilable nitrogen (YAN), iii. type and moment of nutrient addition (N), in a Burgundy Chardonnay wine.

To do so, a Box-Behnken experimental design was used to determine 14 treatments to be studied, with a triplicate in the medium case. Studied temperatures were 12, 16, and 20°C, the ratio YAN/Sugar (mg N/g S) varied from 0.8, 1 to 1.2 in model N-deficient or excess musts, and nutrition was varied using organic or mineral N-rich nutrient, equally used at the pitching moment or at 30% fermentation. Fermentations took place in 20-L temperature-controlled vessels, on a Chardonnay must from Burgundy inoculated with 20 g/hL of yeast, and malolactic fermentation was blocked to avoid tasting bias.

Kinetics were monitored during fermentation and classical fermentative aromas were analyzed after verifying the implantation of the yeast in the must. Descriptive profile tasting was conducted by a panel of 10 well-trained professionals familiar with Chardonnay from Burgundy. This study presents a scientific exploration of fermentation management through temperature and nutrition regimes and illustrates the potential leverage of yeast to produce quality wines.

Funding Support: Fermentis, division of S.I. Lesaffre