The Impact of Must Nutrients and Yeast Strain on the Aromatic Quality of Wines for Cognac Distillation

Charlie Guittin,Faïza Maçna,Jean-Marie Sablayrolles,Jean-Roch Mouret,Isabelle Sanchez,Adeline Barreau,Vincent Farines,Xavier Poitou

doi:10.3390/fermentation8020051

Abstract

In order to understand the influence of nitrogen and lipid nutrition on the aromatic quality of wines for cognac distillation, we developed a transdisciplinary approach that combined statistical modeling (experimental central composite design and response surface modeling) with metabolomic analysis. Three Saccharomyces cerevisiae strains that met the requirements of cognac appellation were tested at a laboratory scale (1 L) and a statistical analysis of covariance was performed to highlight the organoleptic profile (fermentative aromas, terpenes, alcohols and aldehydes) of each strain. The results showed that nitrogen and lipid nutrients had an impact on the aromatic quality of cognac wines: high lipid concentrations favored the production of organic acids, 1-octen-3-ol and terpenes and inhibited the synthesis of esters. Beyond this trend, each yeast strain displayed its own organoleptic characteristics but had identical responses to different nutritional conditions.

Highlights

Cognac is a French protected designation of origin (PDO) whose quality is recognized worldwide
Yeast assimilable nitrogen (YAN) and lipids, which are the main nutrients in grape musts [4], can have a significant impact on the production of volatile compounds
A “weight” was assigned to each parameter; a classification of these two parameters according to their influence on the synthesis of each volatile compound or on the fermentative parameters could be performed

Summary

Introduction

Cognac is a French protected designation of origin (PDO) whose quality is recognized worldwide This wine spirit is obtained after a double distillation using almost exclusively the Ugni blanc grape variety. Fermentative aromas (higher alcohols, esters, aldehydes, acetyls, fatty acids, etc.) are synthesized by yeast during alcoholic fermentation [2] while varietal aromas, such as terpenes or aliphatic aldehydes, originate from the grape berries. For both these aromatic classes, the proportions found in wines are influenced, modified or even disturbed during alcoholic fermentation by different environmental parameters [3]. Most studies have concluded that phytosterols have an overall positive effect on higher alcohol synthesis and a negative impact on ester synthesis [9,18,19,20]

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Conclusion