Terroir 2016 banner
IVES 9 IVES Conference Series 9 Spontaneous fermentation dynamics of indigenous yeast populations and their effect on the sensory properties of Riesling

Spontaneous fermentation dynamics of indigenous yeast populations and their effect on the sensory properties of Riesling

Abstract

Varietal Riesling aroma relies strongly on the formation and liberation of bound aroma compounds. Floral monoterpenes, green C6-alcohols, fruity C13-norisoprenoids and spicy volatile phenols are predominantly bound to disaccharides, which are produced and stored in the grape berry during berry maturation. Grape processing aims to extract maximum amount of the precursors from the berry skin to increase the potential for a strong varietal aroma in the wine. Subsequent yeast selection plays an important part in this process. While Saccharomyces cerevisiae seems to be limited in their expression of glycosidase enzymes required to cleave and liberate the aroma compounds from their precursors, different non-Saccharomyces yeast genera show more prominence. Due to the infrequent and scarce occurrence of Saccharomyces cerevisiae in the vineyard and grape samples, many scientific findings report that spontaneous alcoholic fermentation is dominantly conducted by yeast strains originating from the winery environment rather than from the vineyard. However, recent advancements of modern genetic tools have elucidated site-specific microbiota on grapes from different vineyards and vintages. Their role in fermented wine has not yet been clarified.

This study aims to shed light on the roles of vineyard and winery microbiomes in wine fermentations in relation to fermentation dynamics, aroma formation and sensory perception. Riesling grapes from five different Riesling vineyards in the Pfalz region, Germany was picked aseptically during the 2015 vintage. Pilot-scale spontaneous fermentations of each of the individual vineyard with triplicates were conducted with aseptically managed winemaking. Fermentation progress was monitored by density measurements and FTIR-spectroscopy. Yeast population dynamics in the fermentations were monitored and identified with next-generation sequencing technology. Descriptive analysis of the wines was used to evaluate the changes in aroma and flavor sensory profiles.

Results show plausible promise in both the microbial difference occurring in the vineyard as well as clear impact of the winery-derived microbiome. Modulation of aroma and taste was observed and correlated with the occurrence of specific yeast species.

DOI:

Publication date: June 23, 2020

Issue: Terroir 2016

Type: Article

Authors

Kimmo Siren

Centre DLR RheinPfalz, Institute for Viticulture and Oenology

Contact the author

Keywords

Terroir, enology, Riesling, fermentation, indigenous yeast

Tags

IVES Conference Series | Terroir 2016

Citation

Related articles…

Spotted lanternfly, a new invasive insect in vineyards: is it a threat to grapevines?

The spotted lanternfly (SLF; Lycorma delicatula) is a phloem-feeding polyphagous insect invasive to the Eastern U.S.. Since its first detection in Pennsylvania (U.S.) in 2014, large infestations and economic damage (e.g., decreased yield, vine decline, greater pesticide use) have been reported in an increasing number of vineyards, threatening the sustainability and growth of the wine industry in infested regions. Our team has been investigating the impacts of SLF phloem-feeding on physiological processes, fruit production, juice, and wine composition of different grape cultivars, and also evaluated if the SLF can transmit important grapevine pathogens. In addition, we are working closely with stakeholders to better enumerate the economic damage caused by this pest. These findings will provide relevant information to grape and wine producers to help identify action thresholds and develop a more targeted integrated pest management program.

Preliminary steps of a protocol to isolate transcription factors bound to a specific DNA locus in grapevine using CRISPR-dCas9 system

Cis-acting regulatory elements are DNA sequences that can be bound by transcription factors to regulate the expression of genes in a condition-dependent and tissue-specific way. It is nowadays possible to search for DNA motives and sequences that a given transcription factor is binding or at least can, but it is still hard to have a glance at all the transcription factors that are contemporaneously located at the same locus. Inspired by an existing technique that uses the CRISPR-Cas system in mammal cells, we are trying to develop a protocol to study such regulation in Vitis vinifera. Using the highly sequence-specific binding capacity of a catalytically inactive Cas9 protein (dCas9), our idea is to set up a system to target a desired sequence and precipitate all the crosslinked proteins and distantly interacting chromatin at this locus and analyze them.

Zonazione dell’area viticola doc durello

Il lavoro di zonazione riveste un ruolo importante per capire le potenzialità e la vocazionalità di una specifica area viticola. La viticoltura dovrebbe essere vista in funzione dell’obiettivo enologico che si vuole realizzare e quindi particolare importanza riveste il risultato delle vinificazioni delle uve provenienti dai vigneti delle diverse aree della zona di produzione oggetto d’indagine. La zonazione dell’area a DOC Monti Lessini Durello ha preso in esame la varietà “Durella”, vitigno autoctono del territorio, che rappresenta la maggior parte della produzione vitivinicola della zona.

Use of artificial intelligence for the prediction of microbial diseases of grapevine and optimisation of fungicide application

Plasmopara viticola, the causal agent of downy mildew (DM), and Uncinula necator, the causal agent of powdery mildew (PM), are two of the main phytopathogenic microorganisms causing major economic losses in the primary sector, especially in the wine sector, by wilting bunches and leaves with a consequent decrease in the photosynthetic rate of the plant and in the annual yield. Currently, the most widespread methods for planning spraying are based on the 3-10 rule, which states that the first application should take place when: (i) the air temperature is greater than 10°C; (ii) shoots are equal or greater than 10 cm; and (iii) a minimum of 10 mm rainfall within 24–48 hours has occurred, or at the beginning of the bud break with periodic applications according to the manufacturer’s instructions.

Ultrastructural and chemical analysis of berry skin from two Champagne grapes varieties and in relation to Botrytis cinerea susceptibility

Botrytis cinerea is a necrotrophic pathogen that causes one of the most serious diseases of the grapevine (Vitis vinifera), grey mold or Botrytis bunch rot. In Champagne, the Botrytis cinerea disease leads to considerable economic losses for winemakers and wines exhibit organoleptic defaults.