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…

Progetto di zonazione delle valli di Cembra e dell’Adige. Analisi del comportamento della varietà Pinot nero in ambiente subalpino

Nel 1990 la Cantina LA VIS ha intrapreso un progetto di zonazione dei terreni vitati allo scopo di acquisire le conoscenze scientifiche atte a consentire il miglioramento delle qualità dei prodotti. Tale progetto si è articolato su di una superficie di 2000 ettari ubicati lungo l’asta fluviale del fiume Adige da Trento a Salorno e del torrente Avisio da Lavis a Segonzano.

SAVOIR: A project promoting innovative and effective prophylactic methods in viticulture, as part of the governmental plan to anticipate the withdrawal of plant protection products in France (PARSADA)

Faced with the likely withdrawal of commercial specialities from use in the short to medium term, France has decided to implement an ambitious action plan to anticipate and avoid withdrawal without alternative solutions. The French wine industry (cniv and ifv) has been heavily involved in this action to define priorities. faced with the risk of the withdrawal of multi-site fungicides (folpel, dithianon, copper) coupled with the probable reduction in single-site fungicide solutions, mildew and black rot have been identified as the priority uses.

Identification of aroma markers in amarone wines

Amarone is an Italian red wine produced in the Valpolicella area, in north-eastern Italy. Due to its elaboration with withered grapes, Amarone is a rather unique example of dry red wine. However, there is very limited data so far concerning the volatile composition of commercial Amarone wines, which also undergo a cask aging of 2-4 years before release. The present work aims at characterizing the aroma composition of Amarone and to elucidate the relationships between chemical composition and sensory characters. The analysis of 17 Amarone commercial wines from the same vintage (2015) was carried out by means of Gas Chromatography-Mass Spectrometry (GC-MS) and extracted by Solid Phase Extraction (SPE) and Solid Phase Micro Extraction (SPME). In addition, the sampled wines were subjected to a sensory evaluation in the form of sorting task.RESULTS: 70 volatile compounds were successfully identified and quantified, 30 of which were present in concentrations above their odor thresholds in all the samples. Using the odor activity value (OAV), the compounds that potentially contribute to Amarone perceived aroma are b-damascenone, ethyl and isoamyl acetate, ethyl esters (hexanoate, octanoate, butanoate, 3-methybutanoate), 4-ethyl guaiacol, 3-methylbutanoic acid, dimethyl sulfide (DMS), eugenol, massoia lactone, 1,4-cineol, TDN, cis/trans-whisky lactone. In certain samples, high OAVs were also observed for 4-ethyl phenol and 1,8-cineole.Results from the sorting task sensory analysis showed three clusters formed.

Drought responses in Chardonnay and Sauvignon blanc grapevine cultivars: Mechanistic insights and varietal contrasts

This study explored the responses of Chardonnay and Sauvignon blanc grapevine cultivars to water deficit across four years, uncovering their shared patterns and distinctive coping mechanisms. The research was conducted in a commercial vineyard located in Isla de Maipo, Chile. Various characterization approaches were employed including plant water potentials (), gas exchange measurements, shoot vulnerability curves, productivity assessments, and leaf cell water relations. Linear mixed models and sensitivity analyses were performed using various statistical methods to evaluate cultivar responses to water deficit. As the water deficit progressed, both cultivars displayed a parallel reduction in stomatal conductance, leaf turgor, and increased shoot embolism.

EVALUATION OF THE OENOLOGICAL POTENTIAL OF NEW RESISTANT VARIETIES MEETING TYPICAL BORDEAUX CHARACTERISTICS

Varietal innovation is a major lever for meeting the challenges of the agro-ecological transition of vi-neyards and their adaptation to climate change. To date, selection work has already begun in the Bordeaux region through the Newvine project. The aim of this project is to create new vine varieties with resistance to mildew and powdery mildew, adapted to the climatic conditions of the Bordeaux region and enabling the production of wines that are in line with consumer tastes and the expected typicity of Bordeaux wines.