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.

Download the PDF

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…

ASSESSMENT OF ‘DOLCETTO’ GRAPES AND WINES FROM DIFFERENT AREAS OF OVADA DOCG

Dolcetto (Vitis vinifera L.) is one of the traditionally cultivated varieties in Piedmont (north-east Italy). Dolcetto wines have long been associated with local consumption and they are little known internationally. In particular, the Ovada area (south-east Piedmont), even if it represents a small share of the regional PDO Dolcetto production, is one of the oldest and vocated territory, giving wine also suitable for aging. In this study, the basic composition and phenolic content of Dolcetto grapes for Ovada DOCG wines have been investigated in three different vintages (2020-2022), as well as the main aspects of the derived commercial and experimental wines (basic parameters, phenolics, volatile compounds, sensory properties).

Read More

Drought stress shapes the fungal microbiome of grapevine leaves: insights from DNA metabarcoding

Drought stress is an increasingly prevalent environmental challenge with implications for grapevine physiology and productivity, as well as for the microbiomes associated with grapevine tissues.

Read More

The use of plasma activated water in barrel disinfection: impact on oak wood composition

The use of barrels is a practice that improves the quality of wines. The porous structure of wood favors the accumulation of microorganisms that can deteriorate the quality of wines so that barrel cleaning and sanitizing treatments are essential. The burning of sulphur discs has been the most common practice in winemaking because ots biocide effect. Nevertheless, its effectiveness is still insufficient and it is harmful for human health.

Read More

New antibacterial peptides produced by Saccharomyces cerevisiae responsible for the inhibition of malolactic fermentation

In winemaking, several antimicrobial peptides (AMPs) produced by different strains of Saccharomyces cerevisiae were found to be responsible for the inhibition of malolactic fermentation (MLF) carried out by some strains of Oenococcus oeni. However, only two AMPs produced by one of the yeast strains studied were totally identified and their mechanism of action was described. In an attempt to identify new AMPs, a 5-10 kDa peptidic fraction produced by an oenological strain of S. cerevisiae and previously shown to strongly inhibit MLF carried out by a strain of O. oeni was further purified.

Read More

Innovations in the use of bentonite in enology: interactions with grape and wine proteins, colloids, polyphenols and aroma compounds.

The use of bentonite in oenology rounds around the limpidity and the stability that determine consumer acceptability. As a matter of fact, the haze formation in wine reduces its commercial value and makes it unacceptable for sale. Stabilization treatments are, therefore, essential to ensure a long-time limpidity and to forecast the formation of deposits in the bottle. Bentonite that is normally used in oenology for clarifying-fining purpose, shows a natural clay-based mineral structure allowing it to swell and to jelly in water and hence in must and wine.

Read More