IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 Significance of factors making Riesling an iconic grape variety

Significance of factors making Riesling an iconic grape variety

Abstract

Riesling is the iconic grape variety of Germany and accounts for 23% of the German viticulture acreage, which comprises 45% of the worldwide Riesling plantings. Riesling wines offer a wide array of styles from crisp sparkling wines to highly concentrated and sweet Trockenbeerenauslese or Icewines. However, its thin berry skin makes Riesling more vulnerable to detrimental environmental threats than other white wine varieties.

Trying to adapt Riesling to climate change we investigate how to mitigate premature Botrytis infections, the loss of quality and yield due to sunburn or increasing levels of TDN, which causes the unique petrol off-flavor. Weather variation from year to year necessitates an active acidity management, either diminishing acidity by skin maceration or use of lactic acid bacteria but also more recently lowering pH by ion exchange resins or malic acid producing yeast. A strong focus is to enhance intensity and diversity of Riesling aroma by viticultural and oenological measures, which are controlled by sophisticated chemical analysis including a measure of odorless precursors.

 Riesling is a highly transparent variety in respect to terroir, deviating strongly in odor and taste due to different bed rocks and soil types, micro climates and inclination of individual vineyards. Applying comprehensive stable isotope dilution analysis of volatiles and sensory evaluation we could demonstrate not only the sensory relevance of terroir, but also how stable these patterns were over five vintages and even individual winemaking measures. Using next generation gen- sequencing techniques to study spontaneous fermentations, we could also reveal the significant impact of site specific microbiomes.

 Riesling wines are highly acclaimed for their longevity due to their exciting balance of acidity and sweetness. Re-tasting terroir defined Riesling wines again after four years revealed the expected modification in sensory terms due to aging, but prove that the general differences among the specific terroir expressions were conserved through the maturation process.

 Many of these scientific puzzle pieces were successfully implemented by the Riesling producers over the last two decades and they succeeded to improve Riesling wines in each of its multitude of stylistic facets. However, it will be a challenge to preserve their unique and diverse characters in the course of progressive climate change

DOI:

Publication date: June 22, 2022

Issue: IVAS 2022

Type: Article

Authors

Ulrich Fischer¹*
¹Institute for Viticulture and Oenology, DLR Rheinpfalz, Breitenweg 71, 67435 Neustadt, Germany

Contact the author

Keywords

Riesling, aroma compounds and precursors, sensory evaluation, terroir, acidity management, ageing of wine

Tags

IVAS 2022 | IVES Conference Series

Citation

Related articles…

Microbial ecosystems in wineries – molecular interactions between species and modelling of population dynamics

Microbial ecosystems are primary drivers of viticultural, oenological and other cellar-related processes
such as wastewater treatment. Metagenomic datasets have broadly mapped the vast microbial species
diversity of many of the relevant ecological niches within the broader wine environment, from vineyard
soils to plants and grapes to fermentation. The data highlight that species identities and diversity
significantly impact agronomic performance of vineyards as well as wine quality, but the complexity
of these systems and of microbial growth dynamics has defeated attempts to offer actionable
tools to guide or predict specific outcomes of ecosystem-based interventions.

The aroma diversity of Italian white wines: a further piece added to the D-Wines project

The wide ampelographic heritage of the Italian wine grape varieties represents a richness in terms of biodiversity and potential market value.

Photoprotective extracts from agri-food waste to prevent the effect of light in rosé wines 

Light is responsible for adverse reactions in wine including the formation of unpleasant flavors, loss of vitamins or photodegradation of anthocyanins. Among them, the riboflavin degradation leads to the formation of undesirable volatile compounds, known as light-struck taste. These photo-chemical reactions could be avoided by simply using opaque packaging. However, most rosé wines are kept in transparent bottles due to different commercial reasons. Some agri-food waste extracts have been studied for their photoprotective action which turn to be highly correlated with phenolic content [1].

Effect of different pH values on the interaction between yeast mannoproteins and grape seed flavanols

The consequences of the global climate change in the vitiviniculture are revealed as a gap between phenolic and technological grape maturities, higher grape sugar concentration that leads to high wine alcohols levels, lower acidities and high pH values, among others. The unbalanced phenolic maturity caused in this scenario leads to harsh astringency and to instable colour of wines. Previous studies have reported that the addition of yeast mannoproteins (MPs) to wines may have positive effects on these two organoleptic properties due to their capability to interact with wine polyphenols [1]; however, studies about the effect of the pH on these interactions have not been carried out so far.

“Zonation”: interpretation and estimation of “Great zonation” (GZ) following the base methodology of “GRANDE FILIERA” (GF) (Great chain)

Dans des travaux précédents sur le zonage, on a traité de la « Grande Filière », du « terroir », du « territoire », de la «″Terra »″ (« Terre »”), des « Petits zonages ou sub-zonages », du « Grand Zonage », de la qualité (nous en avons classifié plus de quatre-vingt-dix), des « Grands Objectifs » (GO) de l’activité vitivinicole et des moyens utilisés pour les atteindre. Dans le « GRAND ZONAGE » (GZ) nous avons précisé que pour zoner, nous partons des aspects