IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 Influence of Potential Alcohol and pH Adjustment on Polyphenols and Sensory Characteristics of Red Wines Produced at Different Harvest Time Points

Influence of Potential Alcohol and pH Adjustment on Polyphenols and Sensory Characteristics of Red Wines Produced at Different Harvest Time Points

Abstract

Wine quality is influenced by grape maturity, typically monitored by measuring sugar content and acidity. However, environmental factors such as extreme weather or fungal infections can force winemakers to harvest earlier than desired. This study investigated whether sugar and pH adjustment used to increase potential alcohol and reduce the perception of acidity, can also compensate for immaturity in terms of phenolic extractability, composition, and related sensory attributes. Since anthocyanin and sugar accumulation profiles do not necessarily run parallel during grape ripening, it was important to study several harvest time points.
Wines were made from Pinot noir and Cabernet Sauvignon grapes harvested in 2019 at three different stages of grape maturity, in the range of 18-24 Brix. After bottling, phenolic analysis (HPLC-DAD/FD, LC-QToF-MS and spectrophotometry) and sensory evaluation revealed that adjustment of early-harvest must to pH 3.3 and 24.5 Brix enhanced the extraction of seed-associated phenolics such as monomeric catechins, and resulted in higher ratings of a green, herbaceous and ethereal aroma, rough astringency and a harsh mouthfeel. Adjustment did not significantly increase concentrations of skin-associated phenolics such as anthocyanins and polymeric pigments, and could therefore not compensate for a lack of color intensity. Wines made from the late-harvest grapes had significantly higher concentrations of anthocyanins and polymeric pigments and lower concentrations of monomeric catechins and procyanidins. This resulted in wines with a full body and high ratings in color intensity, dark fruit aroma, and smooth astringency. The data suggests that anthocyanins and polymeric pigments can be used as markers for grape maturity. Potential alcohol and pH adjustment could not change the phenolic composition and sensory perception of an early-harvest wine to mimic those of a late-harvest wine.

DOI:

Publication date: June 24, 2022

Issue: IVAS 2022

Type: Article

Authors

Feifel Sandra1, Weilack Ingrid2, Wegmann-Herr Pascal3, Weber Fabian2 and Durner Dominik1

1Weincampus Neustadt, Institute for Viticulture and Oenology, Dienstleistungszentrum Ländlicher Raum (DLR) Rheinpfalz, Breitenweg 71, 67435 Neustadt an der Weinstraße, Germany
2University of Bonn (Germany)
3Institute for Viticulture and Oenology, Dienstleistungszentrum Ländlicher Raum (DLR) Rheinpfalz, Breitenweg 71, 67435 Neustadt an der Weinstraße, Germany

Contact the author

Keywords

List of different keywords (keyword1, keyword2, keyword3)

Tags

IVAS 2022 | IVES Conference Series

Citation

Related articles…

Terroir traceability in grapes, musts and wine: results of research on Gewürztraminer and Sauvignon Blanc grape varieties in northern Italy

In the study of terroir, a separate analysis of its many component factors can be of great help in accurately identifying a vineyard’s natural elements that impact wine quality and typicity. This research used a dedicated pluri-disciplinary approach to investigate the ecological characteristics, including geology and geographical features, of 14 vineyards that produce Gewürztraminer and Sauvignon Blanc cultivars in the alpine Alto Adige DOC wine region. Both the geopedological method using Vineyards Geological Identity (VGI) and the new Solar Radiaton Identity (SRI) topoclimatic classification method were used to provide analytical measurements and qualitative/quantitative characterisations. In addition, wide-ranging targeted and untargeted oenological and chemical analyses were carried out on grapes, musts and wines to correlate the soils’ geomineral and physical conditions with the biochemical properties of their fruits and wines. The research identified strong correlations between vineyard geo-identity and wine biofingerprint, confirming a mineral traceability of strontium rubidium ratio and some minerals distinctive to the local geology, such as K, Ca, Ag, Ba and Mn.  The study also discovered that particular geomineral and physical soil conditions of the studied vineyards are related to the different amount of amino acids, primary varietal aromas and polyphenols found in grapes, musts and wines. The research confirmed that winemaking technologies support oenological quality, although in some cases, human practices can overpower certain characteristic elements in wine, erasing the typical imprint left by the vineyards’ natural terroir, which becomes less traceable. Terroir abiotic ecological factors and vineyard identity can be classified in detail using the new VGI and SRI analysis methods to discover interrelationships between geo-pedological and topoclimatic conditions that impact wine quality. These methods are also helpful in identifying which ecological elements are exclusive to a particular vineyard or wine sub-region.

Whole bunch fermentation: adding complexity, or just making ‘green’ wine?

Certain grape varieties contain negligible levels of isobutyl methoxypyrazine (IBMP) in grapes. However, it has long been known that grape stems

New tools for a visual analysis of vineyard landscapes?

A vineyard landscape is above all an area observed by someone, that is to say a physical entity perceved and represented by this person.

Le aree viticole storiche nel mondo: i loro vitigni, la loro protezione e la tipicità dei vini in esse ottenuti

Il tema da trattare si riferisce ai vari ecosistemi viticoli mondiali, ovviamente non facilmente sintetizzabili in una relazione. Sostanzialmente si richiama

New insights on thiol precursors catabolism by yeast during wine fermentation: identification of the N-Acetyl-L-Cysteine conjugate

Understanding the catabolism of thiol precursors is essential for understanding the revelation of varietal thiols in wine. For many years, knowledge of these precursors has been limited to the S-conjugates of glutathione, cysteine (Cys3SH) and the dipeptides g-GluCys and CysGly, without being able to explain the full origin of 3-sulfanylhexan-1-ol (3SH) in wines