 IVES 9 IVES Conference Series 9 Macrowine 9 Macrowine 2021 9 Chemical diversity of 'special' wine styles: fortified wines, passito style, botrytized and ice wines, orange wines, sparkling wines 9 What is the best time to harvest grapes destined for withering? Ripeness and dehydration length affect phenolic composition of Nebbiolo grapes

What is the best time to harvest grapes destined for withering? Ripeness and dehydration length affect phenolic composition of Nebbiolo grapes

Abstract

AIM: Sfursat di Valtellina is a DOCG reinforced wine produced in Valtellina from partially withered red grapes of Vitis vinifera L. cv. Nebbiolo. The grape ripeness degree and the dehydration process strongly influence the physicochemical characteristics of grapes [1, 2, 3]. In particular, grape skin and seeds contain several classes of phenolic compounds strictly associated with red wine quality, which are significantly affected by these factors [4]. The aim of this research is to assess the combined influence of different ripeness levels and withering rates on the standard chemical composition and phenolic profile of winegrape in order to provide new insights and approaches to the management of withering, searching for the valorization of grape potentialities.

METHODS: During a two-year study (vintages 2019 and 2020) three binomials have been tested: early harvest/long withering (EL), medium-term harvest/medium-term withering (MM) and late harvest/short withering (LS). Grape samples of cv. Nebbiolo from two vineyards at different locations (Valtellina upper and lower valley) were harvested and placed into a typical ‘fruttaio’ dehydration room, following the wine type designation guidelines. Grape must composition, mechanical parameters and extractable phenolic profiles (total polyphenols, total anthocyanins, total flavonoids and methylcellulose tannin assay) of grape skins and seeds were studied before and after the withering process.

RESULTS: At the end of withering, EL thesis showed the highest values of sugars and acidity, and the lowest pH. The content of total polyphenols, flavonoids, and tannins in seeds showed a decreasing trend by leaving the grapes on the plant longer, whereas their impact increased considerably after withering with respect to fresh samples, due to berry dehydration. Instead, the skin phenolic compounds were less influenced by harvest period, but their concentrations on grape weight increased after withering. Skin extractable anthocyanins experienced a distinct trend for the two vineyards studied: their concentration increased in withered samples from the upper-valley vineyard and decreased in those from the lower-valley. The grapes mechanical properties may have influenced this aspect, as previously demonstrated [5]. Finally, the differences highlighted between the three binomials studied were more noticeable in vintage 2019 rather than in 2020, probably due to the higher rainfall in the final stage of grape ripening in vintage 2020.

CONCLUSIONS:

In this research, the combined effect of ripeness degree and withering process length have been studied. The results obtained shows that these two variables can be modulated according to the desired oenological objective. In general, early/medium harvest and long/medium withering gave the best results, particularly for seeds polyphenols, although the vineyard location and the weather conditions of the year influenced the withered grape phenolic characteristics.

DOI:

Publication date: September 16, 2021

Issue: Macrowine 2021

Type: Article

Authors

Giulia Scalzini

University of Torino, Italy,Maria Alessandra PAISSONI, University of Torino, Italy Simone GIACOSA, University of Torino, Italy Danilo DROCCO, Cantina Nino Negri, Italy Aldo RAINOLDI, Casa Vinicola Aldo Rainoldi, Italy Diego ORTIZ JACOB, University of Torino, Italy Giovanni BITELLI, University of Torino, Italy Susana RÍO SEGADE, University of Torino, Italy Vincenzo GERBI, University of Torino, Italy Luca ROLLE, University of Torino, Italy

Contact the author

Keywords

postharvest withered grapes, phenolic compounds, withering process, sfursat di valtellina, sforzato, reinforced wines, special wines

Citation

Can yeast cells sense other yeasts beyond competition interactions?

The utilization of non-Saccharomyces yeasts in the wine industry has increased significantly in recent years. Alternative species need commonly be employed in combination with Saccharomyces cerevisiae to avoid stuck fermentation, or microbial spoilage. The employment of more than one yeast starter can lead to interactions between different species with an impact on the outcome of wine fermentation. Previous studies[1] demonstrated that S. cerevisiae elicits transcriptional responses with both shared and species-specific features in co-culture with other yeast species.

Vinhos de talha: to pitch or not to pitch

In Alentejo, south of Portugal there is a traditional way of fermenting wines in clay vessels, known as “Vinhos de Talha”. Clay vessels were traditionally impermeabilized using pine pitch, creating a barrier between the fermenting must and the clay. Due to this unusual production technology that uses of clay vessels, instead of inox or wood vessels, “Vinhos de Talha” present unique characteristics increasingly appreciated by national and international consumers when compared with wine obtained by the said traditional methods of winemaking. Although the positive consumers feedback, there is little literature about the physical-chemical characteristics of these wines (Martins et al, 2018; Cabrita et al, 2018). This work aims to characterize the volatile composition of white wines produced in clay vessels with different coatings and to contribute to the knowledge and preservation of these wines that are a unique cultural heritage. Wine samples were produced during 2019 vintage from white grapes, using the traditional technology associated to these wines.

Merano Wine Festival 2020

IVES was a partner of the Merano Wine Festival (innovation section), a digital event held from 6 to 10 November 2020. During this festival participants attended scientific conferences on cutting-edge topics for the wine industry. Some of the topics covered have been selected from our journals

Towards the understanding of wine distillation in the production of brandy de Jerez. Chemical and sensory characterization of two distillation methods: continuous and batch distillation

Brandy de Jerez (BJ) is a spirit drink made exclusively from spirits and wine distillates and is characterized by the use of casks for aging that previously contained Sherries. The quality and sensory complexity of BJ depend on the raw materials and some factors: grape variety, conditions during processing the wine and its distillation, as well as the aging in the cask. Therefore, the original compounds of the grapes from which it comes are of great interest being in most cases the Airén variety. Their relationship with the quality of the musts and the wines obtained from them has been studied (1) and varies each year of harvest depending on the weather conditions (2).

Definition and planning of viticultural landscapes case study in the “Côtes du Rhône Gardoises”

Les préoccupations actuelles autour des paysages viticoles vont au-delà des clichés promotionnels développés par les stratégies marketing. En effet, les paysages sont aujourd’hui au cœur d’une demande sociale croissante qui se traduit par différentes lois (la loi paysage de 1993, le paysage reconnu comme patrimoine commun de la nation par la loi n°95-101, la création du Conseil national du paysage par arrêté du 8/12/2000).