Terroir 1996 banner
IVES 9 IVES Conference Series 9 La vinificación de las uvas aromáticas: Moscateles y Malvasías

La vinificación de las uvas aromáticas: Moscateles y Malvasías

Abstract

Las uvas aromáticas se pueden dividir en dos clases, Moscateles y Malvasías, dependiendo del hecho de que el linalol o el geraniol, respectivamente, sean los alcoholes terpénicos monohidroxilados que predominan en el jugo de la uva. Dentro de cada clase existen numerosas subclases que se diferencian por las relaciones entre los otros alcoholes terpénicos mono y dihidroxilados, en forma libre y glicosilada. Otra diferencia entre los Moscateles y las Malvasías es la cantidad de compuestos terpénicos libres del mosto, (los terpenos del hollejo, en las dos clases, se encuentran casi en su totalidad como formas glicosiladas) que puede ser alto como en el caso del Moscatel (linalol, óxido trans piránico del linalol, 2,6-dimetil-3,7-octadien-2,6-diol) o mas bién bajo como en el caso de las Malvasías (geraniol, 2,6-dimetil-3,7-octadien-2,6-diol), mientras que en los hollejos es una característica común a las dos clases la presencia de elevadas cantidades de nerol y de geraniol en forma glicosilada. La composición terpénica de las dos variedades condiciona, además del aroma del vino final, la tecnología de producción.En Italia con el “Moscato bianco” y con las Malvasías (“Malvasia di Casorzo”, “Malvasia di Castelnuovo don Bosco”, esta última en muchos aspectos parecida a los Moscateles, “Brachetto d’Acqui”, que son todas variedades tintas) se preparan dos tipos de vino: uno espumoso y uno no espumoso. El primero se caracteriza por un contenido alcohólico de aproximadamente un 7%y una concentración de azúcares de aproximadamente 70 g/L y el segundo por un grado alcohólico del 5 % y una cantidad de azúcares variable dependiendo de los gustos del productor.En la vinificación del “Moscato bianco” se utiliza solo el mosto (una eventual criomaceración no conlleva un aumento sensible en compuestos terpénicos), que es rico de linalol que no resulta ni absorbido ni metabolizado por las levaduras, mientras que en el caso de las Malvasías tintas, para cuya vinificación se utilizan también los hollejos, el geraniol, practicamente el único alcohol terpénico monohidroxilado presente en el mosto, es metabolizado parcialmente por las levaduras y en parte reducido a citronellol y estos dos compuestos, además del nerol, son transformados en derivados acetilados. Además, a causa de las elevadas cantidades de glucosa que se encuentran en el mosto durante toda la fase de preparación de los vinos de estas variedades, los enzimas glicosidásicos, del mosto o de las levaduras, no pueden transformar en los respectivos aglicones los glicósidos del nerol y del geraniol presentes en el mosto, que quedan, por lo tanto, en forma glicosilada, es decir, no aromática, en el vino final. Las técnicas tradicionales de vinificación establecen, para la extracción del color y de los compuestos terpénicos de los hollejos de las Malvasías tintas, continuos remontados cuando la fermentación todavía no ha empezado, o una fermentación parcial en presencia de los hollejos. Estas dos técnicas son insuficientes sea para extraer la gran cantidad de glicósidos del nerol y del geraniol de los hollejos, sea para hidrolizar los glicósidos terpénicos. En este trabajo se presenta una nueva técnica de vinificación, que favorece la extracción y la hidrólisis de los compuestos terpénicos de los hollejos de las Malvasías tintas y que incrementa sensiblemente la intensidad del aroma y la calidad de los vinos que se obtienen con esta variedad.

DOI:

Publication date: February 24, 2022

Issue: Terroir 2000 

Type: Article

Authors

Rocco Di Stefano*, Emilia García Moruno* and Monica Ribaldone**

*Istituto Sperimentale per l’Enologia, via P. Micca 35 — 14100 Asti (Italia)
**Consorzio per la tutela del Brachetto

Tags

IVES Conference Series | Terroir 2000

Citation

Related articles…

Permanent cover cropping with reduced tillage increased resiliency of wine grape vineyards to climate change

Majority of California’s vineyards rely on supplemental irrigation to overcome abiotic stressors. In the context of climate change, increases in growing season temperatures and crop evapotranspiration pose a risk to adaptation of viticulture to climate change. Vineyard cover crops may mitigate soil erosion and preserve water resources; but there is a lack of information on how they contribute to vineyard resiliency under tillage systems. The aim of this study was to identify the optimum combination of cover crop sand tillage without adversely affecting productivity while preserving plant water status. Two experiments in two contrasting climatic regions were conducted with two cover crops, including a permanent short stature grass (P. bulbosa hybrid), barley (Hordeum spp), and resident vegetation under till vs. no-till systems in a Ruby Cabernet (V. vinifera spp.) (Fresno) and a Cabernet Sauvingon (Napa) vineyard. Results indicated that permanent grass under no-till preserved plant available water until E-L stage 17. Consequently, net carbon assimilation of the permanent grass under no-till system was enhanced compared to those with barley and resident vegetation. On the other hand, the barley under no-till system reduced grapevine net carbon assimilation during berry ripening that led to lower content of nonstructural carbohydrates in shoots at dormancy. Components of yield and berry composition including flavonoid profile at either site were not adversely affected by factors studied. Switching to a permanent cover crop under a no-till system also provided a 9% and 3% benefit in cultural practices costs in Fresno and Napa, respectively. The results of this work provides fundamental information to growers in preserving resiliency of vineyard systems in hot and warm climate regions under context of climate change.

Impact of climate variability and change on grape yield in Italy

Viticulture is entangled with weather and climate. Therefore, areas currently suitable for grape production can be challenged by climate change. Winegrowers in Italy already experiences the effect of climate change, especially in the form of warmer growing season, more frequent drought periods, and increased frequency of weather extremes.
The aim of this study is to investigate the impact of climate variability and change on grape yield in Italy to provide winegrowers the information needed to make their business more sustainable and resilient to climate change. We computed a specific range of bioclimatic indices, selected by the International Organisation of Vine and Wine (OIV), and correlated them to grape yield data. We have worked in collaboration with some wine consortiums in northern and central Italy, which provided grape yield data for our analysis.
Using climate variables from the E-OBS dataset we investigate how the bioclimatic indices changed in the past, and the impact of this change on grape productivity in the study areas. The climate impact on productivity is also investigated by using high-resolution convection-permitting models (CPMs – 2.2 horizontal resolution), with the purpose of estimating productivity in future emission scenarios. The CPMs are likely the best available option for this kind of impact studies since they allow a better representation of small-scale processes and features, explicitly resolve deep convection, and show an improved representation of extremes. In our study, we also compare CPMs with regional climate models (RCMs – 12 km horizontal resolution) to assess the added value of high-resolution models for impact studies. Further development of our study will lead to assessing the future suitability for vine cultivation and could lead to the construction of a statistical model for future projection of grape yield.

austrianvineyards.com: online viewer of all designations of Austrian wine

To digitally record and present all the origins of Austrian wines in the same perfect and clear way was the motivation for the Austrian Wine Marketing Board (Austrian Wine) to start with the project in 2018. In June 2021 the results were presented to the public in an online viewer showing all the designations of Austrian wine, available at https://austrianvineyards.com in a largely barrier-free manner. The online viewer provides tailored individual maps fitted to the respective zoom level. The smallest unit of wine-origins in Austria is called Ried and is displayed in a plot-specific manner highlighting areas under vine. Information on the Ried include administrative district, winegrowing municipality, cadastral municipality, large collective vineyard site, specific winegrowing region, generic winegrowing region, winegrowing area and, in many cases, an illustrative picture. Complementary data on the size, elevation (minimum-maximum), orientation (in 8 sectors plus flat) and gradient (minimum, maximum, average) are based on the area under vine according to the EU’s Integrated Administration and Control System. Additional information covers climate data. The diagrams are taken from the monthly breakdown of data in the annals of the Central Institute for Meteorology and Geodynamics, Austria provide a display of values for air temperature, precipitation, and sunshine hours for the reference year and the long-term average. Seasonal aggregated data on temperature, precipitation, and sunshine hours complete the display. Short descriptions with emphasis on geology and soil, field name in historical maps, etymology of the denomination, and main planted variety complements the available information for the main designations in the online viewer. These descriptions are compiled by winegrowers, geologists, historians, and journalists. All the information and data can be extracted to a pdf-file. Printed vineyard maps are also available. Missing content regarding wine origins in Styria will be completed in winter 2021/22.

Biodiversity in the vineyard agroecosystem: exploring systemic approaches

Biodiversity conservation and restoration are essential for guarantee the provision of ecosystem services associated to vineyard agroecosystem such as climate regulation trough carbon sequestration and control of pests and diseases. Most of published research dealing with the complexity of the vineyard agroecosystems emphasizes the necessity of innovative approaches, including the integration of information at different temporal and spatial scales and development of systemic analysis based on modelling. A biodiversity survey was conducted in the Franciacorta wine-growing area (Lombardy, Italy), one of the most important Italian wine-growing regions for sparkling wine production, considering a portion of the territory of 112 ha. The area was divided into several Environmental Units (EUs), defined as a whole vineyard or portion of vineyard homogenous in terms of four agronomic characteristics: planting year, planting density, cultivar, and training system. In each EU a set of compartments was identified and characterised by specific variables. The compartments are meteorology, morphology (altitude, slope, aspect, row orientation, and solar irradiance), ecological infrastructures and management. The landscape surrounding EU was also characterised in terms of land-use in a buffer zone of 500 m. For each component a specific methodology was identified and applied. Different statistical approaches were used to evaluate the method to integrate the information related to different compartments within the EU and related to the buffer zone. These approaches were also preliminarily evaluated for their ability to describe the contribution of biodiversity and landscape components to ecosystem services. This methodological exploration provides useful indication for the development of a fully systemic approach to structural and functional biodiversity in vineyard agroecosystems, contributing to promote a multifunctional perspective for the all wine-growing sector.

A multidisciplinary approach to evaluate the effects of the training system on the performance of “Aglianico del Vulture” vineyards

Vineyards are complex agro-ecosystems with high spatial and temporal variability. An efficient training system may counteract the adverse effects of this variability. Moreover, considering the climate change issues, choosing an efficient training system that enhances water use and protects the vines from radiative thermal stress has become a priority for the farmers. A multidisciplinary approach that assesses the soil-crop-yield-wine relationships of vineyards in a distributed and holistic way could bring added knowledge on the behavior of the different training systems. This ongoing research aimed to implement a multidisciplinary approach to study the behavior of “Aglianico del Vulture” grapevines trained with two different systems: a spurred cordon (SC) and an “Alberello in parete” (AL), grown in a high-quality wine production area of Basilicata region (Italy). The approach merged several methods and scales of soil, ecophysiology, must/wine quality, and spectral data collection to assess the influence of the training system. Homogeneous zones (HZs) in both training systems were defined through a procedure based on geomorphological classification, unmanned aerial vehicles (UAV) images analysis, and a traditional soil survey supported by geophysical scanning. During the 2021 season, TDR probes monitored soil water content, while grapevine health status was assessed using eco-physiological measurements (LWP, chlorophyll content, PSII photosynthetic efficiency, LAI, and point-based field spectroscopy). These grapevine in-vivo measurements validated the spectral vegetation indexes (NDVI, RENDVI, CVI, and TVI) derived from the UAV multispectral imagery, which monitored the grapevine status in a distributed and non-invasive way. Grape yield, quality of berries, must and wine were measured to assess the effects of the training systems. The first experimental year results showed the variability of the vineyards and revealed relationships among soil parameters, crop characteristics, and vegetation indices of the SC and AL training systems. This multidisciplinary study could bring new insights into the vineyard training system’s effects on grape yield and wine quality.