Terroir 1996 banner
IVES 9 IVES Conference Series 9 Ripening characterization and modelling of Listan negro grape in Spain using a regression analysis

Ripening characterization and modelling of Listan negro grape in Spain using a regression analysis

Abstract

The professional winegrower usually selects the harvest date considering several elements, such as the vine stem and berry colour, the flavour, appearance and grain elasticity. Nowadays these elements have turned old fashioned.
Other professionals take into account the weather or even manpower availability, so it is mainly random which determines wine quality, as this depends on the raw material (quality) characteristics.
In order to palliate these practice posible negative effects, this work was based on the simple mathematical equation obtention which characterized the ripening of the most common grape variety at Tacoronte-Acentejo vineyard area to give both the winegrower and the oenologist a simple instrument to find out the best harvest date or to know the value of each traditional parameter according to the weather.
This work was done during the season from 1994 to 1998, in the period that starts with the verasion and ends with the ripening process. During this period samples were taken weekly. About ten grains by vine stem were taken from a whole of fifty, which were previously selected in vineyards grown in different parts of the wine region.
Once they were in the laboratory and after getting the sample ready to obtain the grape must, multiple physicochemical analyses were done, from which we stand out the following ones: one hundred berry weight, total sample weight, total volume, grape must yield, soluble solids, probable alcoholic rate, pH, total acidity, tartaric acid, malic acid, bound and free volatile compounds (free and potentially volatile monoterpene grape flavourings), sodium, potassium, copper, iron, colour indicator parameters, from which only three have been used in this experiment, the sugar content given as probable alcoholic rate, pH and total acidity analysed using the Standard Methods.
After the systematic observation of the ripening curve lines, similar evolutive tendencies are found in the three analysed parameters. This tendency has been studied by comparing the curved line behaviour to a straight line, using a computerized calculation programme obtaining like this the slope, the ordinate in the origin and the coefficient of correlation r2 in each case. The equations found are of the type y = a + bx, were “y” represents the value of the physicochemical studied parameter and “x” the day from the verasion. The ordinate in the origin “a” will be the studied parameter value at the moment in which the first sample was taken, that is to say, in the verasion. Slope “b” indicates the studied parameter daily increase.
We have also found regression lines which allow the harvest date calculation for the probable alcoholic rate determined with 0,12 alcoholic / day slope for 500 m high vineyards areas or even higher. We have also established a linear pH relationship with the days up to the harvest, which depends on the vineyard height and a similar regression for the acidity has also been found.
Thus, knowing each parameter prediction equation, the winegrower will be able to know his harvest conditions. He will also be able to know the time left to obtain each analytical parameter wished value and so, the best optimum harvest date with more than a 90 % reliability.

DOI:

Publication date: February 24, 2022

Issue: Terroir 2000

Type: Article

Authors

García Fernández, M.J., González Mendoza, L.A., Pomar García, M.

Departamento de Ingeniería Química y Tecnología Farmacéutica
Facultad de Química. Universidad de La Laguna
Avda. Astrofísico Francisco Sánchez, s/n

Tags

IVES Conference Series | Terroir 2000

Citation

Related articles…

Grapevine sensitivity to fungal diseases: use of a combination of terroir cartography and parcel survey

In front of the economic interest and seeking to respect their environment, the wine growers move gradually towards a policy of reasoning their plant health protection. This is why, starting from epidemiologic studies on grapevine pathogens, forecasting models of the risks are developed by research and experimentation bodies.

A spatial explicit inventory of EU wine protected designation of origin to support decision making in a changing climate

Winemaking areas recognized as protected designations of origin (PDOs) shape important economic, environmental and cultural values that are tied to closely defined geographic locations. To preserve wine products and wine-growing practices adopted in different PDOs these areas are strictly regulated by legal specifications. However, quality viticulture is increasingly under pressure from climate change, which is altering the local conditions of many winegrowing areas. Therefore, maintaining traditional wine products will require the adoption of tailored adaptation strategies, including possible changes in the legal regulation of protected wines. To this end, it is necessary to have a comprehensive knowledge on PDOs including their extension, products and allowed practices. While there have been efforts to build databases that summarize the characteristics for individual wine PDO areas and to quantify the related effects of climate change, much information is still included only in the official documentation of the EU geographical indication register and has never been collected in a comprehensive manner. With this study we aim at filling this gap by building a spatial inventory of European wine PDOs that supports decision making in viticulture in the context of climate change. To map and characterize European wine PDOs, we analysed their legal documents and extracted relevant information useful for climate change adaptation. The output consists of a comprehensive geographical dataset that identifies the boundaries of all 1200 European wine PDOs at unprecedented spatial resolution and includes a set of legally binding regulations, such as authorized vine varieties, maximum yields and planting density. The inventory will allow researchers to analyse the impacts of climate change on European wine PDOs and support decision makers in developing tailored adaptation strategies. This includes, among others, the evaluation of new vineyard site selection, the expansion of cultivated varieties or the authorization of irrigation in vineyards.

Italy sweet revolution: how club grapes are transforming the table grape market

Italy is the leader table grape producer country in Europe and the eighth worldwide (OIV, 2021). The italian production area is sized at approximately 47,248 hectares with a production of 9.66 million quintals of grapes. Apulia and sicily are the main producing italian regions which collectively account for over the 90% of the italian production area (istat, 2022).

Prediction of aromatic attributes of red wines from its colour properties 

Wine perception is a multisensory experience that makes use of the sight, smell, and taste senses. When wine is sensorially assessed, the stimulus received generates multiple signals that tasters convert into organoleptic descriptors. Colour is commonly the first attribute evaluated during wine tasting. Moreover, the colour properties provide the taster with a priori information of the wine’s aroma. This preconceived perception is later confirmed or denied during the aroma evaluation.

The socioclimatic dynamics and the table grape production during a long-drought: the case of Brazilian semiarid

In 2022, the area cultivated with grapes in Brazil counted 75 thousand ha. About 1/2 of the grape production is located in rio grande do sul state, in South Brazil. Nonetheless, the northeast region, especially the Sao Francisco River Valley (SFRV), is increasing its area and production, mainly pushed by table grapes. The states of bahia and pernambuco already respond for circa 1/3 of brazilian grape production.