L'effet du climat viticole sur la typicité des vins rouges: caractérisation au niveau des régions viticoles Ibéro-Americaines.

RÉSUMÉ Il n?existe presque pas d?études qui caractérisent l?effet du climat viticole sur la typicité des vins en considérant les différents types de climats à l?échelle mondiale. Cette étude fait partie d?un projet CYTED de zonage vitivinicole. L?objectif a été de caractériser l?effet du climat viticole sur la typicité des vins sur une macro région viticole du monde. La méthodologie a été appliquée à un ensemble de 45 régions viticoles situées sur 6 pays Ibéro-Américains : Argentine, Bolivie, Brésil, Chili, Espagne et Portugal. Le climat viticole de chaque région viticole a été caractérisé para les 3 indices climatiques viticoles du Système CCM Géoviticole : IH (Indice Héliothermique de Huglin), (IF) Indice de Fraîcheur des Nuits) et IS (Indice de Sécheresse). Les principales caractéristiques sensorielles observées de façon fréquente sur des vins rouges représentatifs élaborés avec des raisins-de-cuve de chacune des ces 45 régions viticoles ont été décrites pour des ?nologues de chaque pays, an utilisant la méthodologie proposée par Zanus & Tonietto (2007). L?évaluation sensorielle réalisée concerne l?intensité de perception de la Couleur (Cou), de l?Arôme Total (Ar), de l?Arôme ? fruit mûr (Ar-Fm), de la Concentration (Con), de l?Alcool (Al), des Tanins (Tan), de l?Acidité (Ac) et la Longueur en bouche (Lon). Les données ont été soumises à l?analyse des corrélations pour l?ensemble des variables et à l?ACP. L?étude indique qu?une partie de la typicité des vins es déterminée par le climat viticole des régions et que les indices du Système CCM Géoviticole sont pertinents pour relier aux caractéristiques sensorielles des vins. Le déterminisme de l?IH, de l?IS et de l?IF à été mis en évidence. MOTS CLÉS : climat viticole, indice climatique, Système CCM, vin, typicité.

Régime thermique en période de maturation du raisin dans le géoclimat viticole.

Mots clés :indice de fraîcheur des nuits, amplitude thermique, Système CCM Géoviticole, zonage, qualité. Key words: cool night index, thermal amplitude, MCC System for World Viticulture, zoning, quality. RESUME Le régime thermique en période de maturation du raisin est l?une des variables déterminantes de la coloration du raisin et de la richesse en arômes, anthocyanes et polyphénols des vins. L?objectif du travail est de caractériser le régime thermique, notamment la fraîcheur des nuits et l?amplitude thermique au cours de la maturation, au niveau du climat viticole mondial, sur une base des données de 100 régions viticoles dans 30 pays, obtenue par l?intermédiaire de l?Organisation Mondiale de la Météorologie - OMM. Plusieurs indices climatiques viticoles ont été calculés: l?Indice de Fraîcheur des Nuits ?IF (ºC), l?Indice Héliothermique de Huglin ?IH (ºC) et l?Indice de Sécheresse ?IS (mm) du Système de Classification Climatique Multicritères Géoviticole, et l?amplitude thermique moyenne en août et septembre Aa-s (ºC). Egalement, sur la période véraison-récolte ?v-r(moyenne des 30 jours précédant la date de récolte, estimée sur la base d?un Indice Héliothermique de HUGLIN égal à 1.900 - approximatif pour la maturation du Cabernet-Sauvignon): la fraîcheur des nuits (FNv -r), la température moyenne de l?air (Tv-r), la température maximale de l?air (Txv-r) et l?amplitude thermique (Av-r). Les résultats montrent que IH est corrélé avec Tv-r (r=0,79**) et avec Txv-r (r=0,80**). IH représente donc bien les conditions thermiques générales de la période de maturation en ce qui concerne la température moyenne et maximale de l?air. Mais IH n?est pas corrélé ni avec Aa-s ni avec Av-r. Par contre, IF est corrélé avec Aa-s (r=-0,70**) et FNv-r est corrélé avec Av-r (r=-0,69**). Cette corrélation doit justifier, en partie, l?usage assez courant de l?amplitude thermique comme indicateur de bonnes conditions thermiques de maturation pour les régions qui présentent des valeurs élevées. Mais ce raisonnement peut amener à des caractérisations erronées. Le travail met en évidence, également, ?importance de considérer le bilan hydrique des régions (IS) dans l?analyse du régime thermique sur la qualité du raisin. On peut onclure que pour avoir une bonne caractérisation du régime thermique en période de maturation il faut considérer la fraîcheur des nuits (IF étant un bon indicateur de FNv-r moyen des régions, avec un r=0,80**), caractérisation qui peut être améliorée avec l?information des températures maximales et de sur 11l?amplitude thermique en période de maturation du raisin. Les éléments présentés peuvent servir à améliorer les indices climatiques pour estimer le potentiel qualitatif du raisin des différentes régions viticoles, notamment en complément de IF. ABSTRACT The thermal conditions during the grape ripening period are important variables related to colour of the grapes, anthocyanins, polyphenols and flavour of the wine. The main purpose of this work was to characterise the thermal conditions, especially the night coolness and the thermal amplitude during maturation, in the geoclimate of the world vine culture. A database of 100 grape-growing regions of 30 countries obtained from the World Meteorology Organisation (WMO) was used. Some climatic indexes were calculated: Cool Night Index ?IF (°C), Huglin?s Heliothermal Index ?IH (°C) and Dryness Index ?IS (mm), from the Multicriteria Climatic Classification System for World Viticulture, and the thermal amplitude in August and September Aa-s (°C). Over véraison-harvest period ?v-r(mean of the 30 days before harvesting date, estimated on the basis of HUGLIN Heliothermal Index equal to 1,900 ? approximately value to ripen Cabernet-Sauvignon) similar indexes were obtained: the cool night (FNv-r), the mean air temperature (Tv-r), the maximal air temperature (Txv-r) and the thermal amplitude (Av-r). The results showed that IH is positively correlated with Tv-r (r=0.79**), Txv-r (r=0.80)and IF (r=0.67**). Therefore, IH represents well the general thermal conditions during maturation period, specially concerning the mean and the maximal air temperature. owever, IH was correlated neither with Aa-s nor to Av-r. IF was negatively correlated with Aa-s (r= -0.70**) and FNv-r was negatively correlated with Av-r (r=-0.69**). The correlation to some extent explains the current use of the thermal amplitude to predict good ripening thermal conditions for those regions that show high values. As here we have described, this thinking may give incorrect results. This work has also showed the importance to consider the water balance of the regions (IS) in the effect of the thermal conditions in grape quality. We conclude that the characterisation of the thermal conditions during the ripening period do need the cool night index (in this case, IFis a good index to provide the mean FNv-r of the regions, r=0,80**). Factors other than cool night which influence this characterisation are both maximal air temperature and thermal amplitude data. The elements presented in this work, in addition to IF , may improve the climatic indexes to be used to predict the qualitative potential of grapes from different regions.

Aromatic stability of Syrah and Petit Verdot tropical wines from Brazil.

The production of fine wines in the Sub-middle of the São Francisco River Valley, Northeast of Brazil, is relatively recent, about twenty-five years ago. This region presents different characteristics, with a tropical semiarid climate, in a flat landscape. Presenting high annual average temperature, solar radiation and water in abundance for irrigation, it?s possible the scaling the grape harvests for winemaking throughout the year, allowing to obtain until two harvests per year. Several factors may affect the aromatic compounds in wines, such as viticulture practices, climatic conditions, cultivars and winemaking process. This study aimed to evaluate the aromatic stability of Syrah and Petit Verdot tropical wines elaborated in two different periods in the year. The grapes were harvested in the first and second semesters of 2009, in June and November. The wines were elaborated and then, they were bottled and analyzed in triplicate, thirty days and one year after bottling, by gas chromatography with ionization detector flame (GC-FID), to evaluate the profile and the stability of the aroma compounds. Principal component analysis was applied to discriminate between wine samples and to find the compounds responsible by the variability. The results showed that Syrah and Petit Verdot tropical wines presented different responses, for stability of higher alcohols, esters and carboxylic acids.

Influence of the vintage, clone and rootstock on the chemical characteristics of Syrah tropical wines from Brazil.

In the Northeast of Brazil, vines can produce twice a year, because annual average temperature is 26ºC, with high solar radiation and water availability for irrigation. Many cultivars have been tested according to their adaptation to the climate and soil, and the main variety used for red wines is Syrah. This work aimed to evaluate five clones of Syrah, grafted on two rootstocks, in two harvests of the second semester of 2009 and 2010, according to the chemical analyses of the wines.The clones evaluated were 100, 174, 300, 470 and 525, the rootstocks were Paulsen 1103 and IAC 313 (Golia x Vitis caribeae). Grapes were harvested in November 2009 and 2010 and the yield was evaluated. Climate characteristics of each harvest was determined and correlated to the results. Wines were elaborated in glass tanks of 20 L, with alcoholic fermentation at 25ºC for seven days, then wines were pressed and malolactic fermentation was carried out at 18ºC for 20 days. The following parameters were analyzed: alcohol content, dry extract, total anthocyanins, total phenolic index. High performance liquid chromatography was used to determine tartaric, malic, lactic and citric organic acids. Results showed that wines presented different concentrations of classical analyses, phenolics and organic acids according to the harvest date, rootstocks and clones. Principal component analysis was applied on data and clusters with wine samples were formed, explaining the variability, and results are discussed.

A concept for the viticulture of 'tropical wines'.

At worldwide level, the classical viticulture produces wines is almost all places in different climate types, where it is possible to obtain only one harvest per year. In these conditions, bud burst in vines occurs as a result of temperature raising at the end of the winter?beginning of spring. With the development of the vegetative cycle, grapes arrive to maturity/harvest period at the end of the summer?beginning of the fall season. After the fall of the leaves, vines undergo a dormant period with a vegetative repose (condition found also in some intertropical producer regions). A lot of grapes are produced for a long-time in the intertropical zone, but only a little part is used to winemaking. Considered a challenge in the past, to produce quality wines in the tropics became reality. The present industry of fine wines began about 30 years ago. Today, there are many commercial wineries in several countries in Occident and Orient in the tropical zone of the globe, like in Brazil, India, Thailand and Venezuela, producing some million liters of fine wines per year - called ?tropical wines?. This article analysis these climates, in relation to the particular viticulture adapted and developed, where it is possible to have more than one cycle per year, with one or more harvests per year. Based on the particularities of this viticulture, a characterization is proposed for the viticulture of ?tropical wines?. Some examples showing different tropical climates are presented.

Climatic groups in Ibero-America viticulture compared to worldwide wine producer regions.

The wine production is an important activity in many Ibero-American countries. The wine producer regions of these countries configure a large use of different climate types and viticultural climates. In a vitivinicultural zoning project of CYTED (Ibero-American Program for Science, Technology and Development), a viticultural climatic characterization was done in this macro viticultural region. The project have assembled a climatic database that characterizes the viticultural regions, including relevant variables for viticulture: air temperature (mean, maximum, and minimum), precipitation, relative humidity, solar radiation, number of sunshine hours, wind speed, and evapotranspiration. Using indices of the Geoviticulture MCC System (HI, CI and DI), more than 70 viticultural regions in different countries (Argentina, Bolivia, Brazil, Chile, Cuba, Spain, Mexico, Peru, Portugal and Uruguay) were characterized according to its viticultural climatic. The results, which will be integrated to the worldwide database of the MCC System, showed that the Ibero-American viticulture is placed in a wide range of climatic groups of the wine producing regions around the world. This article presents the climatic groups found in Ibero-America, identifying also some new climatic groups not yet found in other regions of the world. This work also identifies some climatic groups not found in Ibero-America viticulture. The research has also highlighted viticultural areas characterized by climates with ?intra-annual climatic variability?, with the potential to produce more than one growing cycle per year. The results allow to conclude that the wide variability and climatic diversity present in Ibero-America may be one of the reasons to explain the diversity in terms of wine types, sensorial characteristics, typicity and uniqueness of wines produced on this macro-region.

I vini passiti: alcune tecniche di vinificazione a confronto

La pratica dell’appassimento fa parte della cultura mediterranea sin dall’era del Neolitico. Tale tecnica veniva praticata anche nell’Antica Grecia e successivamente nelle diverse regioni dell’Impero Romano. Il presente elaborato si propone, attraverso lo studio dello stato dell’arte relativamente ai vini passiti, di illustrare alcune tecniche di vinificazione, approfondire le caratteristiche salienti di questa tipologia di vino e delinearne il posizionamento sul mercato. In particolare, si sono prese in considerazione le tre tecniche di appassimento comunemente utilizzate: appassimento in campo, in fruttaio e in cella. Per quanto concerne l’appassimento in campo, si è fatto un approfondimento in merito agli effetti indotti dalla Botrytis cinerea, muffa nobile la cui presenza sulle uve permette di dar vita a vini botritizzati dalle caratteristiche distintive, come nel caso dell’Albana Passito di Romagna. I metodi di appassimento che prevedono l’utilizzo di un locale apposito (fruttaio e cella) si differenziano per il controllo della temperatura e dell’umidità e quindi il processo di disidratazione dell’acino avviene in tempi più rapidi e con minor rischio di sviluppo di patogeni. Lo sviluppo di queste tecniche come ha impattato sul consumo di vino passito? Negli ultimi anni il consumo di vino sta aumentando, e l’Italia è uno dei principali paesi produttori e consumatori. Il vino passito però, data la sua complessità e le particolari occasioni d’uso, occupa un piccolo spazio in questo scenario ed è caratterizzato da una concentrazione nel consumo delle produzioni locali, faticando a occupare un posto di rilievo sul mercato. Nonostante ciò, vi sono anche casi di successo, come quello dell’Amarone della Valpolicella DOCG, che lasciano ben sperare in uno sviluppo futuro.