Alberto Miele

Avaliação da uva cv. Isabel para a elaboração de vinho tinto

Isabella grape, originated from the South of the United States, is one of the most important varieties of Vitis labrusca. Today it is the most diffused variety in the Serra Gaucha, the southern viticultural region of Brazil, where it represents near 45% of the total production. Isabella grape is used to make red table wine and juice and it is commercialized as table grape too. Due to its importance, this work was carried out from 1988 to 1994 to study grape maturation, cluster characteristic, must composition and chemical and sensory attributes of its red table wine. The results showed that Isabella grapes had small and loose clusters, with large berries and seeds. The must showed a light pink color, good level of sugar, low malic acid and low titratable acidity. The wine has an attractive red color; the aroma is intense and shows a good varietal characteristic; finally, sensory analysis shows the wine needs a better balance and softness.

Avaliação da cv. Merlot para elaboração de vinho tinto

Merlot is a traditional grape of the Saint Emillion wines, Bordeaux region - France. It was introduced into, the State of Rio Grande do Sul by the Estacao Agronomica de Porto Alegre, Brazil. Today, of the red grape cultivars it shows the largest production in the Serra Gaucha region. The purpose of this work was to evaluate the enological potential of Merlot grapes for red winemaking. To achieve this purpose, variables related to berry clusters, must and wine were measured between 1987 and 1994 vintages, from Merlot vineyards located in the municipality of Bento Goncalves. The results showed that Merlot grapes have clusters of medium size (161.9g) and small berries (1.61g). The must showed adequate sugar level (18.4oBrix), high titratable acidity (104mqL-1) and medium pH 3.21. The wine Merlot had an alcohol content of 10.8% v/v, titratable acidity of 70.3meqL-1 and pH 3.49. With regard the sensory evaluation, Merlot wine showed a good red color intensity with violet reflexes. The mouth feel soft and balanced.

Analytical characteristics and discrimination of Brazilian commercial grape juice, nectar, and beverage

A producao e a comercializacao de suco de uva brasileiro estao aumentando anualmente devido a sua tipicidade, qualidade e valor nutritivo. Por isso, realizou-se este trabalho em face de sua importância para a agroindustria de vinho e de suco. O objetivo deste trabalho foi determinar a composicao e discriminacao do suco de uva em relacao a outras bebidas dele derivadas. Avaliaram-se 24 amostras de sucos de uva −integral, adocado e reprocessado −, nectar de uva e bebida de uva. As variaveis classicas foram determinadas por meio de metodos fisico-quimicos; os acidos tartarico e malico, por HPLC; o metanol, por cromatografia gasosa; e os minerais, por espectrofotometria de absorcao atomica. Esses produtos foram discriminados pela Analise de Componentes Principais (ACP). Os resultados mostram que os sucos de uva integral e adocado discriminaram-se dos demais porque tiveram valores mais elevados de solidos soluveis totais, acidos tartarico e malico, a maior parte dos minerais, compostos fenolicos e relacao K/Na, enquanto que o nectar de uva e a bebida de uva apresentaram valores mais elevados da relacao oBrix/acidez titulavel. O suco de uva reprocessado descriminou-se dos demais devido a elevada concentracao de Li e Na e baixo matiz.

AVALIAÇÃO DA CV. CABERNET FRANC PARA ELABORAÇÃO DE VINHO TINTO

Cabernet Franc grape is originated from Bordeaux, France. It was introduced in the Serra Gaucha region in the south of Brazil, by the Estacao Agronomica the Porto Alegre, RS. It is used to elaborate young red wine, but it can be aged too. Due to the importance of Cabernet Franc, this work had the objective to determine its agronomic and winemaking characteristics. To achieve this purpose, variables related to the berries, clusters, must, and wine were performed from 1987 to 1994. The results showed that Cabernet Franc grapes have clusters of medium size and small berries. The must has adequate sugar and titratable acidity levels for vinification. The Cabernet Franc wine has a high concentration of K and higher alcohols. The sensory evaluation showed that it has a ruby color with violet reflexes when young and presents color intensity varying with the vintage. The aroma is characterized by red fruits and pimiento. In the mouth it has good structure and equilibrium and a nice personality.

Efeito da safra vitícola na composição da uva, do mosto e do vinho Isabel da Serra Gaúcha, Brasil

Variation of the climatic conditions among years is one of the most important factors having influence on wine composition and quality. This work evaluated the effect of the 1999, 2000, and 2001 vintages of the Isabel grape, must, and wine composition from Serra Gaucha, Brazil. In this way, twenty-two grape growers from 11 communities of this region were taken. From each grower, 60kg of ripened grapes were sampled from which evaluations on grape and must were performed and microvinifications were made. Results showed that the vintage had a significant effect on cluster and berry weight, but there was no effect on stem/cluster weight ratio. In the same way, there was differences on the majority of the variables of the must of Isabel studied, exception to the °Brix/total acidity ratio. It also had effect on the majority of the variables of the wine, exception to the K, Mn, Cu, and Rb cations. In general, the 1999 vintage was better, because it showed more adequate parameters for total acidity, dry extract, reduced dry extract, alkalinity of ashes, tannins, anthocyanins, and glycerol, variables that determine wine structure and color, important factors for wine quality.

Evolução da maturação da uva cabernet franc conduzida no sistema lira aberta

Objetivou-se com este trabalho avaliar a evolucao da maturacao da uva ‘Cabernet Franc’ conduzida no sistema lira aberta. O trabalho foi realizado durante o ciclo vegetativo de 1995/96, em oito vinhedos instalados em diferentes regioes viticolas dos municipios de Bento Goncalves e Monte Belo do Sul, RS. As amostras, formadas por 200 bagas, foram coletadas semanalmente a partir do inicio da maturacao e esmagadas para a extracao do mosto. Determinaram-se as variaveis teor de solidos soluveis totais (TSS), densidade, pH, acidez total, acido tartarico e acido malico. Pelos resultados, verificou-se que houve aumentos lineares significativos do teor de solidos soluveis totais, da densidade, do pH e das relacoes TSS/acidez total e acido tartarico/acido malico; entretanto, houve diminuicao linear e significativa da acidez total, do acido tartarico e do acido malico.

Composição físico-química do vinho Cabernet Franc proveniente de videiras conduzidas no sistema lira aberta

-1 . Os resultados dos vinhos avaliados foram relativamente similares aos encontrados em vinhos Cabernet Franc da mesma regiao elaborados com uvas provenientes de videiras conduzidas em latada. Eles evidenciam que o sistema de conducao da videira em lira aberta constitui-se como alternativa para a producao de vinho tinto fino na Serra Gaucha. Palavras-chave: enologia, composicao quimica, vinho, Cabernet Franc, sistema de conducao. SUMMARY PHYSICO-CHEMICAL COMPOSITION OF CABERNET FRANC WINE FROM VINEYARDS CONDUCTED IN THE LYRE SYSTEM. The objective of the work was to evaluate the physico-chemical characteristics of the Cabernet Franc wine from the 1995/1996 vegetative cycle. It was conducted in eight vineyards in the communes of Bento Goncalves and Monte Belo do Sul, State of Rio Grande do Sul, Brazil. From each vineyard, two microvinifications were elaborated and wines were analysed by physicochemical, atomic absorption spetrophotometry, and liquid and gas chromatography processes. The parameters of the most significant variables were the following: alcohol 9.65%, total titratable acidity 69 meq L-1, pH 3.46, reduced dry extract 16.0 g L-1, K in the ashes 49.4%, tartaric acid 33 meq L -1 , glycerol 9,3 g L -1 , proline 669 mg L -1 , anthocyanins 330 mg L -1 , tannins 1.19 g L -1 , color intensity 0.286, K 1,078 mg L-1, methanol 101.7 mg L-1, and summ of higher alcohols 450 mg L-1. The results found in the analysed wines showed similar results to parameters previously determined in Cabernet Franc wine from the same region elaborated from grapes cultivated in the pergola system. This makes evident that grapevines conducted in the lyre system are an alternative to produce quality red wine in the Serra Gaucha region.

Acidez na vinificação em tinto das uvas Isabel, Cabernet Sauvignon e Cabernet Franc

The acidity is an important sensory characteristic of the wine, and influences stability and collor. The insolubility of tartaric acid in the vinification by salt forms can change the titratable acidity and the pH of wines. This work evaluated the acidity evolution during the vinification of Isabella, Cabernet Sauvignon, and Cabernet Franc varieties in the Serra Gaucha region. The wines were elaborated by the microvinification process in the 1995 vintage. The evolution of titratable acidity, pH, tartaric acid, and potassium were analyzed in five phases of winemaking: immediately after crushing, after cap removal, and after alcoholic fermentation, malolactic fermentation and tartrate stabilization. Results showed a different evolution of acidity parameters in the Isabella, as compared to Cabernet Sauvignon and Cabernet Franc varieties. The Isabella wine showed higher levels of titratable acidity and tartaric acid, and lower pH and potassium than Cabernet Sauvignon and Cabernet Franc wines.

Efeito de três processos de vinificação sobre a composição química e a qualidade do vinho Cabernet Franc

The effects of three processes of vinification on chemical composition and quality of Cabernet Franc wine were evaluated from the 1987 to the 1990 vintages. The vinifications were made in an industrial scale by the following processes: conventional vinification, thermovinification and carbonic maceration. The analyses performed were alcohol, total acidity, reducing sugar, ash, dry extract, phenolic and volatile compounds and mineral elements. The quality was evaluated by sensory analysis. Data were submitted to principal component analysis (PCA) and to analysis of variance, where the three first axes explained 68.2% of the total variation. The PCA permitted to separate the wines of carbonic maceration from the other two vinification processes. The variables presenting important variation effect were the higher alcohols, cations and phenolic compounds. The sensory evaluation showed that carbonic maceration originated lighter wines with lower color intensity; the thermovinification and the conventional vinification originated wines with better body, better quality and gustative balance and with higher varietal characteristic.

Teores de cátions dos vinhos da Serra Gaúcha

Cations represent an important part of the ash content and they can contribute to characterize wines from different viticultural regions. The purpose of this work was to determine the concentration of the main cations in the wines of the Serra Gaucha region in Brazil. Six hundred table wines, primarily from American/hybrid varieties, and 380 wines elaborated with Vitis vinifera varieties, both including red, rose and white wines, were analyzed. The analyses of K+, Na+, Li+ and Rb+ were performed by flame emission, while Ca++, Mg++, Mn++, Fe++, Cu++ and Zn++ analyses were performed by atomic absorption. Data were submitted to analysis of variance and the Tukey test and to Principal Component Analysis (PCA). Results showed that there was no significant difference in the concentration of Na+, Cu++ and Zn++ cations among the different kinds of wine from the Serra Gaucha viticultural region; red table wine had a higher Mn++ concentration than the vinifera wines; table and vinifera roses presented higher Fe++ concentration; and vinifera had higher K+ and Rb+ values. PCA permitted the differentiation of wines by their color - red, rose and white - and by their kind - vinifera and table wine.