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The influence of berry size on wine quality is a matter of debate. With the aim to contribute to that debate, a study of the influence of the varieties Tannat

The anthocyanin composition of Tannat red wines obtained with four winemaking techniques was evaluated in different years. The wines were elaborated with traditional maceration (TM), cold pre-fermentative maceration, delayed extraction of anthocyanins and extended maceration. Two vinifications were carried out for each technique, employing 70 kg of grapes in each one. The anthocyanin composition of wines was analysed by high-performance liquid chromatography-diode array detection. The results confirm the fundamental role of the grape composition on the anthocyanin composition of the wines. The winemaking had an important effect on the total concentration of anthocyanins and also may modify the anthocyanic profile of wines. The wines obtained with TM had higher or similar content of anthocyanins than those elaborated with the other techniques. Canonical discriminant analysis of data showed that vintage has a greater effect on anthocyanin concentration than winemaking techniques.

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The phenolic potential of the grapes of Tannat, Cabernet Sauvignon and Merlot produced in the south region of Uruguay was analysed in four years. The grapes of Tannat had the highest total phenolic richness (A280 = 80.0), total anthocyanin potential (ApH1 = 2540 mg L )1 ) and extractable anthocyanin potential (ApH3.2 = 1269 mg L )1 ), although there were important differences between the years. Representative winemaking of each vineyard was carried out. The differences verified in the grapes phenolic indexes were related to the colour and polyphenolic composition of the wines. The correlations between the phenolic indexes of the grapes and the colour and polyphenolic composition of the wines were very high. The estimation of the polyphenolic richness and the extractability of the anthocyanins of the grapes allow to improve the management of the winemaking and the prediction of the chromatic characteristics and the global polyphenolic composition of the wines.

Cold Pre-fermentative Maceration (CPM) is an interesting winemaking technique to enhance the extraction of pigments, aroma and flavour compounds from grape skins to wine. This work aimed to evaluate the effect of Cold Prefermentative Maceration (CPM) on the composition of Tannat red wines produced in Uruguay in several vintages. For this purpose, wines elaborated by CPM were compared with control wines produced by Traditional Maceration (TM) in 4 years. Control wines (TM) were made with classical fermentation on skins. The CPM was carried out with additions of dry ice for 5 days to keep the must at 10ºC. Wines were analysed at devatting. The impact of CPM on composition and color of wines was different in each year. Color intensity was significantly higher in CPM than control wines in 2007 and 2009 whereas the anthocyanins levels were higher in control wines every year. However, CPM wines had the highest polyphenols contents in

Phenolic composition of Tannat variety grapes grown in South of Uruguay and harvested during two consecutive years (1999 and 2000) was determined. The effect of the cluster thinning in setting and veraison, etephon applications, and pruning at 4 and 6 buds per rod on the phenolic composition of the grapes and their respective red wines was compared. During the harvest, which took place in the technological maturity, the phenolic maturity indices of grapes were estimated. Wines were analysed a month after the alcoholic fermentation, determining its colour and phenolic content. The different treatments had a different incidence on the total phenolic content, the total and extractable anthocyanins of the grapes, depending also on the year of harvest. There was no correspondence between the technological and phenolic maturity indices, which varied depending on the treatments and the years of harvest. The anthocyanic contents of the grapes and wines did not correlate significantly due to the diverse incidence of the environmental conditions and the harvest practices, the conditions of the maceration and the evolution of the polyphenols during the vinification.

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