Proceedings Volume 2010 (format .pdf) - SimpBTH

important changes in the chemical composition of the wine (the diminution of thetotal acid, increases of pH because the dicarboxilic acid is replaced by themonobarboxilic acid); the taste and the aroma of the wine (the malic acid, moreaggressive for the gustative papilla, is replaced by one acid that stamps supplenessto the wine; the diminution of vegetal aroma, grassy and the appearance of newtastes, more agreeable); the biologically stability of the wine(the malic acidunstable biologically, is replaced by the lactic acid, biologically stable).148Table 3 Influence of the indigenous yeasts and selected alcoholic fermentation in redwinemakingYeasts Prefermementative Duration of fermentation, Alcohol, Residual sugar,phase duration,hoursdays% vol g/lGlycerol,g/lA 24 9 13,0 2,8 11,7B 18 8 13,1 1,8 11,9C 30 9 12,9 3,8 11,5Indigenuous 36 11 12,8 5,4 11,3Indigenous active 18 9 12,9 3,7 11,2Concerning the malolactic fermentation, the researches were effectuatedbetween 2004–2007, in the main vineyards of Oltenia hilly areas, situated in South-West of Romania: Sâmbureşti, Drăgăşani şi Dealurile Craiovei. Foe this study weused 4 varieties of grapes for high quality red wines: 2 varieties very knowable ininternational plane Cabernet-Sauvignon and Merlot, and also 2 autochthonousvarieties Fetească neagră and Novac. The period of researches include the differentyears like climatic conditions. So, year 2005 was for Romanian viticulture theworst in the last 50 years, very rainy and cold. Those conditions influenced thegrapes and wines production, quantitative and also qualitative. The years 2004 and2006 was a good vine-growing years, the climatic conditions was favorable forviticulture. The year 2007 was excellent for vine-growing by point of view ofclimatic conditions during the vegetation period and also during the ripening andover ripening.During the years have existed visible differences upon the length of time ofthe malolactic fermentation among the fermentated variant with lactic bacteriaresulted from the indigene microflora of the grapes and the fermentated variantwith selected lactic bacteria, but the differences where variable, depending on thechemical composition of the wine, as a result of the climate conditions of theviticultural year. In the good viticultural years (2004 and 2006), the length of timeof the spontaneous malolactic fermentation was between 45 and 60 days while thevariants with selected lactic bacteria, the duration was, on an average, 10 daysshorter, between 35 and 50 days. In drought-stricken years and very warm (2007),the length of time of the malolactic fermentation was between 35 and 45 days in