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This diploma thesis deals with the analysis of the influence of different methods of primary fermentation of the vine musts on the analytical and sensoric parameters of the wines produced. For this goal different wine samples were produced using active dry wine yeast fermentation, spontaneous fermentation and fermentation with prepared ferment that contained original cultured yeast from local wine yard. The wines were produced from three vine varieties from year 2012 and 2013. The analytical and sensoric evaluation was subsequently carried out. The result of the experiment show a good and even sensoric quality of the wines produced using the active dry wine yeast fermentation, yet certain uniformity is apparent. On the contrary the spontaneous fermentation shows traces of unevenness in the sensoric quality evaluation. The most important finding is that the method that produces wine using the prepared ferment is a full alternative to the methods of spontaneous or active dry wine yeast fermentation and that in many cases leads to even better sensoric evaluation than these two methods. The prepared ferment method has a great potential in wine making practice mainly for high quality wines that focus on the varietal character, originality, story of origin, local tradition and "terroir".

The aim of this master thesis was to compare the effect of active dry wine yeast (ADWY), own yeast starter and spontaneous fermentation on the quality of wine produced, knowing that the fermentation is a key process in winemaking. An experiment was run with the grape varieties Veltlínske zelené and Pálava, vintage 2016, grown at University vineyards in Lednice. Racked and moderately sulfited must with optimal yeast assimilable nitrogen and sugar content was the starting point of the experiment. It was inoculated by commercial ADWY, a yeast starter prepared previously from the grapes of the same origin and the last sample was not inoculated so fermented spontaneously. Fermentation took place in the University wine cellar. Final wines were not treated by any preparate except sulfiting. Sensory and analytical analysis took place in spring 2017. The usage of self-prepared yeast starter has shown the highest sensory quality in both varieties. It has been confirmed that this old and reliable method is capable of producing high quality wines reflecting the terroir.

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