Sedimentation and flotation are the most common processes for clarifying grape juice prior to alcoholic fermentation. The aim of this Master's thesis was to determine the effects of these two grape processing procedures on the quality of the wine produced. Short-macerated grape juice of the Blaufränkisch variety, which is suitable for the production of rose wine, was used for the fermentation experiments. The juice was produced in the Podravje wine-growing region in vintage 2019. Half of the grape juice was clarified by sedimentation and the other half by flotation, using argon as a foaming agent. For gravimetric monitoring of fermentation, we defined three classes for flotated grape juice and three for sedimented grape juice with a volume of 0.5 L. During fermentation, we monitored the mass of the bottles and used this to calculate the kinetics and rate of fermentation. After fermentation, the chemical parameters of the samples were determined using a WineScanTM instrument. For sensory analysis and gas chromatography, the flotated and sedimented juice was fermented in four 5-litre fermentation bottles to which yeast nutrients were added during fermentation. After fermentation, the wine was racked, the chemical parameters were analysed (WineScanTM), the concentrations of volatile components were determined (gas chromatography), the samples were sensory evaluated, and the microbiological composition of the yeast was checked. The results showed that sedimented and flotated wine samples had similar chemical compositions. Undesirable volatile compounds were formed in the sedimented samples, which had a negative effect on wine sensory quality. The wine produced from flotated grape juice was rated sensory better (1-point difference on the Buxbaum scale).
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