Abstract: It is widely known, that influence of temperature on winemaking is significant. Fermentation at higher temperatures causes losses of aromatic substances up to 75% (when fermentation is carried out at 30 °C). Hence, temperature of the fermentation must be controlled during entire fermentation. Therefore, first part deals closer with the material and energetic balance within the fermenter during fermentation, what is the most crucial part of winemaking. We assumed typical concentrations of nitrogen and sugar, adapted a model and simulated fermentation process. Our attention deals with duration of the fermentation, cooling requirements and in the case of refrigeration failure we investigated temperature increase and minimal cooling requirements to cool it back in a proper time. Second part deals with simple material and energetic balance at all. The measurement was made in industrial scale in one Slovak wine factory.