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Investigation of yeast properties during the beer fermentation
Kociánová, Lenka ; Vítová, Eva (referee) ; Omelková, Jiřina (advisor)
In this diploma thesis, the properities of brewery’s yeasts during the operation beer fermentation in the selected brewery and dependences of diferent agents and their influence on viability and vitality of the yeasts were studied. Other observed properities were physiological state, pH, temperature, a value of soft and coarse sludges, a value of dissolved oxygen in wort, the level of wort’s fermentation. It were collected the samples of fermenting wort and washing yeasts for determination. The used yeasts were observed from the first time until thein last used (generally 4 times). pH, temperature, apparent fermenting and total numer of yeast cells were measured in the collected samples. The used yeasts were washed before every other application and vitality was determined. The number of death cells were observed by this method. The number of death cells never fell bellow 5 %. The value of dissolved oxygen in wort is also the important agent for the growth of yeasts. The touchs with low number of oxygen showed that the time for fermentation had to be longer (by about 3 or 4 days more). The touchs with higher number of sludges showed that the sludges haven’t any influence on the yeasts and the procces of fermentation. Confirm the accuracy of the repeated used of the yeasts was the object of this thesis.
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Sledování fermentability sladin u vybraných druhů sladů
Zárubová, Emílie
In my diploma thesis on the topic “Monitoring the fermentability of worts for selected types of malt” has been processed information on the fermentabilitity of worts, the degree of fermentation, extractive substances and the factors that affect them. Furthermore, the thesis processes themes, which deals with malt, its production, requirements for malt and especially types of malt. Information is included not only conventional barley malt, but also on some less common types of malt. The first half of the diploma thesis processed this information on a theoretical level. The second half of the diploma thesis is focused on experimental activites related to the production of malts, worts and subsequent fermentation of the worts. For the production of the worts were used barley, wheat, oat, rye, corn and millet malt. The amount of extractives before fermentation, after fermentation and the amount of alcohol were determined for individual worts. Based on the difference between the extract before fermentation and after fermentation, the fermentability of worts produced from individual types of malts was determined. The results obtained are compared with those already known and with those obtained with conventional barley malt. According to the results, wort made from wheat malt shows the best fermentability. Wort made from barley malt shows the second best fermentability. Furthermore follow rye wort, oat wort, wort made from millet malt and the wort from corn malt shows the worst fermentability.
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Možnosti modifikace receptur pro výrobu nealkoholického piva
Kovář, Pavel
In this work, I focused on linking the benefits of using special yeasts with limited alcohol production and improving the sensory profile using selected malts. Three worts were prepared from different basic malt, Pilsen, Vienna and Munich. The worts were always fermented with two strains of yeast Saccharomycodes ludwigii, DSM 70550 and DSM 70551. Each beer was analyzed on a FermentoFlash instrument, where the alcohol content was determined. Furthermore, the pH of each beer was measured. Subsequently, a real achievable degree of beer fermentation was determined using a conventional bottom-fermenting brewery yeast strain and, at the same time, the alcohol content was determined after the complete fermentation of the beer by a conventional bottom-fermenting brewery yeast strain. All fermented beers of Saccharomycodes ludwigii were also subjected to sensory analysis. Finally, all obtained data were statistically evaluated.
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Investigation of yeast properties during the beer fermentation
Kociánová, Lenka ; Vítová, Eva (referee) ; Omelková, Jiřina (advisor)
In this diploma thesis, the properities of brewery’s yeasts during the operation beer fermentation in the selected brewery and dependences of diferent agents and their influence on viability and vitality of the yeasts were studied. Other observed properities were physiological state, pH, temperature, a value of soft and coarse sludges, a value of dissolved oxygen in wort, the level of wort’s fermentation. It were collected the samples of fermenting wort and washing yeasts for determination. The used yeasts were observed from the first time until thein last used (generally 4 times). pH, temperature, apparent fermenting and total numer of yeast cells were measured in the collected samples. The used yeasts were washed before every other application and vitality was determined. The number of death cells were observed by this method. The number of death cells never fell bellow 5 %. The value of dissolved oxygen in wort is also the important agent for the growth of yeasts. The touchs with low number of oxygen showed that the time for fermentation had to be longer (by about 3 or 4 days more). The touchs with higher number of sludges showed that the sludges haven’t any influence on the yeasts and the procces of fermentation. Confirm the accuracy of the repeated used of the yeasts was the object of this thesis.
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