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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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Comparison of selected quality indicators of beers produced by different technologies
BUDÍN, Dominik
The bachelor thesis deals with the comparison of selected qualitative indicators beers produced by different technologies. The practical part is focused on the comparison of ten top-fermented beers from different industrial breweries, microbreweries and home breweries production. The individual beer samples were sensory assessed on the basis of subjective evaluation among ten evaluators. Respondents rated the following using a questionnaire bitterness, drinkability, aroma, flavour intensity and overall impression of the sample. At the answers of the respondents, graphs were drawn up and then evaluated and described verbally. In the research part of the bachelor thesis it was found by qualitative research, which top-fermented beers are preferred by men and conversely, which beers are preferred by women.
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Vliv kmene pivovarských kvasinek na finální kvalitu piva
Nevrtalová, Ivana
The diploma thesis is divided into two main parts. The first part is a compilation of available publications devoted to the beer production. This theoretical summary is focused mainly on the wort fermentation and discusses important and commonly used brewing yeast strains of the bottom and top fermentation. Moreover, the metabolism of yeast cells, resources essential to their life cycle and compounds that occur in the final product are described in the thesis.The second part of the thesis is a practical part containing data from the research focused on top-fermenting yeast strains available on the Czech market. The selected top-fermenting yeast strains were used for the wort fermentation created by the unified production technology. Obtained beer samples were subsequently analysed by laboratory techniques as well as by sensory analysis.In conclusion, this thesis compares the amount of the alcohol, true extract and original wort in individual beer samples. Additionally, the amount of residual sugars, and glycerol and ethanol levels in these samples were compared by HPLC analysis.
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Možnosti výroby svrchně kvašených piv a jejich vlastnosti
Zika, Zdeněk
Bachelor work deals the description of the raw materials needed for the production of beer, characteristic of all parts of the production process and description of the kinds of top-fermented beers. The work includes two experiments: laboratory and semi-operation. The laboratory experiment has been making beer from different colored varieties of wheat. Production of samples for this experiment was carried out under laboratory conditions. For beer produced were then examined sensory and qualitative differences. Semi-operation experiment is dedicated to the production of wheat beer in a microbrewery. In two wheat beers produced by different recipes again performed sensory and qualitative determination.
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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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Comparison of traditional beer production with modern technologies
FLOSOVÁ, Anna
Presented Bachelor thesis was focused on comparison of traditional beer production with modern technologies. From comprehensive theory of beer brewing technology was the main point of the work devoted to brewer´s yeast and beer fermentation process, which has made the greatest progress during the development of beer production technology. Chapter about brewer´s yeast is dealing with their taxonomy, morfology and cytology, structure, reproduction and types of yeast, bottom and top fermenting yeast. Brewer´s yeast collection and stress factors of the yeast are mentioned in the work. The crucial chapter about wort fermentation is talking about main fermentation process with indication of the factors influencing the fermentation and used technologies. Next parts of the chapter are dealing with aging of the beer and beer maturation and fermentation and aging in large containers with more specifications of beer production in cylindrical-conical tanks (CCT).
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