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This thesis deals with the variability of hop oils in the hop cones. Hops is the most important raw material for the production of beer and hop oils are the most important group of compounds responsible for the aroma of hops and thus the beer. Essential oils are applied in commercial quality assessment of cone hops for beer production. Essential oils have also hop buffer and antibacterial effects and pharmacology are used for suppressing agitation, restlessness and insomnia. Essential oils are complex mixtures of hundreds of natural compounds of different chemical composition. They represent a mixture of carbon compounds, oxygen compounds and sulfur compounds. The content of hop oils in the hop cones depends on the genetic characteristics of the variety, growing area, the average temperature, rainfall, and other conditions cultivation. This work was performed by steam distillation determination of hop oils. The determination was carried out on samples from 2012 and 2013, the essential oil content was profitable in 2012. Highest value of the hop oils was measured in a variety of Premiant from Tršice growing region (837 micro liters.100g-1). The lowest value then the variety Saaz classical form of the Saaz hop-growing area (220 mocro liters.100g-1).

The diploma thesis deals with sensory assessment, measurement of color and pH of six batches of hop shoots, which differ harvest days and pasteurization, dipping in water overnight and repeated pasteurization. Young shoots of hops were harvested during April. It is a pasteurized product from sweet-sour pickled hop shoots. Results of sensory assessment of hop shoots showed between batches a statistically significant difference (P <0,05) in a number of descriptors. Results of sweet-sour pickle did not showed differences between batches. The difference between batches was only for the purity descriptor. The term of harvest shoots may affect the sensory quality of hop shoots. Dipping of shoots overnight in water and the long-term effect of the pasteurisation temperature worsened the texture and color of the shoots.

The aim of this thesis is to summarize the options of hop products leaded by hop extracts. The literature research focuses on chemical composition of hop, key transformation of hop bitter acids used in the brewing industry and also describes the technology of production of individual hop preparations and possibility of their application. The next part summarizes the beer production process including associated mikrobiology, which is an importand part of all stages of beer production. The experimental part describes production of six variations of beer chosen from different hop products, their chemical analysis and sensory evaluation. The results of the tests are evaluated statistically and are compared with each other at the end of the thesis.

In this thesis, "The Evaluation of the Quality of Hops from Traditional and Non-traditional Growing Areas", the quality of three varieties of hop seed cones (Saaz, Sladek and Kazbek) from a non-traditional hop-growing region was analyzed and the data used for comparison. The primary aim of the study was to determine if there is a possibility of growing quality hops in a region that is not considered a hop-growing region. The hops that were tested were harvested in 2015 from a private hopfield located in Obora near Tábor. This hopfield is owned and managed by Ing. Martin Novák. Mechanical and chemical analysis was carried out on samples from Obora. The main goal of the analysis was to determine the alpha and beta acid content of the hop seed cones harvested there. Samples were analyzed with EBC 7.7 (HPLC). Alpha acid content of the tested samples in Saaz hops was 4.06 % w/w, in Sladek 7.14 % w/w and in Kazbek 4.67 % w/w. The content of beta acids in Saaz hops was 3.16 % w/w, in Sladek 3.93 % w/w and in Kazbek 4.51 % w/w. The collected data was then compared to published data for hops grown in traditional hop-growing regions. Alpha acid content was found to be higher in the hops grown in Obora, while beta acid content was lower.

This diploma thesis discusses about technology of beer hopping. The first part describes beer history, beer brewing, hops and hop products. The second part deals with the practical beer brewing using different hop technologies. Seven different beers were brewed using the same dose of the same hops and one using the hop extract. IBU values were determined by calculation and spectrophotometer. A sensory analysis of the resulting beers was also carried out. It has been proven that different beer hopping technologies have shown a positive change in the resulting bitterness of beer. The best taste was the beer brewed with shortened hoping.

The aim of this thesis is to introduce hops harvest phenomena as a special kind of agriculture aid in socialist Czechoslovakia. The aid consisted of secondary school students in the 1960s. The thesis describes organization of hops harvest, process of harvesting work and after-work activities of temporary staff. This thesis contains occurrences of August 1968 in Czechoslovakia. The harvesting work was complicated by raid of Soviet Army in this year.

Study of sensory-active compounds of hops in dry-hopped beers Key words: hop, hop oils, dry-hopping, beer, beer-aging, beer sensory analysis Nowadays, dry-hopping is a widely used method of beer making, with its pros and cons. The main purpose of dry-hopping is to derive specific hop aroma to beer in its very unchanged form. The essential part of this work consists of a study of hop essential oils, as the main providers of desired hop aroma. Firstly, the validation of methods for isolating essential oils from hop material and beer is carried out. Secondly, the transfer of these volatiles in process of dry-hopping is studied and the impact on beer aroma profile is discussed. Subsequently, changes of essential oils profile during beer-aging are observed and evaluated with a valuable tool, the sensory analysis. This study was realized on beer samples from Brewers' Choice program, thanks to the Research Institute of Brewing and Malting and Lenka Strakova, the Pilsner Urquell brewer.

The thesis is focused on the effect of dry hopping on beer senzomy and sensory profile of the top-fermented beer. The goal of this work was to modify samples of the top-fermented beer by dry hopping, to analyze them by senzomy and sensory way, to optimize the method for hop essential oils analysis and to compare the results to the available literature. The problematics of the used raw materials, analyzed substances, technological and analytical methods are discussed in the theoretical part. The practical part is composed of technological preparation of the samples and their analysis. There was used a commercial product of the type of American Indian Pale Ale in this work. There was added a Cascade hop by dry hopping into the commercial product. The basic analysis of gravity and attenuation of the beer were done on the fresh beer and the two months old beer. The selected essential oils, carbonyl compounds, bitter acids, selected metal contaminant and nitrates were established in the beer and in the hop. The samples of the beer were sensory evaluated in the same two-month interval. It was determined that the dry hopping influenced the increased pH of the beer. There was established the quantity of essentials oils in the samples and it was compared to the sensorial results. These results can be used as a base for the next exploration, some part of the results are applicable in the beer industry.