During fermentation, the yeast Saccharomyces cerevisiae produces a broad range of aroma-active esters that are important for the desirable complex flavour of beer. The sensory threshold levels of these esters in beer are low, ranging from 0.2 ppm for isoamyl acetate to 15-20 ppm for ethyl acetate. Although esters are only present in trace amounts in beer, they are extremely important as minor changes in their concentration may have dramatic effects on beer flavour. Therefore, optimization of the concentrations of these aroma-active esters in beer is of interest in beer brewing. The number and concentration of esters in beer may be influenced by the fermentation parameters, nutritional composition of fermentation medium and yeast strain type. Therefore, this study investigated the influence of fermentation temperature, pH, and wort nutritional supplements (amino acids and zinc) on the production of yeast-derived ester compounds. In addition, the overall fermentation performance was evaluated based on the reducing sugar and Free Amino Nitrogen (FAN) utilization, ethanol production and yeast cell density. These parameters were analysed using the Dinitrosalicyclic acid method, Ninhydrin assay, Gas Chromatography and standard spread plate technique. The concentration and stability of ethyl acetate, isoamyl acetate, phenyl ethyl acetate, ethyl hexanoate, ethyl decanoate and ethyl octanoate was monitored during storage at 4 °C and room temperature (RT), in the final beer by Chromatography. The expression levels of the ester synthetase genes under conditions that resulted in the highest increase in ester production were quantified by Real-Time PCR. For the lager beer, the best fermentation performance was achieved at RT (±22.5°C), resulting in the utilization of the highest amount of nutrients and production of 4.86% (v/v) ethanol. This was accompanied by the highest production of acetate and ethyl esters, which were 40.86% and 87.21%, respectively, higher than that of the control. Spent yeast density ranged from 2.492 to 3.358 mg/ml for all parameters tested, with the highest yield produced when wort was supplemented with 0.120 g/l zinc sulphate. Fermentations at 14 °C yielded the highest foam head stability and spent yeast viability with a foam head rating of 2.67 and a spent yeast viability of 3.85 × 107 cfu/ml. Ester compounds were relatively stable at 4 °C than at room temperature decreasing by only 7.93% after three months. Of all the volatile esters produced, ethyl decanoate was the least stable, with a 36.77% decrease in concentration at room temperature. For the ale beer, the best fermentation performance which resulted in the highest nutrient utilization was achieved when wort was supplemented with 0.75 g/l L-leucine resulting in the utilization of the highest amount of nutrients (51.25% FAN and 69.11% reducing sugar utilization) and production of 5.12% (v/v) ethanol. At the optimum fermentation pH of 5, 38.27% reducing sugars and 35.28% FAN were utilized, resulting in 4.32% ethanol (v/v) production. Wort supplemented with 0.12 g/l zinc sulphate resulted in 5.01% ethanol (v/v) production and 54.32% reducing sugar utilization. Spent yeast density ranged from 1.985 to 2.848 mg/ml for all parameters tested with the highest yield produced when wort was supplemented with 0.120 g/l zinc sulphate. This was also accompanied by the highest yeast viability of 2.12 × 107 cfu/ml achieved on day 3 of fermentation. Supplementation with 0.75 g/l L-leucine yielded the highest foam head stability with a rating of 2.67. Overall, ester compounds were relatively more stable at 4 °C than at RT decreasing by only 6.93% after three months, compared to a decrease of up to 16.90% observed at RT at the same time. Of all the volatile esters produced, ethyl octanoate was the least stable, with a 32.47% decrease in concentration at RT, phenyl ethyl acetate was the most stable ester at RT, decreasing by 9.82% after three months. Wort supplemented with 0.75 g/l L-leucine resulted in an increase in isoamyl acetate and phenyl ethyl acetate production by 38.69% and 30.40%, respectively, with a corresponding high expression of alcohol acetyltransferases, ATF2 (133.49-fold higher expression than the control). Elevation of fermentation temperature to RT resulted in the upregulation of ATF2 (27.11-fold), and producing a higher concentration of isoamyl acetate. These findings indicate that ester synthesis during fermentation is linked to both substrate availability and the regulation of gene expression. Therefore, it would be possible to manipulate the expression of certain ester synthestase genes to create new yeast strains with desirable ester production characteristics. Results from this study also suggest that supplementing wort with essential nutrients required for yeast growth and optimizing the fermentation conditions could be effective in controlling aroma-active ester concentrations to a desired level in beer. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2011.

Thesis (M.Soc.Sci.)--University of Waikato, 2007. / Title from PDF cover (viewed March 31, 2008) Includes bibliographical references (p. 128-135)

The aim of this dissertation was sensorial evaluation of non-alcoholic beers according technology of their production. Ten samples of non-alcoholic beers from different breweries were tested with sensorial analysis. Non-alcoholic beer Lobkowitz Premium and Radegast Birell were made with help of special types of yeasts. The rest of non-alcoholic beers was made by technology of controlled fermentation. Non-alcoholic beer Samson made by method of controlled fermentation gained the first place and Radegast Birell made with help of special types of yeasts gained the second place. It is not possible to specify, which one from used technologies of producing non-alcoholic beers have got a proven positive effect on the sensorial quality of beer, from identified data. Sample D (Samson) reached maximum values of complex perception of aroma, fullness, briskness and character of bitterness in sensorial evaluation of chosen criterions. The highest value of complex perception of taste was recorded at sample J (Radegast Birell). On the other hand, sample F (Budweiser Budvar) reached the lowest values of fullness, briskness and komplex perception of taste. The lowest values of komplex perception of aroma was noted in sample G (Dudák) and sample C (Bernard) had got the lowest values in complex perception of character of bitterness. Samples B (Platan) and D (Samson) contained additional sweetener E 954 (Saccharin). Saccharin is weaker than standard sugar but it leaves a bitter taste behind after ingestion. Men perceived sample B (Platan) in terms of aroma and taste negatively and in term of character of bitterness positively. Women registered only minimal differences in perception of aroma, intensity of taste and character of bitterness in this sample. Used sweetener could inluenced men´s view on taste because of its bitterness. The conducted survey also showed that in situations where the respondents can not give alcoholic beer , 80 % of men´s surveyed by opting for non-alcoholic beer . On the contrary, 87 % of women would prefer a different soft drink.

Orientador : Roberto Herminio Moretti / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-08T03:33:12Z (GMT). No. of bitstreams: 1 Mattos_RubensCelsoFonseca_D.pdf: 1401159 bytes, checksum: 84408c8147daaed58dbb2cd690ed6cd5 (MD5) Previous issue date: 2007 / Resumo: A cerveja tipo Pilsen é líder de vendas no mercado mundial. Ocorre mundialmente a tendência de se produzir cervejas Pilsen com menos amargor, menos corpo e mais claras. O grande desafio atual da indústria cervejeira é a garantia do frescor e leveza desse produto durante todo o seu tempo de vida de prateleira. Com a globalização, as cervejas são transportadas para distâncias cada vez maiores, causando a demanda por um produto que contenha vida de prateleira estendida, ou seja, grande estabilidade sensorial. Níveis mínimos de aromas e sabores indesejados são facilmente percebidos pelo consumidor, pois os teores de amargor, corpo e álcool são insuficientes para mascará-los. Neste trabalho foi avaliada a influência de importantes variáveis sobre a estabilidade sensorial da cerveja Pilsen. Os efeitos da temperatura, da incidência de luz e da agitação durante o transporte da cerveja, bem como da interação entre eles, foram quantificados e, pela primeira vez, comparados estatisticamente. A literatura cita a influência destas variáveis, mas sua quantificação, interação e comparação, não estão relatados. Os resultados mostraram que a influência da temperatura sobre a estabilidade da cerveja é muito maior que os efeitos de agitação e de incidência de luz. Esses dois últimos, por sinal, têm pouco ou nenhum efeito sobre a estabilidade sensorial do produto. Esses resultados foram validados estatisticamente, tanto por provadores treinados de uma cervejaria comercial, quanto por consumidores comuns. Em oposição ao resultado sensorial, a formação de trans-2-nonenal se mostrou mais influenciada pela incidência de luz e pela agitação, do que pela ação da temperatura, reforçando a corrente de que o teor de trans-2-nonenal não é, por si só, um bom indicador da estabilidade sensorial da cerveja. Este trabalho traz, ainda, uma ferramenta inédita e muito importante para a tomada de decisões por parte dos cervejeiros. Decidir se uma cerveja pode ou não ser liberada para consumo é uma das tarefas desses profissionais. O critério de liberação pela análise sensorial do produto leva um grau muito alto de subjetividade. Primeiramente, é apresentada uma visão do grau de aceitação do consumidor em relação à oxidação da cerveja, representada aqui pelos níveis dos atributos papelão, caramelo e metálico. Provadores foram treinados usando a técnica de Análise Descritiva Quantitativa (ADQ), para avaliação sensorial desses três atributos. A combinação da análise estatística dos resultados dos testes de aceitação com os resultados da equipe de ADQ permitiu a construção de um modelo matemático, que é uma ferramenta adequada para a decisão objetiva quanto a comercializar ou não uma cerveja. Com essa ferramenta se elimina a subjetividade da decisão do provador, por mais técnica e respeitada que esta seja na indústria de cerveja. Dentre os atributos sensoriais utilizados para descrever a oxidação da cerveja, a intensidade do atributo papelão é a que tem maior correlação com a estabilidade sensorial do produto. Os atributos caramelo e metálico não apresentaram correlação nem com a opinião dos provadores treinados da cervejaria nem com a aceitação dos consumidores / Abstract: Pilsner is the type of beer produced the most worldwide. There is a global trend to produce beers that are not exactly like the original Pilsner beer: less bitter, less body and paler. The most challenging problem for the breweries at the moment is to guarantee the freshness of this beer during its shelf life. Global sales and markets result in beers being distributed to longer distances and this demands a longer shelf life with high flavor stability. Consumers easily detect minimum contents of off-flavors because the low bitterness, low alcohol content and low body are not capable of masking them. In this work the influence of important variables on Pilsner beer flavor stability was studied. The impact of temperature, exposure to light and shaking during transportation, as well as the interaction between them, were quantified and, for the first time, statistically compared. The current available reports mention the influence of these three variables over the beer quality, but it is not clear witch is the most important nor how is the interaction between them. According to the results obtained here, the temperature plays a major role when compared to shaking and light exposure. In fact, the former two effects showed to have low or even no effect on the stability of the product. Both a trained panel of a commercial brewery and regular consumers had statistically validated this conclusion. Oppositely, the formation of trans-2-nonenal is more influenced by light exposure and shaking than by temperature. This reveals that the content of trans-2-nonenal is, alone, not enough to express beer flavor stability. This thesis also brings a unique sensory tool to be used by the brewers to decide whether a supposedly oxidized beer can or cannot be dispatched to market. Currently, this decision is made on a subjective basis by judging the freshness of the beer or even the freshness it might present during its shelf life. Judging how much a beer is oxidized is not a simple task and most of the time this is done by only some brewers (sometimes only one), what increases the risk. The acceptance by consumers is here related to the beer oxidation, represented by the attributes papery, caramel and metallic. Subjects were trained to judge the contents of these attributes in the beer using the Quantitative Descriptive Analysis (QDA) technique. The statistical combination of the results of the beer acceptance and the results of the QDA allowed the construction of a mathematical model for deciding objectively about selling or not a beer. With this tool the subjective decision of the taster is eliminated, even though this it is commonly practiced and respected in the beer industry. Concerning the beer attributes used in this work to describe the beer oxidation, the intensity of the attribute papery is the one that is more strongly correlated with the flavor stability of the product. The attributes caramel and metallic do not correlate neither with the opinion of the trained panel nor with the acceptance by the consumers / Doutorado / Doutor em Tecnologia de Alimentos

The dissertation is one of a number of contributions to the research of a rather new form of tourism - beer tourism, or gastronomy tourism in a broader context. In the first part of the dissertation, the topic is grasped theoretically. Firstly, beer tourism is defined as one of the alternative forms of spending leisure time, and it is classified within tourism typology, alongside the better-known wine tourism. Tourists currently prefer the alternative forms, with an emphasis on, besides other things, tradition, authenticity and experience, which make up the values typical for participating in beer tourism. In spite of this form being at the start of its expansion in the Czech Republic, in the last few years, its dynamic has been immense, which is documented by plain statistics. In the past 3 years, almost half of the current 340 Czech breweries have been established. Further in the text, the product of beer tourism is defined and its typology is created, by which the supply side of tourism on the level of the Czech Republic as well as the Liberec region is later analysed. The second part focuses on the assessment of a questionnaire survey, with the objective of assessing the respondents' perception of the beer market and tourism in the Liberec region. The questionnaire survey is followed up by...

Final thesis focuses on strategic and financial analysis of Pivovar Janáček, a.s. Strategic analysis researches the beer market in the Czech Republic. Thesis analyzes beer industry and its role in OKEC, beer consumption, beer production and structure of the beer market in the Czech Republic. Furthermore is analyzed labeling beer, taxation of beer and export of beer. Financial analysis deals with horizontal and vertical analysis of financial statements, analysis of liquidity, rentability, activity, debt ration and also analysis of predictive models. Perspectives of the company are summarized according to previous analysis in the conclusion.

Craft brewing has seen a remarkable growth, from the first steps in the late 1960s in the USA until today. Breweries in the USA and Western Europe saw a long period of brewery fusions, concentration and closings from after the 2nd world war until roughly late 1990s/early 2000s. This trend also affected Sweden, where a market with smaller breweries in almost every town or municipality ended up in a situation with a dominating giant. The emerging craft breweries have totally changed this picture. Previous research has shown that craft brewing often starts as a hobby and evolves over time to a commercial business. The process for how these breweries fund themselves at the time of establishment has been researched in several papers, but how breweries that get past the initial step, start to grow and need additional capital to remove some of the bottlenecks that occur is considerably less examined. Since craft brewing is a unique business and the research in Sweden is scarce, theories and practises from small and medium enterprise (SME) financing have been applied. By using semi‐structured interviews and a thematical analysis, six craft beer brewery representatives were interviewed about their own perceptions of the methods they chose to overcome their financial obstacles, both initially but also when experiencing growth and needs for expansion. The breweries were chosen from a combination of size and geographical position in Sweden. Some of the breweries are situated in rural and some in urban areas. All the breweries fulfil certain financial criteria, and experienced production bottlenecks that needed to be solved financially. The thesis arrives at the conclusion that each microbrewery had its unique set of circumstances. The chosen financial solutions were affected by the owner’s perceptions and previous experiences. This supports previous research where new business establishment is highly depending upon the owner or the owner’s own money, which can partly also be explained by how the owners initially looked at their business (hobby/part hobby versus the intention to immediately start a commercial business). Raising capital for further expansion gives a diversified picture meaning that classical financing theory is only partially applicable on the craft brewing industry.

This work examined the role of the craft brewers of Florida in creating alternative economies. This work argues that craft brewers function in ways that they can create a space in which other, smaller entities might then take advantage. Craft breweries' expansion, and continued success rests on the ability of the brewer to harness the power of transformation, the prism effect, or the refaceting of a space with different meanings. Craft breweries meet many of Jacobs' (1961), as stated in her seminal work, conditions for diversity in the city, especially in the role of self-government. Craft brewers function as informal forms of government for communities, by making smaller entities more visible, by serving as a warrior and weaver for political action in the city, and offering subversive defiance, by which they subtly challenge the dominant disconnected economic structure. Craft breweries serve as a way to create an embedded economy, or as a way of grounding local businesses, social issues, and individual actors together. In this way, the research addressed deeper ethical issues that transcend the idea of craft brewing in general, that the success of craft brewers reflects a form of activism, and a visible way for individuals to circumvent the global processes which left them disengaged in their community. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

Thesis (M.Sc. (Microbiology)) -- University of Limpopo, 2018 / Beer is one of the most widely consumed alcoholic beverages in the world. The brewing process is based on natural enzymatic activities that take place during the malting of barley grain, mashing of grist and fermentation of wort. Insufficient malt enzyme activity during the mashing process leads to high levels of barley β-glucan, arabinoxylan (AX) and dextrins in the wort as well as in the final beer. It was reported that high levels of β-glucan and AX increase wort and beer viscosity which lower the rate of beer filtration and this negatively affect the production rate in the brewery. During beer fermentation, brewing yeast catalyses the conversion of wort sugars to ethanol, carbon dioxide and other metabolic products. However, non-fermentable carbohydrates i.e., limit dextrins remain in the wort and final beer. These non-fermentable carbohydrates are known to contribute to the caloric value of beer which might lead to weight gain in consumers. The objectives of this study were to evaluate the effect of recombinant yeast strains expressing an endo-β-1,4-glucanase or an endo-β-1,4-xylanase on beer viscosity (as an indicator of filterability) and an α-amylase on residual sugars levels. The effect of the above mentioned enzymes on the aroma, appearance, flavour, mouth-feel and overall quality of the beer was also determined. Wort was produced in the University of Limpopo micro-brewery and the wort was pitched with different recombinant strains. The wild-type strain served as control. The results obtained showed that the xylanase expressing strain produced a measurable decrease in viscosity over the course of the fermentation, but endo-glucanase did not have any effect on the beer viscosity. The α-amylase producing strain, did not show a measurable reduction of residual sugars in the final beer probably as a result of very low activity on α-1,6 glycosidic bonds in dextrins during fermentation. The xylanase and α-amylase producing strain fermented effectively with good attenuation (decrease in wort specific gravity). The beer produced by the α-amylase and control strains were preferred in terms of taste and had similar qualities. The secreted amylolytic activity was not sufficient to significantly reduce residual sugar in the final beer. Although the xylanase secreting strain produced a beer with lower viscosity, the enzyme had a negative impact on the taste of the beer. Key words: Brewer’s yeast, beer fermentation, low calorie beer, amylase, xylanase, endo-glucanase.

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.