1,720,953 research outputs found
‘Get the simple things right and the big things take care of themselves’ studies on brewing yeast, fermentation and draught beer : 1979-2025
No full textThe work reported here between 1979 and 2025, spans the heyday and decline of
brewing science in the UK. The brewing industry was in rude health until the
publication in 1989 of ‘Beer Orders’ by Monopolies and Mergers Commission which
removed the ‘tie’ between breweries and pubs. This removed large swathes of
profitability and began the long march to decline. Technical centres were downsized
or closed and by 2000 the ‘big six’ UK brewers had either ceased brewing or were
owned by brewing companies from the USA, Belgium and South Africa.
Two themes are discussed: brewing yeast and fermentation (Chapters 2-5) and
draught beer quality (Chapter 6). The guiding principle to both studies is to ‘get the
simple things right and the big things take care of themselves’. The studies on yeast
and fermentation were mostly performed at Bass, the biggest of the then ‘big six’ UK
brewers. Although commercially driven, there were opportunities to publish less
sensitive work. Indeed, the various brewing conferences around the world encouraged
this and brewing science flourished with unspoken competition between brewing
companies for publications of quality, impact and influence.
The flavour and aroma of beer is important. It should be consistent, balanced and
reflect the brand specification. The industry was in significant growth in the late 70s
and, consequently, new large scale fermentation processes were introduced. This had
an impact on the production by yeast of esters and higher alcohols during fermentation
which distorted the aroma of the beer. The work outlined in Chapter 2 sought to better
understand the synthesis of these metabolites and to be able to better control their
formation. In both instances, their synthesis reflected the need to balance the flux of
intermediary metabolic cofactors, acetyl CoA/CoA (esters) and NADH/NAD (higher
alcohols). Yeast does what it does for good metabolic reasons and not to please the
brewer!
Yeast is an important contributor to the distinctiveness of beer, with different strains
making different beers. A key part of Chapter 3 is the process that was developed to
assure the identity and microbiological quality of yeast that was periodically ‘supplied’
to the Bass breweries. It was ahead of its time using cryogenic long-term storage of
production yeasts and DNA fingerprinting to validate (blind) the identity of each strain.
Allied to this work, is a study of the genetic instability of a major production yeast used
in two breweries, separated by 280 miles and some 10 years apart. Other work
considers the introduction of ATP bioluminescence to validate in real time the cleaning
of brewery vessels. This was a cultural change as the checking of the effectiveness of
the clean was performed by process operators and not the ‘white coats’ from the
Quality department. Adoption of the technology and its delivery is now the norm in
global brewing industry. The final piece in this Chapter describes some opportunist
research that explored the unexpected metabolism by brewing yeasts of the sugar
alcohol, mannitol.
Brewery fermentations need to be efficient, requiring sufficient but not excessive yeast
growth. The work in Chapter 4 considers the role of small amounts of oxygen added
at the beginning of fermentation for the synthesis of sterols, a lipid class that
determines the extent of yeast cell division and growth. Evidence is presented that at the beginning of fermentation, the yeast cell is unable to transport exogenous sugars
and that the metabolic fuel for this process is provided by glucose from the breakdown
of the storage carbohydrate glycogen.
At the time, the efficiency of fermentation and its management was a major driver of
research in the brewing industry. Although much of the work in Chapter 5 was
developed in the laboratory, we were fortunate that elements were evaluated at a
production scale. Initial work explored the relationship between oxygen and yeast
growth. This demonstrated that yeast strains require the addition of an optimal level of
oxygen to achieve the required fermentation performance and efficiency. Excess
oxygen resulted in excess yeast growth and less ethanol formation. An innovative
approach evaluated at a plant scale considered a more direct approach with the
oxygenation of yeast. Regrettably, a change in the approach for beer taxation
undermined this work which was not progressed further.
Brewery fermentations are unusual in recycling yeast from one fermentation to the
next. This can pose problems, as yeast quality can become compromised. Chapter
5.3 describes a ‘warm cropping’ process where yeast is recovered (‘cropped) from
fermenter two days earlier than is usual. This approach improved the physiological
quality of the yeast which – in extensive series of production fermentations – resulted
in a step change improvement in quality metrics. Further work on the cropping process
considered the heterogeneity of yeast cell populations. The age profile (and
associated cell size) of individual cells was of interest together with their selection
during cropping and subsequent performance in brewery fermentations.
On leaving Bass - now Molson Coors - in 2004, brewing science in the UK was sadly
in decline. Consultancy called and I became a ‘portfolio professional’ doing a bit of this
and a bit of that. A part time role at Heriot-Watt University was enjoyable but after eight
years there was appeal in working closer to home and, if possible, doing some
research. A role at the University of Nottingham achieved both objectives. Although
funding for yeast research was difficult, a new direction loomed.
As a consumer, I was aware that the quality of draught beer can be variable and
occasionally poor. With previous experience at Bass of dispense technology coupled
with being a microbiologist, it made sense to develop a research programme into the
factors that impact on draught beer quality. These studies are reported in Chapter 6
and, like some of the yeast studies, benefit from taking the work out of the laboratory
into the ‘real world’.
Draught beer systems are invariably contaminated with non-pathogenic
microorganisms (yeasts and bacteria) that can grow in beer. Low levels are not a
concern but the quality (flavour, aroma, clarity) of draught beer becomes progressively
compromised with greater numbers of microorganisms which attach to surfaces in the
dispense system as biofilms. Microbial contamination is managed by hygienic
practices, primarily line cleaning where the system is flushed with dilute caustic
solution. This is the weak link as the process is tedious and the recommended weekly
clean can – in many accounts - slip to two weeks or more. Measurement of quality
using a ‘forcing test’ (Chapter 6.3) was used with samples from public houses (Chapter
6.4) confirming that beer quality ranged from ‘excellent’ through ‘acceptable’ to ‘poor
and ‘unacceptable’. Other work modelled biofilm attachment and growth by microorganisms in draught beer (Chapter 6.5). The microorganisms in different styles
of draught beer from multiple public houses in different cities and towns exhibited a
core microflora (e.g. Brettanomyces, Acetobacter) with some specific to individual
styles (Chapter 6.6). In a parallel study, microflora were inoculated into different
commercial lagers and found to vary in susceptibility to spoilage. Greater spoilage was
associated with beers of higher pH and nutrient availability (Chapter 6.7). In a similar
study, the susceptibility to spoilage of alcohol free and low alcohol beers was
evaluated. These beers were more spoilable (rate and extent) than conventional
‘alcoholic beer’. Although alcohol free beers (AFBs) may require tuning for effective
pasteurisation, a greater concern is their delivery in public houses using draught
dispense. With the growth of the sector, brand owners are increasingly keen to serve
their beers in this way as it is more profitable than with bottles or cans. This is a
concern with these beers being more easily spoilt by microorganisms which will
compromise quality. A very different concern is the absence of alcohol will allow the
growth of some contaminating pathogens in alcohol free beer which is a significant
concern for food safety. The recommendation that AFBs are dispensed by bespoke,
stand-alone dispense systems has had limited take up which suggests there is need
for other approaches to minimise this particular consumer risk
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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