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Technical abstracts.

Technical Abstracts

An analysis of photometric color intensity measurement, in general, and then color measurement specifically, to meet ASBC and EBC, Beer and wort has absorption in the ultraviolet, violet, blue, and green visual band of the electro-mechanical spectrum. This roughly corresponds to a cut-off of frequency 430 nanometers. By measuring the intensity of this frequency in a beer or wort sample, it is possible to determine the amount of color intensity in the sample directly without using the visual comparison method or off-line techniques. Color in-line monitoring equipment for both beer and wort useful for production and quality assurance will be described. The common interference to this measurement is Haze (turbidity or suspended particles). There will be a table on the various types of beer, ale, etc., and their color EBC, ASBC units using laboratory or on-line measurements.

New Packaging Lines with High Productivity

Suntory's Tonegawa Brewery placed its new bottling and canning lines into operation in the spring of 1989. These two lines consist of elaborately designed machines connected to the latest information gathering system, and are operated by highly trained operators. The main considerations in designing to realize high productivity were as follows:

1. High reliability: Our engineers analyzed the previous data and the deficiencies with the existing machines, and established requirements for each machine in detail. At this step the experiences of line operators as well as IE analysts were of great use.

2. Introduction of automated machines: We incorporated empty bottle inspectors and liquid level inspectors of our own development into the line. Further, we developed the automated foreign bottle inspectors which detect and sort different shaped bottles before washing.

3. Job enlargement: Shop rotation and maintenance training strengthened a mutual assistance structure between bottling and canning personnel, contributing to flexibility in management.

4. Concentration: Machine layout and information systems were designed with the concept that both machine and information should concentrate around man as the center, which reduced time from recognition to resolution of each machine's malfunction, if any.

Beer Foam Physics

Foam stability is determined by the process of four physical processes. They are bubble formation, drainage, coalescence and disproportionation. Bubble formation in beer can either occur by heterogeneous nucleation or by air entrapment. As a result of heterogeneous nucleation, small carbon-dioxide bubbles arise. By air entrapment larger bubbles are generated. Next, foam disappears by the action of the three other physical processes. Drainage is the liquid flow from the foam to the beer as a consequence of gravity and capillary forces. On account of drainage foam volume decreases, foam becomes drier and the thickness of the liquid films between the bubbles decreases.

Coalescence is the merging of two bubbles as a consequence of film rupture. This leads to coarsening and collapse of form. In general, coalescence doesn't play a significant role in the breakdown of foam, unless fat-like components are present.

Disproportionation is interbubble gas diffusion caused by pressure differences in the foam. This action results in coarsening of the foam. Gas diffusion from the foam to the atmosphere is the principal cause of the high partial pressure gradient of carbon dioxide.

The characterization of foam is complex and therefore it is not possible to describe foam with one foam number. A new optical glass-fibre probe technique has been developed with which several foam characteristics can be measured. Namely: 1. The bubble size distribution as function of time. 2. The collapse of the foam, that means the foam height. 3. The drainage of foam. 4. The overrun.

By using the knowledge about the four physical processes several beer foam phenomena can, at least qualitatively, be explained.

The Importance of pH Control During Brewing

There is a tendency for pH of wort and beer to be accepted as a consequence of brewhouse and fermentation procedures, rather than emphasis being placed on the mechanisms for pH control representing a major element of brewing process control.

The control of pH during wort production has significant impact on brewhouse performance and wort composition. Data has been compiled from small-scale experiments and production trials to illustrate the impact of pH variation on extract recovery, wort protein and carbohydrate content and mash bed permeability.

Mechanisms determining pH control during fermentation have been investigated and the influence of wort composition in terms of amino acid/small peptide composition on beer pH and potential haze stability and head formation has been explored on laboratory, pilot-plant and production-scale. The results obtained have allowed conclusions to be made regarding the relative significance of factors stimulating yeast growth and wort buffering capacity on beer pH, and consequent influence on beer flavor stability.

Volatile Flavour Compounds in Low Alcohol Beers

Development of low alcohol beers (less than 3.5 percent by volume) for this increasingly important segment of the Australian market has necessitated extensive evaluation of techniques for producing such beers, in particular fermentation, reverse osmosis and vacuum evaporation. While each of these has advantages, all result in significantly reduced concentrations of volatile flavor components (esters, alcohols, short chain fatty acids) compared with full strength beers. These concentrations are determined by the alcohol concentration in the product, by the process and by the operating conditions used. Comparative data shows the first of these to be the principal factor in the concentrations of volatile components in the final product.

The Flavor of Beer

At some point in the recent past we acquired a critical mass of accurate scientific information about the flavor elements of beer. This paper attempts to unravel how those elements interplay to produce the great beer types of yesterday and today, with some suggestions for beers of the future. Rules and pitfalls of analytical taste testing are discussed, also those of tasting by consumers. For each flavor element, the author reviews how it was defined with the aid of model experiments with added and purified substances, and how we assume the elements interact to produce the overall flavors we know.

A Method for the Rapid Evaluation of the Colloidal Stability of Beer

The prediction of the colloidal stability of beer is usually made using a forcing test. This test involves heating beer samples for several days, sometimes with intermittent cooling, followed by chilling before reading turbidity at a low temperature. It usually takes one week to obtain results.

We have developed a rapid (two-hour) assay for colloidal stability that correlates well to forced chill haze even over a variety of conditions. These conditions include beer age, beer type, chillproof treatment level, and chillproofer type.

Published quick tests were examined to determine their relationships to the Forced Chill Haze Test, and to determine their weaknesses. These were the Saturated Ammonium Sulfate Precipitation Limit Test (SASPL), the Ammonium Sulfate Haze Test, the Alcohol Cooling Test (Chapon), and the Cooling Test. No one test by itself was adequate: each was sensitive to one variable or another.

The forced chill haze results can be predicted using a mathematical combination of two simple, easy tests: the Cooling Test and the Ammonium Sulfate Haze Test. One scaling factor may need to be empirically determined given certain interferences. These interferences will be discussed.

Product Integrity Through Superior Filling Technology

Never before has the filling equipment manufacturer been confronted with such exacting standards as with the recent proliferation of specialty beers. The demands for maximum product integrity required and prompted refinements of virtually all phases of the filling process. As a result, filling systems are configured with the latest technology of control/design and continuous monitoring to suit exact customer standards.

Filling valve performance is widely considered the most important phase of the filling performance; it has constantly been refined as technology advances. Equal emphasis must also be placed on: 1. Precise product level and pressure control in the bowl. 2. Control and maintenance of head space purity. 3. Smooth and efficient bottle transfer to crowner. 4. Consistent jetting of filled bottles before crowning. 5. Precise closing of filled bottles.

Together with new, fresh approaches to peripheral control and monitoring systems, maximum product integrity and "Same as Brewed" results can be achieved.

Air Ingress Through Bottle Crowns

Ingress of oxygen into bottles of beer was studied by measuring the oxygen and nitrogen content of bottles with respect to time. The method consisted of piercing the crown with a modified Zahm-Nagel device, removing the carbon dioxide with a gas chromatograph and measuring nitrogen and oxygen with a mass selective detector.

Crowns were lined with commercial PVC compounds with different plasticizers, blend of PVC with low permeability polymers, and low permeability polymers themselves. Test packs were prepared at five different brewers.

It was demonstrated that: 1. Air measurements as a measure of oxygen are meaningless. 2. Nitrogen measurements are only valid when the relative permeability to oxygen is unknown. 3. Plasticizer and liner design can effect oxygen ingress. 4. Blending PVC with compatible low permeability polymers are costly, hard to process and detract from functional performance.

New compounds were designed to intercept oxygen during ingress. Experimental crowns were compared with commercial crowns.

For the new compounds: 1. Nitrogen ingress is independent of oxygen ingress. 2. Mocon measurements indicate an oxygen ingress of zero can be attained. 3. The new compounds process and perform similarly to commercial compounds.

Advanced Method for Coating Scuffed Glass Bottles

The returnable glass bottle is an energy-saving container. However, repeated use unavoidably causes scuffing in the bottle which spoils appearance of bottled beer or soft drinks. Consumer complaints, also, are raised on scuffed bottles.

Asahi developed emulsion type coating silicone jointly with a silicone producer and a coating apparatus by Asahi itself in 1981. Coating chemicals and coating apparatus have been improved since then. In 1986, we found that ethanol solvent gave special features to coating chemicals; quick-dry; non-slippage; water resistance; complete removableness in bottle washing process; and harmlessness to the contents of a bottle. Ethanol was replaced by polydimethylsiloxane in 1989. The new solvent was less inflammable and safer for the working environment than the former solvent. As a result of these improvements, we obtained a satisfying coating chemical which hardly got whitened through abrasion during transportation.

A Review of Non-Oxidizing and Oxidizing Biocides as Alternatives to Chlorine for Biological Control in Pasteurizer Systems

Due to its effectiveness and cost, chlorine is the most widely used biocide in industrial cooling water systems. Throughout all industries, an increasing number of concerns over the use of chlorine are occurring. Some concerns expressed by the brewing industry include high corrosion rates at biocidally effective dosages, safety in storage and handling, and a reevaluation of a long-term cost of using chlorine.

Alternatives to chlorine, both oxidizing and non-oxidizing, will be reviewed relative to their ability to meet the needs of the brewing industry.

Management of Control Systems Software Development and Costs

Industrial computer-based control systems have increased their capabilities by an order of scale from the days of simple relay replacement to the sophistication process control systems used in most breweries today. This has caused a dramatic increase in the amount of complex programming required to control production processes at optimum efficiency, provide management with current production information, and provide in-house staff with maintainable systems.

This paper will identify the areas of increased complexity of control software and the requirement to satisfy the diverse needs of Management, Operations and Maintenance. These will include the continuing requirements for system fine-tuning to enhance the long-term viability of the process by ensuring that quality, quantity and cost goals are constantly improved.

The first section of our paper will examine such typical problems as: Rate of change of technology, Intelligent devices and interfaces, Scope changes, Optimism and lowest cost philosophy.

The main section of the paper will then deal with Project Management and cover: Identifying the real need, Team selection, System definition, Software standards, Programming, program testing, Commissioning, Revisions and Fine-tuning.

Recent Advances in Conveyor Lubrication

Brewery filling operations are continually changing. Larger production plants require higher filling rates. New brewery products require careful attention to sanitation and control of microbiological contamination. Stricter environmental and safety regulations require careful attention to storage, handling and disposal of products used in the brewery.

Conveyor lubricant technology has changed to meet the changing needs of today's brewery operations. Key needs include: 1. Improved lubrication for high-speed chains. 2. Elimination of soil on conveyors. 3. Control of microorganisms on conveyors, especially in the filler area. 4. Foam control in bottle inspection area. 5. Foam control under and around conveyors. 6. Prevention of nozzle plugging. 7. Safe storage and handling, and container disposal. 8. Cost control. 9. Effluent control. 10. Container compatibility.

Stainless Steel and Corrosion in Brewing Vessels

Stainless steel has been commercially available for approximately 40 years and has become the prevalent material of construction in the brewing industry. The stainless steel family has grown into a 62-alloys class with various attributes.

The criteria for selection of a specific grade of stainless steel should be determined prior to any fabrication. The criteria of selection is typically based on its operating environment and surface finish requirements.

A knowledge of various types of corrosion in different environments can prevent premature failures or shortened life expectancy of vessels.

Stainless steel has its limitations, but when proper material engineering is practiced, it is recognized as the material of choice in fabrication.

The DMS Story

DMS can arise in beer in different ways: the breakdown of the percursor SMM (S-methyl methionine), by yeast metabolism, by chemical liberation during fermentation or by bacterial contamination. We have worked on all of these points.

A great part of the SMM is degraded to DMS during kilning and evacuated with the kilning gases. During brewing another part of the SMM is degraded to DMS following a first-order reaction. The DMS formed must be eliminated by evaporation. During fermentation, there is no further degradation of SMM to DMS. Moreover, a great part of the DMS is evacuated with the CO2. However, we measured an increase in DMS content in some cases. This is due to the degredation of DMSO, another precursor of DMS. Forced experiments have proven that many brewery yeast strains have the capacity to reduce DMSO and DMS.

For controlling the content of DMS in the finished beer we have different areas of possible intervention: 1. Choosing a malt with a low SMM content. 2. Boiling long enough with efficient evaporation and a wort hot stand as short as possible. 3. Selecting a yeast strain that does not produce DMS during fermentation.

Developing Designer Barley

The tremendous progress made in malting barley improvement over the past 100 years has occurred without the benefit of tools that will allow for the systematic assembly of traits implied by the term "designer." Breeders now have tools at their disposal-tissue culture strategies, DNA-level gene mapping, and sophisticated statistical software that allows for the identification of chromosome regions involved in expression of "quantitative" traits. Examples of such traits are yield and various components of malting quality. Analysis of DNA-level variation in recombinant inbred populations should allow for the "marking" of the "quantitative trait loci" (QTL) that control these traits. Breeding by design will be achieved by advancing to extensive field test only material that carries desired markers. Efficient, direct non-sexual transfer of genes to barley that are not naturally occurring in the species should be feasible in the near future. Technique limitations are likely to limit its application to "qualitative" traits controlled by single genes - herbicide and certain insect resistance genes are examples. The systematic assembly of quantitative and qualitative factors should allow breeders to maintain impressive rates of malting barley improvement.

Recent Development in Mash Separation

For various reasons, the brewing industry changed from insitu-mash separation in deep bed mashtuns into the principle of stirred and transferred mashes with the immediate mashes with the immediate consequence that filter bed depth had to lowered drastically from approximately 1.5 m to 0.3 - 0.4 m.

An overview is given of the evolution from medium-deep-bed-lautertuns to a new generation of thin-bed-filters, from the Nordon HP filter to the latest propositions.

The objectives are: clear worts, independent of the presence or absence of husks, flexibility with regard to raw materials, shortest operational time from mashing in wort cooling.

Preset conditions:

For stirred and transferred mashes preset conditions for industrial mash filtrability are discussed. They are fully in line with the newest recommendations in view of improved flavor stability.

Practical Investigations on the Possible Impact of Mash-Separation-Time on Beer-flavor

This study is part of a long-term research-project in view of improved flavor-stability. One of the objectives is to evaluate the effect of fractionated milling, the husk-fraction and of husk-contact-time on beer-flavor and flavor-stability. With newly developed thinbed-filters shortest contact-times proved to be possible, independent of the presence or absence of husk-material. It appears from trial-brews that shortest contact-times during mash-separation and sparging help in lowering the TBA-values of cold wort and consequently in beer. The overall effect is positive with regard to flavor-stability. The participation of specific husk-components in Strecker- and Maillard-reactions as well as in lipid-metabolism might well explain lower TBA-values for beers produced with shortest husk-contact time and/or with a low husk-content in the mash.

The Brewer's Control of Yeast Multiplication

The practical measurement of the difference between amount of yeast added to the wort and the amount of yeast collected from the beer is difficult, as neither yeast nor green beer is a homogeneous mixture.

Samples drawn from the same fermenter over a short period will easily vary in yeast concentration with 50 percent. The yeast collected from a fermenter is varying in concentration just as much. As the multiplication is related to the flavor and as irregularities may be the first warning of upcoming fermentation problems, and indirect measurement of the multiplication was tried.

The decrease of the TNBS-protein fraction was correlated to yeast multiplication in laboratory scale trials. Even under extreme conditions a good relationship was found. Each new yeast cell could be predicted simply by the equivalent drop in TNBS-nitrogen. Even the day to day variations could be directly related to the multiplication if the first and the last day were ignored.

In full scale fermentation, the control system proved to be practical and reliable. Proposals are made to the design of the control system for yeast multiplication including practical reactions to variations in the multiplication.

Solving the Problem of High Protein Malts

A detailed look at malt analysis shows that malt used did indeed fit the intended profile. High protein malts result in high wort protein, FAN and formal nitrogen and also in more fermenting by-products, such as diacetyl. Foam testing results show that the high protein malts made beer with better foam quality. The proteinaceous material in beer is of considerable interest because it is a major constituent in both beer foam and haze.

Microbrewery Design and Performance

Microbreweries have caught the attention of the consumer and the media alike. Over the last 13 years in the United States and Canada, their market share and sophistication have increased dramatically. Currently there are over 275 operating microbreweries in North America each producing between 300 and 18,000 hectoliters per year. This presentation examines American and Canadian microbrewing equipment and production methods from the brewer's perspective. Brewhouse, cellaring and packaging equipment is discussed, including the reasons for design choices. Emphasis is placed on specific examples utilizing photographic slides. Equipment performance parameters such as brewhouse yield, energy usage and manpower requirements are outlined. Comparison is made to European microbreweries.

Simulation and Optimization of Aeration in Beer Fermentation

Wort aeration is closely related to the substrate consumption and product formation during beer fermentation. These products include sugars, amino acids, organic acids, esters and higher alcohols, therefore aeration greatly influences the taste and flavor of beer. Until now, it has not been possible to correlate the extent of wort aeration to the fermentation performance of yeast during wort fermentation quantitatively.

In this study, the dissolved oxygen concentration during wort aeration was calculated using a double film theory model for the absorption of oxygen. Next, the optimum total dissolved oxygen consumption by yeast (abbreviated as TDOC, hereafter) was estimated from the fermentation

A Process Engineering and Technological Approach to Mash Separation

We discuss a process engineering approach to the design of mash separation in brewing. The proposed procedure is based firstly on a full evaluation of the raw material and in particular biochemical analysis of mashing. It is important that the characteristics of the laboratory mash be fully representative of that to be used industrially. For this we use a given temperature profile of the mashing process which integrates the main enzymatic activities. Once the mash is prepared the determination of the filtration characteristics is to be carried out by standard filtration tests. For this we propose a batch constant pressure filtration with automatic data logging by means of an electronic balance. These results can then be used to scale up the mash separation process by classical chemical engineering methods bearing in mind the specifics of brewing.

The Acidification Power Test and the Behavior of Yeast in Brewery Fermentations

Beer quality is related to fermentation technical factors and mainly to the physiological condition of yeast. During the wort fermentation period, several reactions closely related to cytoplasmic membrane occur in yeast, among them are: nutrients uptake, metabolic by-products extrusion, respiratory activity, vicinal diketones reduction, etc. On the other hand, the incubation temperature, the pH of media, the age of the culture, the ethanol concentration and the yeast storage conditions are factors with a strong effect on the normal fermentative behavior.

The acidification power test is a simple and reliable method for the evaluation of yeast healthliness. It is based on the ability of yeasts to acidify the surroundings media when they are suspended in a glucose solution (0.1 percent), a phenomenon directly related to the physiological condition of yeast.

Information obtained with the use of the acidification power test is used to predict the fermentative behavior, tolerance to different emperatures of storage and the vicinal dikestones reduction ability of some lager yeast strains.

Influence of Wort Amino Acid Levels on Vicinal Diketone Production in Lager Fermentations

The vicinal diketones (VDKs), diacetyl and pentanedione, are secondary by-products of the biosynthetic pathway for valine and isoleucine, respectively. While much is known concerning the genetics of this pathway, little information exists describing the influence of wort amino acid levels on the production of VDKs. Computer aided design of experiments (CADE) was used to assess the impact of 10 tp 50 percent increases above normal levels of isoleucine, valine, leucine and threonine on the production of VDKs and acetoin in 15 degree P wort fermentations. Addition of isoleucine, even at 10 percent leads to enhanced production of diacetyl and acetoin, but lowered pentanedione, while valine and leucine decrease diacetyl and acetoin production.

Enhancing Expression of the Saccharomyces Diastaticus Glucoamylase Gene in Polyploid Saccharomyces Uvarum.

To satisfy purposes of stability and enzyme activity we used the ribosomal DNA, which has 100-120 copies repeated in tandem in Chromosome XII. The 2.8 kb EcoR1 fragment ribosomal DNA in S. diastaticus was isolated and inserted to both ends of target which has STAI gene and Cupl gene in YCp50CS. Then we cut both ribosomal DNA with Bg1II to make a linear DNA and got it integrated in chromosome of host, polyploid S. Uvarum OE2.

This was named S. Uvarum OE2I. When we did southern hybridization S. Uvarum OE21 total DNA with probes, we found that there were high copies of STA1 gene and no bacterial sequences inserted. ANd when we produced beer using the S.Uvarum OE2I in 8L EBC tube, fermentation profiles and flavor were adequate and the taste was palatable except the early attentuation rate of S. Uvarum OE2I was slower than that of host, S. Uvarum OE2.

As a result, a new brewing yeast which has high stability and glucoamylase activity was constructed.
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Title Annotation:technical papers for the Master Brewers Association of America conference
Publication:Modern Brewery Age
Date:Sep 10, 1990
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