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Supply Chain Lessons in Improved Process Control for Product Quality Attributes and Plant Productivity Metrics as Captured in Fishbone Diagrams

A journey in brewing science and the ASBC. It all started nearly 20 years ago with a literature review exercise seeking to identify malting and brewing process parameters that impact the production of yeast-produced beer flavor compounds. I elected then to capture pertinent information in the form of hand-drawn cause and effect diagrams — commonly referred to as "fishbone diagrams." Since that time, many more fishbones, covering a wide array of practical subjects of interest to brewers and brewing scientists, have been generated. While at times I’m not exactly sure if they are a curse or a blessing, these "bones" have sure assumed a life of their own! At last count, the number is closing in on 200 independent fishbones covering 33 subjects, with 120 of these included in this publication.

It is with sincere appreciation to employers and associates alike in the United States and global brewing communities that I donate these fishbones to ASBC for inclusion in Brewing Chemistry and Technology in the Americas. While all proprietary information has been removed to protect the interests of past employers, the hope is they still can serve as practical, educational, and actionable reference materials for anyone interested in brewing. To assist in the interpretation of these fishbones, as well as provide readers insights on the journey traveled leading to their creation, the following information precedes the actual fishbones themselves:

  • a brief description of cause and effect fishbone diagrams
  • information on the software technology used to create fishbones
  • sources of information used to populate the fishbones
  • principles followed in the creation of the fishbones
  • categories of information included in the fishbones
  • a list of acronyms used in the fishbones
  • a list of the fishbones by number and title

Cause and Effect Diagrams "101"

A cause and effect diagram is a visual way of representing the relationship between an "effect" of interest to a maltster or brewer (e.g., beer flavor stability) and observed "causes" influencing or correlating with the stated effect, e.g., time, temperature, total in package oxygen (TIPO), etc. Typically, the effect is depicted on the far right side, with causes or correlations occupying the rest, and majority, of the diagram. Causes or correlations are grouped by categories, and within each category multiple individual effects are listed. As a rule of thumb, the most frequently used categories are the "4 Ms" (machines, manpower, materials, and methods). However, there really are no limits on the naming of categories. Most frequently, I have established categories based on the process point within the supply chain (e.g., malting, brewing, fermenting, aging, finishing, packaging, shipping, etc.). Once populated, a cause and effect diagram visually resembles a fish skeleton devoid of flesh. Accordingly, fishbones are commonly (and affectionately by this author!) referred to as "fishbone diagrams."

Technology Used to Generate Fishbones

In the pre-PC world of the late 1980s (well, at least for me it still was!), I elected to capture pertinent information in the form of hand-drawn cause and effect fishbone diagrams. Use of this format was manageable when the number of fishbones was limited and the content relatively brief. As the years progressed, however, new fishbones were generated as a result of routinely using this tool in troubleshooting situations. The typical scenario was the mustering of a cross-functional team consisting of personnel from QA/R&D/QC/brewing functions, plant management, and plant operators triggered by a loss in process control for a particular beer quality or productivity parameter. Fishbones would subsequently be used to capture the results of preliminary literature searches, brainstorming sessions with brewery operators, and ultimately the lessons resulting from the successful resolution of the root cause(s).

Examples of these scenarios include:
1. Extremely wet weather in the early 1990s led to problems of beer gushing and mycotoxins in malt supplies. Tackling these issues was the genesis for fishbone series XXV and XXVIII: "Process Control to Prevent Gushing in Beer" and "Process Control for Mycotoxins in Malting," respectively.
2. Lessons captured as a result of troubleshooting phenolic off-flavors observed during brewery-specific brand qualification trials led to the creation of fishbone series XXII, "Process Control to Prevent Medicinal, Phenolic, Astringent, and Grainy Off-Flavors in Beer."

As a result of the rapid growth in the shear number of fishbones, upkeep of these reference materials by hand became impossible! It was time for "them bones" to join the digital era, a task for which I was woefully unprepared.

Fortunately, over the past 15 years, two key people have enabled the conversion of the fishbones to an electronic format. The first was Lauren Stenroos of The Stroh Brewery Company, who in the early 1990s converted these hand-drawn fishbones into individual files using the software program Harvard Graphics. I am deeply indebted to Lauren for providing a technological solution enabling the electronic maintenance of the fishbones. Given my widely recognized and deservedly earned reputation for having illegible writing, Lauren’s ability to patiently work through my handwriting when updating or creating new fishbones is frankly nothing short of a miracle! Thank you, Lauren!

However, upon the demise of The Stroh Brewery Company in April 1999, I found myself "clueless in Golden" vis-à-vis being able to digitally maintain the fishbones. I will never forget the moment of panic when the CD containing copies of the fishbones could not be read on either my home or work PC! Fortunately, along came John Kelley of U.S. Quality at Coors Brewing Company. Working with the Harvard Graphics CD, he used the Visio software program to convert each fishbone into the format used today. Even more impressively, John acted as my first digital mentor, teaching this dinosaur how to apply Visio in not only updating fishbones, but also in the independent creation of new ones! Gone then in 1999 was the need to have handwritten drafts updated by another person; the master had trained the grasshopper how to fish! For this liberating mentoring in PC technology, I am forever grateful to John. Thank you, John!

Sources Used to Populate Fishbones

The sources of data (i.e., "causes or correlations") used to populate the first generation of fishbones on yeast-produced flavor compounds (i.e., "effects") exclusively originated from published brewing literature from the pre-1989 period. While publications have continued to be the key sources of input to the fishbones, the scope has since expanded to include the following:

  • unpublished personal experiences
  • professional society meetings (e.g., ASBC, MBAA, EBC, etc.)
  • conversations with maltsters, suppliers, brewers, and brewing scientists
  • lectures, workshops, and seminars
  • vendor literature

Given the wide array of published and unpublished sources that have contributed to the content of the fishbones over the years, I would like to walk the readers through the "fishbone principles" followed in their creation. I hope that an appreciation of these principles will assist in better understanding how to utilize these reference materials in each reader’s brewery.


Where to begin? Certainly, I owe a debt of gratitude to my parents (Geraldine and Paul Casey) for instilling in me a work ethic and value system that have both served me well in this journey. Likewise, I thank my long-deceased grandmother for her mentoring that "there is no such word as can’t"—never did I appreciate as a child the importance of taking this attitude in life! Appreciation is also extended to my employers of the past 17 years for providing me the privilege of a career in the brewing industry, namely: Molson Canada (1979–1984, Ph.D. thesis support); Carling Brewery (summer, 1979); Carlsberg Breweries (1984–1986, postdoctoral fellowship); Anheuser-Busch, Inc., (1987–1991), Stroh Brewery Company (1992–1999), and Coors Brewing Company (1999–present).

Additionally, I would like to recognize key mentors in my career, including Professor Mike Ingledew of the University of Saskatchewan (for applied scientific thinking), Mogens Pedersen of Carlsberg Brewery in Copenhagen (for introducing me to the technique of chromosome fingerprinting), John Grigsby of Anheuser-Busch, Inc. (for making the understanding of gauge R&R at a "gut level" possible—and for his passionate support over the years for the ASBC Technical Committee), Joe Hertrich of The Stroh Brewery Company (for illustrating the interaction of brewing materials, especially malt, and brewing practices to process control for product quality and beer filterability), Steve Anderson of The Stroh Brewery Company (for teaching me that whenever troubleshooting losses of process control for any parameter, both process and gauge sources of variability must be considered—and to always conduct full process surveys), and Dennis Puffer of The Coors Brewery Company (for broad exposure and involvement in quality, productivity, service, and financial metrics across the entire supply chain in a modern brewery—and how enabling functions help drive these).

Last, but most important, I thank my family (Lynn, Troy, and Chris) for putting up with all the moves over the years! Since 1984, we have established homes on two continents, three countries, one province, and four states. Through it all, they have been the raison d’etre and incredibly supportive. I am a lucky and blessed man.

Gregory Paul Casey, Developer of the ASBC Fishbone References

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