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56 Pharmaceutical Technology BIOLOGICS AND STERILE DRUG MANUFACTURING 2018 P h a r mTe c h . c o m Quality the coffee be sourced from vari- ous growing regions or should it be single-sourced? What level of roast should be used: light, me- dium, dark? How will the roast- ing be controlled? How will the beans be ground, and to what degree? Should there be a max- i mu m t i me a l lowed bet ween grinding and brewing? Will tap water be used, or should some form of processed or f iltered water be considered? These de- cisions impact the process and must be caref ully considered. Some process variables are more critical than others. Even in this simple example, there are many fac- tors to consider, and biopharmaceutical process- ing is much more complex. An Ishikawa (fishbone) diagram is a helpful tool for visualizing processes and process inputs. Figure 2 is an example applied to coffee brewing. Once the decisions have been made with respect to the coffee and water, supported by evidence from the tasting trials, the brewing process can be considered. Data from how the coffee used in the tasting studies was prepared serve as the basis for developing and validating the brewing process. Wherever possible, quantitative values should be established and documented so they can be used for process execution and further evaluation. Equipment make, type, model, and serial number should be documented. The brewing process must be carefully assessed before validation can begin. What brewing pro- cess will be used—percolation, drip, vacuum, or French press? Assuming the coffee type and grind have been determined, what brewing ratio, coffee- to-water, will be used? How long will the brewing cycle be? How will it be timed? What water tem- perature will be used, and when and how will that temperature be measured and controlled? What, if any, type of filter is employed? How will the brew- ing equipment be cleaned and when? Will deter- gents be used? If so, what duration and type of rinsing will be used to remove detergent residues? The coffee brewed for the tasting studies will have been prepared in some controlled manner using identifiable coffee type, roast, and grind, and processed in equipment that will serve as the basis for selecting equipment for the commercial brewing process. Once the choice of equipment has been finalized, the equipment must be qualified with respect to its operational parameters. What brew settings are available? Which ones have a critical impact on the taste of the brewed coffee? How reproducible are the settings, and how accu- Figure 2: Fishbone diagram of a simplified coffee-brewing process. A SIMPLIFIED COFFEE-BREWING PROCESS COFFEE PROCESSING PEOPLE WATER GOOD-TASTING COFFEE Type Attitude Training Knowledge Thoroughness Tap, Filtered, Processed? Temperature Grind Roast Coffee to Water Ratio Brew and Holding Time Equipment Type