George Philliskirk
CONTENTS
21.2 Quality Management Systems
21.2.2 Hazard Analysis Critical Control Point (HACCP)
21.4.1 Repeatability and Reproducibility
21.4.4 Microbiological Methods
21.5 Customer and Consumer Feedback
21.7 Beer Quality at the Point of Sale
21.1 INTRODUCTION
We can be sure that in most chapters in this handbook the word quality will feature prominently at some stage, although the context may appear to be different in many cases. So what, exactly, do we mean by “quality”? Learned texts on the subject, of which there are many, will quote a range of definitions with varying degrees of sophistication and elaboration. My favorite definition (because it is the simplest) is that, “Quality is meeting the customer requirements.” This chapter will focus on meeting the requirements of the customer (or consumer) for beer—be it dispensed in a glass or delivered via a can or bottle in a variety of packaging formats. The emphasis will be on the practical issues related to managing the quality of beer throughout the supply chain—from the purchase of raw materials to presenting the finished product to the customer. As mentioned earlier, there are several excellent books that will give the reader detailed insight into the many facets of quality management. (Total Quality Management by Oakland1 is particularly recommended.) However, the scope of this chapter and the nature of this handbook are such that the focus of the content will be on what we actually do in a brewery and packaging hall to deliver quality through the supply chain. Although the requirements of quality management will vary according to the size and scale of the brewing operation—a one-person microbrewery will have different challenges than a multinational brewery. Nevertheless, the guiding principles and practices set out in this chapter find application across all brewing operations. For so-called “microbrewers,” gone are the days when the designation “real ale” or “craft beer” was sufficient to sell a beer. Beer drinkers are far more discerning than 20 years ago, and consistent quality of taste and appearance is as essential to the craft brewer as it is to the international brewer.
Achieving a consistent quality does not happen by chance or because we just talk about it. To achieve quality we must work at it by understanding our processes—the work we do every day—and actually improving them. In other words, quality needs to be managed effectively at all levels of an organization to meet the requirements of the customer. The customer in this context is not only the end user but also the recipient of a process, product, or service throughout the supply chain. This chapter will attempt to guide the reader through managing quality in the beer supply chain.
21.2 QUALITY MANAGEMENT SYSTEMS
A quality management system (QMS) refers to the activities that are carried out within an organization to satisfy the quality-related expectations of its customers. The scope of a QMS may vary considerably from an unwritten, word-of-mouth set of procedures operated in a very small microbrewery to a sophisticated, documented series of manuals, procedures, and interactions. Although the effective management of food safety responsibilities through the Food Safety System Certification (FSSC) 22000 has become a priority requirement in meeting customer needs, at the core of most QMSs is the ISO 9000 Quality Systems Standard.
21.2.1 ISO 9000
ISO is recognized as the short name for the International Organization of Standardization, an international agency consisting of more than 160 member countries.
ISO 9000 addresses various aspects of quality management and includes some of the widely applied ISO standards. The standards provide guidance and tools for companies and organizations who want to ensure that their products and services consistently meet their customers’ requirements and that quality is consistently improved. Within the family of ISO 9000, four key standards have been identified as the key components of a QMS:
All ISO standards are reviewed at least every five years to ensure they are current and relevant. For example, the latest revision, ISO 9001:2015, places increased emphasis on risk-based thinking and compatibility with other international standards such as the environmental standard ISO 14001.
The adoption and implementation of ISO standards may be seen to be unnecessarily bureaucratic and resource consuming. However, organizations benefit because the use of ISO 9000 serves as a basis to:
However, complying with the ISO 9001 standard does not indicate that every product or service meets the customer’s requirements, only that the quality system in use is capable of meeting them.
Although ISO 9001 is usually at the core of a brewery’s QMS, whether it is registered or not, most breweries need to comply with other specific requirements either from regulatory bodies or customers. The legal requirements imposed by government (in the United Kingdom, from both the UK government and the European Union [EU]) in the area of food safety have increased significantly over the last two decades with the introduction of FSSC 22000. This legislation has reflected increasing customer awareness of aspects of quality and safely relating to food and drink, from raw materials through production and processing up to and including packaging and point of sale.
21.2.2 Hazard Analysis Critical Control Point (HACCP)
Brewers have addressed these requirements primarily through the application of hazard analysis critical control point (HACCP) methods. Since 2006, food and beverage manufacturers in the EU have a legal obligation to operate an effective HACCP system, and in the United States, the Food Safety Modernization Act (2011) also enforces HACCP principles.
The key elements of an HACCP system2, 3 can be listed as follows:
In HACCP terms, hazards are defined as any microbiological, physical, or chemical contaminant that may potentially gain access to the food or drink product and cause harm to the consumer. Although hazards clearly relate to safety, in the brewing context, any failure to ensure safety is also a failure in quality; the application of HACCP is therefore seen as an integral part of a QMS.
When carrying out an HACCP program, the principles of HACCP are implemented in a series of stages outlined in Figure 21.1. A detailed review of the application of HACCP in brewing is beyond the scope of this chapter, but several key points are worth emphasizing:
Figure 21.1 Stages of HACCP.
The World Health Organization (WHO) recommends that CCPs should be determined using the HACCP Decision Tree (see Figure 21.2).
Figure 21.2 HACCP decision tree.
Before embarking on an HACCP implementation program, a number of issues need to be addressed and listed as requirements (HACCP prerequisites). Development of the HACCP plan in a brewery must refer to this list as the prerequisite program (PRP). The PRP list would include the following:
Although the aforementioned issues may seem formidable, most breweries will already have in place policies and procedures that cover most if not all of these requirements.
Specific threats to product quality through deliberate contamination or adulteration, particularly of raw materials, has led to the development of the principles of threat assessment and critical control point (TACCP). TACCP has now become an essential requirement of food safety standards.4, 5
21.2.3 Customer Requirements
It is not uncommon for some customers to impose their own specific requirements for quality and/or safety inspections. In the United Kingdom, until about 2000, each major retail customer (particularly the larger supermarket groups) would audit a supplying brewery on a regular basis. This practice was time-consuming and expensive for both parties involved and inevitably resulted in much unnecessary duplication of effort on behalf of the quality assurance (QA) department of the brewery. In the United Kingdom, and elsewhere in Europe, the major retail groups in each country decided to establish a set of common standards against which suppliers would be audited. This abolished the need for auditing by the individual retailers and instead required suppliers to meet the standards demanded by third-party auditing of accredited bodies. In the United Kingdom, this became known as “BRC Accreditation.” BRC is an abbreviation for the British Retail Consortium, a trade body in the United Kingdom. Subsequently, this became the BRC Global Standard for Food Safety (BRC GSFS) to bring it in line with international standards.
Under the terms of the United Kingdom’s Food Safety Act (1990), retailers have an obligation to take all “reasonable precautions” and exercise “due diligence” in the avoidance of failure, whether in the development, manufacture, distribution, advertising, or sale of food products to the consumer. That obligation in the context of retailer-branded products includes the verification of technical performance of food (or beer) production sites. To address this obligation, the BRC developed the Global Standard (currently, Issue 7) for those companies supplying retailer-branded food products.
The standard requires:
There are a number of benefits arising from the introduction of the BRC Global Standard:
Internationally, the Global Food Safety Initiative (GFSI) was established in 2000 to standardize international safety standards. Additionally, in 2005, ISO introduced a new food safety standard called ISO 22000:2005 to improve international standardization. This was subsequently embraced within the FSSC 22000 requirement.
Clearly, with the continuing growth of truly global brewing companies where movement of beer across international borders is an essential part of optimizing the supply chain, it is important that common international standards are established and recognized to avoid unnecessary (and costly) duplication and bureaucracy.
21.2.4 Systems Integration
The ISO 9001:2015, HACCP, BRC Global Standard, and FSSC 22000 systems exist as stand-alone requirements despite the fact that all are very closely interrelated. Indeed, outside these quality and safety requirements, most breweries are committed to a whole range of standards covering a range of activities deemed necessary to meet legislative, consumer, environmental, and good management practices. For example, some breweries have the requirement to maintain the following standards and guidelines.
There is clearly considerable scope for duplication within these various standards, leading to inefficiencies in utilizing management time in maintaining these standards and in confusion for plant operators when confronted by a whole range of procedures and work instructions allocated to the different standards. Many breweries have addressed these problems by developing an integrated management system (IMS). The key elements of the approach to integration are as follows:
An IMS is structured along the lines of the ISO standards’ format with three sections: an operations manual, integrated procedures, and integrated training/operating methods.
The operations manual will encompass:
The integrated procedures will cover:
The integrated training/operating methods will ensure:
The structure of an IMS is shown in Figure 21.3. Although the scope of the IMS embraces various operational activities, the IMS is often referred to as “the operational system,” although the structures and procedures defined under a QMS serve as a template for the effective management of the operational activities in a brewery. This systems integration enables ownership and involvement by the teams operating in a particular area of the brewery, allowing easy access for operators through local PCs, minimizing paper proliferation and facilitating operator training. For example, auditing a brewhouse area would cover the full range of activities within that area rather than a specific focus on quality, environmental, or safety procedures.
Figure 21.3 Structure of an integrated management system.
The QMS establishes the framework on which the process of meeting the requirements of the customer is built. A process is the transformation of a set of inputs that can include: actions, methods, and operations into desired outputs in the form of the products, information, or services. Clearly, to produce an output that meets the requirements of the customer, it is necessary to define, monitor, and control the inputs to the process. Achieving control of the inputs should result in the desired outputs without the recourse of detailed monitoring and inspection of these outputs. This is the goal of modern quality control operations in brewing. We will now look at how this can be achieved.
21.3 MATERIALS CONTROL
21.3.1 Supplier Relationships
The materials used in brewing and packaging beer are diverse, from the basic brewing materials of malt, hops, yeast, and water through to the chemicals used in plant cleaning, process gases, plant items, packaging, and dispense equipment at the bar. It is essential that, in all materials or services purchased, the supplier is capable of meeting the requirements demanded by the user. These requirements do not merely relate to conformance of specification or price. Factors such as on-time deliveries (with the correct quantity at each time), rapid response to program changes, technical troubleshooting, and product improvement are also important considerations in assessing the worth of a supplier. As brewers increasingly seek to reduce inventories of material stocks, the onus on the supplier increases. In many instances, the supplier (vendor) is given sole responsibility for the delivery of stockholding materials (malt, bottles, etc.) to the brewhouse or bottling line in response to production demands. This process, often referred to as vendor-managed inventory (VMI), demands close liaison between supplier and brewer, particularly among planning functions. The development of information technology (IT) systems greatly facilitates this process, particularly in those systems (e.g., SAP - Systems, Applications and Products in data processing) with intercompany communication links sharing common IT platforms. However, these developments demand a close partnership between supplier and customer, with particular emphasis on the customer enjoying complete confidence in the supplier’s ability to deliver a product to specification and on time. This confidence reduces or eliminates the need for inspection of materials entering the brewery or packaging hall. This close partnership has become increasingly important in the effective quality management of materials supply.
Brewing companies are recognizing that long-term strategic alliances with suppliers are the best way of optimizing value in sourcing materials, with single-sourcing arrangements increasingly prevalent. Gone are the days when the brewer sourced his malt supply from different maltsters to ensure he/she could even out differences in quality!
Establishing single-sourcing contracts demands considerable research on behalf of both supplier and user. The user must ensure that all the parties involved in using the product or service are fully engaged in agreeing to the contract terms and drawing up the product and service specifications. This may involve purchasing, technical/quality, production, marketing, IT, and finance functions. Clarity of communication and understanding is essential if the needs of the user are to be accurately transmitted to the supplier. From the technical/quality perspective, the involvement will focus on devising the technical specification and auditing the supplier.
21.3.2 Specifications
Specifications must be realistic, in that they must reflect the actual requirements of the user and not a theoretical wish list of items that do not relate to the actual use of the product supplied. There is a temptation in drawing up specifications to include specific requirements that are not really required or to include tolerances on certain parameters that are either outside the process capability of the supplier or the analytical capability of the measurement (see later sections on process control and analysis) or both.
The simpler the specification, the more likely it is that the supplier can deliver the product consistently within specification. More complex specifications usually result in added cost and more disagreements between supplier and user. It is important for the brewer to involve suppliers in the drafting of specifications. The supplier must be aware of the constraints on the use of the material by the customer and work with the customer to minimize any possibility of downstream problems caused by material not being fit for purpose. Regular reviews of material performance are essential between supplier and customer. These reviews not only focus on the results of the analysis of incoming materials and delivery conformance but also on the downstream process performance influenced by the material. For example, in reviewing malt performance with a malt supplier, the brewery manager will look at brewhouse throughput rates, runoff performance, wort-free-amino nitrogen levels, fermentation, and beer filtration performance. The advantage of a single-sourcing agreement is that, in the case of malt performance, it leaves no room for the maltster to blame another supplier!
It is unusual for breweries to routinely monitor the quality of incoming materials. There is considerable cost to the brewery in both sampling and analysis and, given a close relationship with the supplier, the customer should have confidence in the ability of the supplier to deliver in specification and on time. Occasionally, a supplier may notify the customer of a parameter that may be slightly outside specification. The customer may choose to reject this delivery or accept the delivery as a concession. However, these should be rare occurrences and certainly recorded for review at the supplier meetings. A typical lager malt specification is shown in Table 21.1 and is divided into three sections. Section 1, Quality Parameters, looks at the specification target values with upper and lower tolerances and the approved analytical methods. Section 2, Production and General Conditions, focuses on issues relating to process control and monitoring of potential hazardous substances, while Section 3, Technical Transport Requirements, looks mainly at the conditions for hygienic transport.
Table 21.1 A Typical Lager Malt Specification
Although the specification is important for both supplier and purchasers in that it defines those attributes of the material that are relevant to the purchaser and capable of definitions, it is of limited value in establishing confidence in a new supplier, particularly a new supplier with no proven track record of supply. A key element in establishing confidence is through the process of auditing.
21.3.3 Auditing
Auditing is an essential part of maintaining and developing a QMS and in evaluating the worth of suppliers. Audits are mandatory requirements for many certification schemes such as ISO 9000 and are a way of obtaining objective feedback on how effective the quality system is working: what’s working well, what can be improved, and what is not fulfilling the planned levels of performance.
Any audit must be measured against the requirements of the system. In the case of ISO 9000, the clauses of the standard define the requirements of the system, and regular structured internal and external audits are required to test compliance to the standard.
The auditing of a supplier is usually on a fundamentally different basis. Instead of a formal audit of the QMS, the auditor will usually focus on those elements of the supplier’s activities that relate directly to the quality of the product or service supplied. As mentioned earlier, compliance with the ISO 9000 standard does not necessarily guarantee that the product supplied will meet the requirements of the customer (although it is a good starting point!). The requirements of a supplier audit are usually defined by the purchaser, and the scope and frequency of the audits will normally be based on the risk elements to the purchaser. For a new supplier, the initial audit is very rigorous, involving a thorough examination of the supplier’s processes, the QMS in general, and the state of housekeeping and hygiene. The result of the audit will usually be either:
This first audit, or approval audit, should normally be carried out ahead of the first purchase from the specific plant. A number of stages are usually involved in preparing for this first audit:
At the audit, the agreed agenda is followed. The audit tour of the plant and laboratories is the most important part of the audit, and time is allocated accordingly. The auditors will meet after the tour, and the findings from the audit will be discussed, including the necessary action points. On the basis of the findings, it is judged whether the plant can be approved, approved with comments, or not approved. The lead auditor will present the main findings and conclusions at the closing meeting with the suppliers. All required action points must be addressed and agreed upon with the supplier.
Audit criteria for the assessment of the audit findings need to be defined, and typically the findings will fall into three categories—“satisfactory,” “not quite satisfactory,” and “not satisfactory.”
If any of the activities is judged to be “not satisfactory,” the plant is “not approved.” If any of the areas (process, QMS, or housekeeping/hygiene) are deemed “not quite satisfactory,” the plant is “approved with comments,” and the not quite satisfactory issues need to be addressed. Plants that are “approved” without any comments may have some minor issues raised.
Any action points arising from the audit should be addressed by the supplier and followed up by the auditors within a reasonable timescale. Once a new supplier or plant is approved, it is normal initially to submit the supplier to higher levels of surveillance on incoming materials and product performance than for well-established suppliers with a proven track record. It is again important to stress the value of regular review meetings and customer feedback to the supplier. Thereafter, suppliers will be subjected to routine audits on an annual or biannual basis, depending on the importance of the material purchased and the degree of risk of failure. The routine audit will follow the same format as the approval audit, excepting that the audit team will often be fewer in number, and the areas covered will be less extensive.
The results of the audits will be disseminated to all interested parties. In larger, often multinational, brewing companies with international sourcing of materials and services, the data from these audits are often collated and the database shared among breweries.
In summary, auditing of suppliers is a key aspect of establishing confidence in the supplier and minimizing the need for inspection at the point of supply or use. Additionally, feedback through the audit process can help the suppliers improve their own performance—although auditing can sometimes be painful to the supplier, it is also a potential source of free consultancy (for both parties!).
21.3.4 Raw Materials
The basic raw materials used in brewing are malted barley, water, hops, and yeast. Additional sources of fermentable extract (adjuncts) may be used to augment or replace the malted barley, depending on beer style, tradition, or economics. The malted barley and hops are, in particular, subject to a biological variability created by changes to the growing season and the ongoing development of new varieties designed to deliver improved agronomic performance to the grower while ensuring that the requirements of the processor and end user (brewer) are met. This biological variability is an important factor to be considered in drafting specifications, particularly for malted barley. Despite the best endeavors of maltsters and brewers, different malt batches, which conform to the agreed specification, may perform differently in the brewhouse. New varieties and new season barleys should be assessed carefully before introduction, and both the malting process and brewhouse procedures may need to be manipulated to deliver a consistent output. It is important that maltster and brewer work closely together to minimize the impact of any changes, and a review of the malt specifications is needed from time to time to ensure that it is relevant to the brewer’s needs.
Seasonal and varietal changes in hops also need to be taken into account, particularly where the contribution of hops to the aroma characteristics of a beer is considered important. Measurements of the alpha-acid content of hops from harvesting through storage (particularly in the presence of air) show an almost linear decline in alpha levels but also increases in the so called hard resins, which can lead to the development of unacceptable “cheesy” aromas. The hop storage index (HSI) is a useful measurement of these changes. Processed hops, in which the alpha acids are isomerized and extracted or the essential oils extracted, tend to enjoy greater stability with storage time. Although specifications for hop products used for bittering purposes can be reasonably well defined in terms of variety, source, and alpha acid content, assessing the quality of hops used in late-hopping or dry-hopping of cask beers is more problematical in the absence of sound analytical measurements. Again, close liaison between hop supplier and brewer is demanded, with auditing of processing plants and hop stores needed to monitor the changes in quality.
The presence of unauthorized pesticides and herbicides possibly used in the growing of hops should be monitored carefully, together with unacceptably high levels of approved substances. Although the brewer will define these limitations in the specification, and the hop supplier will issue the appropriate certificate of analysis confirming conformance at the time of delivery, it is incumbent on the brewer to periodically send samples of the delivered hops or hop products to what is usually a specialist laboratory for independent verification. These checks would normally form part of an HACCP program.
Water comprises about 94% of the content of beer and can exert a significant influence on the quality of beer (see Chapter 4). In addition to the effects of brewing liquor on brewing performance and flavor, the quality of the water is a significant contributor to the safety and wholesomeness of beer. Water quality is usually carefully regulated through national legislative controls, and the water used directly in brewing (mashing, sparging, dilution) should conform to these regulations. Where breweries purchase water, from either municipal supplies or utilities companies, certificates of analysis are provided on a regular basis to confirm compliance to the agreed standards. Where breweries utilize their own sources of water (often boreholes) the quality of the water must be monitored rigorously and, if necessary, treated to attain the required standards. There are potentially four major classes of contamination found in water6: microbiological, inorganic, trace organic substances, and pesticides/agrochemicals. The implications of contamination by these four groups of materials are discussed in detail in Chapters 4 and 19.
An effective yeast management system is a major requirement for brewing beer of consistently high quality. Chapter 8 covers this topic comprehensively, but it is worth emphasizing the importance of a structured yeast management program that accommodates the following: strain maintenance, propagation techniques, contamination checks, viability and vitality, DNA fingerprinting techniques (if available), and procedures for harvesting, storing, and re-pitching the yeast in process. The avoidance of stress factors (high gravity fermentations, shear forces, high storage temperatures, nutrient deficiencies, high generation numbers) needs to be carefully managed.
21.3.5 Other Materials
Although malt, hops, water, and yeast can be described as the basic raw materials of brewing, control of which is essential to delivering beer of a suitable quality, many other materials need to be purchased and controlled applying the same principles outlined for malt and hops. Detergents, process gases, process aids, additives, packaging materials, and so on must be specified, suppliers audited and approved, and performance monitored in the brewery and the packaging hall. Packaging materials (bottles, cans, crates, kegs, cartons etc.) constitute a significant cost element in beer and impact not only production efficiencies but also final presentation to the customer or consumer. The need for well-defined technical specifications, agreed upon with the supplier, is essential.
21.4 ANALYTICAL CONTROL
The emphasis on the role of analytical control has shifted significantly over the past 40 years or so in brewing operations. Traditionally, brewers employed large numbers of chemists and microbiologists to sample and measure at every stage of the brewing process, from raw materials at intake through to inspection of finished product in keg, bottle, or can. These inspections were borne out of a lack of confidence—in the supplier to deliver materials to specification and in the ability of the process to control the operation. Despite these inspections, which spawned large QC departments (at great expense), the costs of internal failure (rework, disposal) and external failure (returns, customer complaints, lost business) were high.
The development of QMSs with an increasing emphasis on controlling the inputs to a process rather than inspecting the outputs, has reduced considerably the costs of both the inspection (QC departments) and the internal and external failures. However, there is still a need for measurements at various stages of the brewing and packaging processes to confirm that the process is still in control. Ideally, these measurements or analyses should be made in-line, with suitable feedback control for process adjustment, or on-line where the operator can directly intervene to adjust the process if necessary. For more sophisticated measurements or nonroutine checks, a central laboratory function needs to be available. This can be either an in-house facility or, increasingly, outsourced to an accredited external laboratory service provider. Confidence in the accuracy and reliability of the measurements, be they at the time or in a central laboratory, is essential. Rigorous equipment calibration procedures need to be in place (a key element in the ISO 9000 standard) and supported by regular monitoring among reference laboratories. This regular monitoring and critical appreciation of laboratory performance enables a realistic assessment of marginal results to be made, and the source of variation can then be ascertained—process error, sampling error, or laboratory error. Obtaining a representative sample needs careful thought and consideration, particularly for large bulk solids such as barley, malt, and hops. For example, when sampling a wagon containing malt or barley, the number of sampling points recommended can vary depending on the size of the wagon.
Sampling of liquids (beer) is generally much easier, but factors such as carbonation, layering, and the position of the sample point need to be considered. Laboratory errors can arise from inherent errors in the methods, equipment, and personnel conducting the test. The methods used should be both accurate and precise, where accuracy is defined as the closeness to a true or conventionally accepted value and precision describes the amount of variation in a method. Classically, this relationship between accuracy and precision is best demonstrated by considering a number of arrows aimed at a target. The degree of scatter of the arrows in the target is referred to as precision, while their overall closeness to the center is known as accuracy. Figure 21.4 illustrates this point.
Figure 21.4 Accuracy and precision. (a) Accurate and precise, (b) precise but inaccurate, (c) accurate but imprecise, (d) inaccurate and imprecise.
Any analytical method should be capable of giving an accurate measure of the true value every time a measurement is made. Checks on the accuracy and precision of analytical methods are made by comparing the results of the analysis of a sample both within and among laboratories to establish the repeatability (r95) and reproducibility (R95) of the method.
21.4.1 Repeatability and Reproducibility
Checks within the same laboratory (i.e., the repeated analysis by the same analyst) on the same equipment, on the same sample at the same time, give a measure of the repeatability of that method. The r95 value relates to a range of results that fall within the stated range 95% of the time (i.e., 19 out of 20 analyses should lie within this range).
Reproducibility (R95) relates to checks among laboratories (i.e., the repeated analysis of the same sample by different analysts using different equipment, at different times) gives a measure of the reproducibility of that method. Again, the 95% rule applies.
Inevitably, the values of R95 will always exceed those of r95. For example, mean precision values for bitterness measurements (or bittering units, BUs) in a major UK brewing company were determined by 16 laboratories using 33 sample pairs over a three-year period. Within a range of bitterness values from 18 to 32 BU, r95 was 1.0 and R95 was 4.1. Knowledge of the R95 values of an analyte is particularly important in establishing specification limits. The specification must take into account this potential interlaboratory variation as well as sampling errors and the process capability (explained later in this chapter) of the supplier.
21.4.2 Collaborative Trials
Collaborative trials between two or more laboratories are frequently held to check on the reliability of methods among different laboratories and to identify any problem area that can be resolved by further development. The protocols for these trials are established as an international standard (ISO 5725), and the guidelines are incorporated into the recommended methods for brewing analysis. Many brewing companies participate in collaborative schemes. One of the major open schemes is run jointly from the United Kingdom by Campden BRI and the Laboratory of the Government Chemist (LGC). This is known as the brewing analytes proficiency scheme (BAPS), and participants include breweries from around the world. (Some malt suppliers use a similar system known as the malting analytes proficiency scheme, or MAPS.) Samples of a single beer are dispatched every four weeks to the participants and a range of analytes are covered, all on an optional basis. These include:
Results from each “round” of samples are collated and analyzed statistically, and each participant is given a coded number to assess their performance against the group as a whole. Breweries are often obliged to notify their customers of their “BAPs number” to enable the customer to check on the analytical capability of the supplier. Confidence in the supplier established through this scheme will often enable the customer to minimize or obviate totally any analysis on incoming product. Results from BAPS and MAPS schemes are often used by customers as key performance indicators (KPIs) in supplier reviews.
21.4.3 Analytical Methods
It is beyond the scope of this chapter to detail all the methods available for the analysis of raw materials, beer-in-process, coproducts, finished beer, and packaging used in brewing. Brewers have been fortunate in the availability of methods used in brewing, with methods from:
However, with the growth of major international brewers over the past 20 years, represented in areas of the world traditionally using “local” methods, there is clearly a requirement to develop a single international methodology for brewing analysis. The IoB Methods of Analysis and EBC methods have been integrated within EBC Analytica, developing a single set of methods, which hopefully will ultimately embrace ASBC and MEBAK methods.
Certain beer quality parameters are common to almost all breweries and are listed as follows:
(Microbiological and flavor evaluation checks are considered in the following.)
The extent to which these basic quality parameters and other checks are employed in the brewing process will depend on the availability of resources (equipment, trained staff), the confidence in the materials supplied, and in the control of the process. One suggested brewing process analysis program is shown in Table 21.2. The frequency of sampling and testing will vary, depending on the need for immediate, in-process corrective action or as an indicator of trends. For example, of the parameters listed in Table 21.2, some may need checking on every batch (alcohol, color, bitterness, carbon dioxide, dissolved oxygen, pH), whereas others may require less frequent (often weekly or monthly) checks (free amino-nitrogen, volatiles, malt extract).
Table 21.2 A Suggested Brewing Process Analysis Program
Character |
Materials |
Wort |
Fermentation |
Maturation |
Bright Beer |
|---|---|---|---|---|---|
Alcohol |
No |
No |
Yes |
Yes |
Yes |
Original gravity |
(Malt, extract) |
Yes |
Yes |
(Possible) |
(Possible) |
Present gravity |
(Malt, extract) |
Yes |
Yes |
(Possible) |
(Possible) |
Color |
Yes |
Yes |
Yes |
Yes |
Yes |
Bitterness |
(Hops) |
(Possible) |
(Possible) |
Yes |
Yes |
Haze/clarity |
(Water) |
(Possible) |
No |
No |
Yes |
pH |
(Water) |
Yes |
Yes |
Yes |
Yes |
Head retention |
No |
No |
(Possible) |
Yes |
Yes |
CO2 |
No |
No |
No |
No |
Yes |
Dissolved oxygen |
No |
(Cold wort) |
No |
Yes |
Yes |
TSN/FAN |
Malt |
Yes |
No |
No |
No |
Attenuation limit |
No |
Yes |
Yes |
No |
No |
Yeast count |
No |
No |
Yes |
(Possible) |
No |
Microbiology |
(Water) |
(Cold wort) |
Yes |
Yes |
Yes |
Taste |
Yes |
(Possible) |
Yes |
Yes |
Yes |
Volatiles |
No |
No |
Yes |
Yes |
(Possible) |
Diacetyl |
No |
No |
Yes |
(Possible) |
(Possible) |
Source: Adapted from O’ Rourke, T., Brewers’ Guardian, 129, 21–23, 2000.
For microbrewers with limited resources of manpower and equipment, analysis can be a problem7. Brewers must decide what is essential and what is desirable. Essential analyses in most countries relate to contents (volume) and alcohol content. Declarations of allergens are required in the EU, including sulfur dioxide levels. In the United Kingdom, the Society of Independent Brewers (SIBA), which has more than 800 members, requires its members to follow its code of practice detailed in its manual of good practice. Regular checks on OG, PG, or apparent gravity (AG); color; bitterness; and pH are advised to ensure conformity to specification. Fortunately, all of these (except possibly bitterness) can be conducted in the brewery with relatively basic and inexpensive equipment. More complex and infrequent analytical checks (e.g., heavy metals, mycotoxins, pesticides, nitroso compounds) require the services of an external laboratory.
Validation of quality and traceability is often demanded by purchasers of beer, particularly supermarkets. Schemes such as the United Kingdom’s Safe and Local Supplier Approval (SALSA) are options for microbrewers to offer an accredited quality assurance scheme.7
21.4.4 Microbiological Methods
A detailed account of the microorganisms of relevance to brewing is given in Chapter 17. Brewers are fortunate in that beer provides a hostile environment for the growth or survival of potentially pathogenic organisms. However, microbial contamination of beer, or at any stage of the brewing and packaging processes, can have serious consequences for beer quality and cost.
The raw materials used in brewing (malt, cereals, sugars, hops, and water) are potential sources of microbes, although they are usually only relevant through to the stage of wort boiling, which effectively sterilizes the wort. However, the presence of some fungal contaminants on malt and some cereals, notably Fusarium species, can lead to the development of “gushing” in finished beer and the formation of mycotoxins, compounds considered to be potentially carcinogenic. Although some mycotoxins can survive the brewing process, the concentrations are greatly reduced. “Gushing” tests on malt are available and provide a reasonable indicator of potential problems. It is usual for malt specifications to include a reference to this test (Table 21.1).
Table 21.3 summarizes the possible occurrence of microbial spoilage organisms at different stages of the brewing process and their possible consequences.
Table 21.3 Microbial Spoilage Organisms in the Brewing Process
Stage |
Organisms Found |
Possible Effects |
|---|---|---|
Mashing |
Heat-tolerant lactic acid bacteria |
ATNC development |
Cooled wort |
Obesumbacterium proteus, Enterobacteria |
Off-flavors (“parsnips”), ATNC |
Pitching yeast |
Wild yeasts, O. proteus, Lactobacillus, Pediococcus, acetic acid bacteria |
Off-flavors, diacetyl, abnormal fermentations |
Fermentation |
Wild yeasts, Lactobacillus, Pediococcus |
Off-flavors, diacetyl, abnormal fermentations |
Maturation/storage |
Pediococcus, Lactobacillus, Zymomonas, Pectinatus, Wild yeasts |
Sour taste and off-flavors with sulfury aromas, diacetyl, turbid beers |
Bright/packaged beer |
Pediococcus, Lactobacillus, Zymomonas, Pectinatus, Wild yeasts |
Sour taste and off-flavors with sulfury aromas, diacetyl, haze |
Cask-conditioned beer |
Acetic acid bacteria; Wild Yeast; Lactobacillus; Pediococcus; Zymomonas |
Aldehydic and acid beers sourness. Haze, off-flavors, and aromas |
Note: ATNC, apparent total nitroso compounds.
The elimination of microbiological spoilage potential is achieved by the rigorous adherence to several key principles:
The principles applied in the use of HACCP techniques are equally useful in identifying and nullifying the risks of microbial contamination (Chapter 18). In addition to the potential risks from brewhouse materials mentioned earlier, a number of other additions to the process can serve as sources of microbial contamination after wort has been boiled and cooled, namely:
Each must be assessed and the microbiological risks eliminated. Inadequate pasteurization regimes are often the cause of microbial problems in packaged beer, particularly in keg beers. Although these problems can be related to the incorrect application of the appropriate pasteurization units (PUs), the most usual cause is leakage in the cooling side plates of the pasteurizer. Modern plate-heat exchangers usually incorporate pressure differential systems to prevent such leaks (usually caused by pinholes in the plates) from leading to contamination of the beer stream with unsterilized water, beer, or coolant.
Beer packaging, notably into kegs and casks, should be carefully monitored to ensure that both the containers and filling heads are properly cleaned and sterilized. Similarly, filling heads on bottles and can lines must be maintained and cleaned thoroughly, although correct pasteurization of the filled bottle or can will usually prevent microbiological problems from developing.
Where microbiological problems do occur in brewing and packaging, it is usually worthwhile to complete a thorough microbiological audit of the process. The general aims of the audit can be summarized as follows:
This last part is important in that much routine microbiological testing is either worthless and unnecessary or inadequate. An audit is an opportunity to revisit current procedures and determine if they are really necessary. Many tests have been introduced on an ad hoc basis as a result of a specific problem, which may have occurred years earlier and is no longer relevant.
The methods used for identifying and enumerating the microorganisms found in brewing are well documented in the various recommended methods of analysis. Of particular interest in recent years has been the development of “rapid methods” designed to produce results either instantly or within several hours rather than the more traditional methods that can take several days or even weeks. These rapid methods include the use of adenosine triphosphate (ATP) bioluminescence for detection of microbial contamination and various molecular biology techniques largely founded on the polymerase chain reaction (PCR), which are used to amplify specific DNA sequences representative of the various spoilage organisms (see Chapter 18).
In addition to the use of PCR in microbiological monitoring, it can also be applied to the detection of genetically modified (GM) raw materials, which could be used in brewing. In the EU, foods that contain or are made from GM organisms are required to be labeled. Using a real-time polymerase chain reaction (Real-Time PCR), also known as quantitative polymerase chain reaction (qPCR), it is possible to accurately measure the levels of, for example, genetically modified maize in a consignment used for brewing.
Monitoring microbiological contamination by these rapid methods has developed extensively over the past few years, and the costs of reagents and equipment has been reduced to economic levels.
21.4.5 Sensory Analysis
The consumer’s perception of beer quality is usually based on a reaction to a complex mix of expectations associated with the effects of the following:
Many of these perceptions are outside the control of the brewer, but for those factors directly influenced by the brewing and packaging processes, the control of beer flavor and aroma are the most significant. Although the various analytical and microbiological methods referred to earlier provide fairly objective tools for identification and quantification, the very nature of the differing responses by the senses to different flavors and aromas makes this identification and quantification difficult.
Despite this fundamental limitation, brewers and flavor analysts have developed robust procedures that enable sensory analysis to be a valuable tool in the monitoring and control of beer quality. There are five basic types of flavor evaluation methods.9 In-depth details can be found in Chapter 27 for each of the following:
21.5 CUSTOMER AND CONSUMER FEEDBACK
Although one of our goals in meeting the customers’ requirements is a total absence of defects, it is unreasonable to pretend that this is achieved. Errors and mistakes do occur in servicing the needs of the customer and consumer, and where these errors do occur it is important that we have systems in place that can react appropriately to the complaint or feedback generated. These systems have three key objectives:
A complaint that is handled promptly and efficiently is usually appreciated by the customer. Although fraudulent claims do sometimes occur, the majority of complainants do have issues that they perceive as not delivering the quality promise of the supplier. The advent of telephone “helpline” and “careline” numbers and Web site addresses on the package facilitates ready access to suppliers by consumers, who are learning to complain more vociferously and effectively. It is essential that, in responding to these complaints—by telephone, letter, or e-mail, the business has procedures in place that address the needs of the customer. Of particular importance are the selection and training of the staff who will be communicating directly with the complainant.
Brewers are obliged to deliver to customers and consumers products that are safe and wholesome. Failure to do so could result in prosecution by regulatory authorities and/or by the customer for damages as a result of injury or ill health. Additionally, the publicity generated by such incidents could seriously damage the brand and manufacturer concerned. It is incumbent on suppliers to monitor complaints by customers and on consumers to identify products in the market that may be deemed to be unsafe and to take appropriate, rapid action to remove that product from sale and notify customers of the risk. Suppliers must have policies and procedures in place that address these potential incidents. Crisis management teams should be constituted and rehearsed to ensure that if and when these incidents occur the appropriate mechanisms are in place to effectively manage the process. Problems with glass in bottles make up the greatest proportion of these incidents, and it is important in monitoring complaints that staff are fully alert to the technical issues involved in identifying these problems.
Although we may have confidence in the effectiveness of our QMSs in order to meet our customers’ requirements, there may be instances where our controls and checks in the process are unable to detect or prevent faults in the product. The consumer will inspect and drink each pack or glass of beer we offer for sale. As such, our consumers can give us the benefit of a 100% inspection system. This information is extremely useful in highlighting and rectifying problem areas. In draft beers, when trade outlets complain of faults, it is important to categorize the fault. Typically, the supplying brewery will seek information on:
This information can be collated and used to identify and track particular problems. It is useful to benchmark the data collected with other brewers to highlight issues of concern. For example, two breweries in the same group producing the same beer in the same container size and in the same market, showed significant (twofold) differences in return levels. On investigating the returns data, the major difference was related to a high level of “flat” complaints in one brewery, which was traced to a breakdown in the plastic seals in the keg extractors caused by high sterilization temperatures on keg cleaning.
Similar considerations apply in the analysis of complaints from beers supplied in cans or bottles. Complaints are again categorized into defined faults, typically:
Many of these issues are not readily identified by periodic inspection of the end product, although this is not surprising given the statistical probability involved. Additionally, damage during the distribution chain from brewery to retail outlet or consumer’s house can often not be readily anticipated. This is particularly true of damage to cartons of beer, which is sometimes the result of poor basic design or failures in the gluing mechanisms on the line.
Effective customer and consumer feedback is essential in driving improvement, and it is important that the complaint-handling operation has the appropriate procedures and systems in place to report quickly on problems—both to activate a withdrawal of beer from trade if necessary and to stimulate corrective action in the process.10
Procedures are included as part of the QMS, and they set out the scope of the complaints process, defining roles and responsibilities, authority levels, escalation procedures, and handling standards and providing guidance on reimbursement levels. It is important that procedures for referring complaints to the complaints function are clearly understood across the business.
Systems are required to log, track, analyze, and report on complaint data. Although simple paper systems can be used, computer-based systems are now readily available to facilitate this process. Typically, the following information needs to be captured:
This information should be readily available and presented in the appropriate format.
21.6 PROCESS CONTROL
Having identified the factors that should be measured, monitored, and controlled in the brewing and packaging of beer, how do we establish that we have control of the process? We have seen that the innate variability of the raw materials used in brewing and the complex physical, chemical, biochemical, and biological transformations in the brewing process comprise a formidable challenge to the brewer to produce a beer that consistently meets the requirements of the customer. Controlling the inputs to the process should ensure that the outputs conform to the stated requirements and without recourse to unnecessary inspection of the outputs. The emphasis in process control is to ensure that by using data as feedback on the performance of a process, we can identify sources of variation and then work to reduce or eliminate this variation.
21.6.1 Variation
Variation or variability appears in two significantly different forms: common or natural variability and special or nonrandom variability. Natural variability occurs when a process is functioning normally and is invariably present. Because it is normal, this natural variability can only be significantly reduced by changing one or more inputs to the process (e.g., better plant or raw materials, procedural changes, improved methods of analysis, etc.). Nonrandom variability is the contribution to the overall variability that can be attributable to “assignable causes” (i.e., some specific, unplanned occurrence such as plant malfunction, analytical or operator error, or instrument calibration fault). These are features of a system that is not behaving normally and, unlike natural variability, nonrandom variability is amenable to being significantly reduced or eliminated entirely by the application of appropriate control procedures and remedial action.
A frequency distribution due to natural variability is called the normal distribution. This is represented by the classical bell-shaped curve (Figure 21.5), where the data can be defined in terms of the mean or average, with the standard deviation as the best measure of the spread of data around the mean. With data that conform to such a normal distribution, 99.7% of the data will fall within plus or minus three standard deviations of the mean value. It is not normally possible to fully characterize the total data population of interest. However, it is possible to gain a meaningful picture of that total population with estimates of the true mean and standard deviation by taking samples. In simple terms, with more samples, their means approach a normal distribution, even when the number of samples is relatively small (say three or four). If a process is operating within so-called statistical control (i.e., not subject to the influence of assignable causes), it is to be expected that the data points from the samples will be randomly distributed around the mean line and within plus or minus three standard deviations of the process means. This is the primary criterion for identifying a process being within or without statistical control. These data are used to construct control charts (Figure 21.6), which have the following basic features:
Figure 21.5 The normal distribution.
Figure 21.6 Control chart for variables.
These are usually located at distances representing plus or minus three standard deviations from the mean line.
Values plotted inside the control limits show that the process is stable and operating under the influence of random variability. Values outside the control limits indicate that the process is unstable and is subject to the influence of one or more assignable causes, which can be investigated and (hopefully) eliminated to bring the process back under control.
It is possible to have a process that is in statistical control but is delivering a product that is outside specification! This is illustrated in Figure 21.7. If the specification has been set too tight, then the process may not be capable of meeting that specification. This may demand either a change of specification or changes to the process to improve its capability to reduce the normal variation.
Figure 21.7 Control chart with control limits and specification limits.
Process capability can be measured relative to the control limits and the specification limits. Where the control limits and specification limits coincide, the process capability, Cp, is said to have the value of 1.0. Cp values of 1.0 or greater mean that the process is capable (i.e., can generate product that is all within specification). Cp values less than 1.0 mean that the process is not capable—the process will generate product that is out of specification. In practice, it is always advisable to target Cp values greater than 1.0 to allow for any slight drift in the average of the product and still produce in specification.
Although Cp values indicate whether or not the process is capable of producing within specification, it does not actually tell us that we are producing in specification. A further measurement, the capability index, CpK, is used to determine whether we are actually producing in specification. The CpK can be calculated from the relationship:
However, if the process mean is not centrally located, upper (CU) and lower (CL) capability indices are calculated:
The smaller of CU or CL is the capability index, CpK.
In situations of one-sided specifications (e.g., maximum haze or dissolved oxygen level or minimum head retention value), only the relevant of the two measures, CU or CL, will apply. Like Cp, a minimum CpK value of 1.3 is usually sought to allow for slight shifts in the process. As the CpK increases, the need for routine measurement decreases. Periodic checks on CpK are required to ensure that CpK is not decreasing, thereby increasing the risk of product out of specification.
The applications of statistical process control (SPC)11 are increasing in the brewing industry. In the United Kingdom, volume control of container contents and the control of alcohol levels in finished products is rigorously monitored by government authorities using statistical control methods that have been agreed upon with the brewing industry. Codes of practice have been published detailing the approved methods of calculation. However, in addition to these controls on finished product, SPC is being applied throughout the brewing and packaging processes to monitor and control them, minimizing the risks and costs associated with quality failure (rework, replacement of raw materials, scrapping of product, reinspection, rescheduling of production, etc.).
The application of SPC techniques has led to the development of the Six Sigma approach to business improvement and has been adopted by many organizations throughout the world. Six Sigma equates to the six standard deviations referred to in the normal distribution curve and provides a focus for reducing the variation in all work processes by developing a structured approach for improvements in process capability. A detailed review of Six Sigma techniques is beyond the scope of this chapter, but for more information refer to Six Sigma for Managers by Brue.12
21.7 BEER QUALITY AT THE POINT OF SALE
It could be argued that the responsibility of the brewer for the quality of beer ends at the brewery gates. However, “meeting the customers’ requirements” extends beyond the brewery gates, particularly at the point of presentation of draft beer. Much of the good work done in the brewery and packaging hall can be undone by a lack of care and attention in the cellar and bar. A detailed review of cellar management and bar practice is beyond the scope of this chapter, but the reader is referred to the paper by Buggey et al.,13 which highlights the important features of ensuring good quality beer at the point of sale. Effective stock control, correct storage conditions, good hygiene, appropriate dispense equipment, clean glassware, and, critically, staff training, are all issues that need to be addressed.
Brewers have an important role in educating their customers to ensure that the consumers’ requirements and expectations are at least met and preferably exceeded. Beer is arguably “the best long drink in the world,” and it is incumbent on those involved in the brewing industry supply chain—suppliers, brewers, packers, distributors, and retailers—to deliver products and services to the highest standards of quality.
ACKNOWLEDGMENTS
The author would like to thank Laurence May of Carlsberg UK for his considerable assistance in the revision and updating of this chapter.
REFERENCES
1. Oakland, J.S., Total Quality Management and Operational Excellence: Text with Cases. 4th ed., Routledge, New York, 2014.
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3. Lorca, T.A., Why should the malting and brewing industry be concerned about food safety? Part 1, Tech. Q. Master Brew. Assoc. Am., 53:34–38, 2016.
4. Campden BRI, TACCP. Threat Assessment and Critical Control Point: A Practical Guide, Campden BRI, UK, 2014.
5. BRC Global Standard for Food Safety Issue 7, BRC Bookshop, London, UK, 2015.
6. Baxter, D., The influence of brewing liquor on beer safety and quality, Ferment, 12:13–18, 1999.
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10. Powesland, T., Consumer feedback, in Excellence in Packaging of Beverages, Browne, J. and Candy, E., Eds., Binsted Group Plc., Hook, 2000, pp. 703–707.
11. Oakland, J.S., Statistical Process Control, 4th ed., Butterworth–Heinemann, Boston, MA, 2002.
12. Brue, G., Six Sigma for Managers, McGraw-Hill Education, New York, 2003.
13. Buggey, L.A., Bennett, S.J.E., and Pain, M., Beer quality at the point of sale, Brewer Int., 2:15–19, 2002.