Lesson 6 - Sensory Analysis

The sensory panel is the name given to the group of people that undertakes the sensory evaluation of the beer. In this section we discover the methods used to find the right panellists for the analysis that needs to be undertaken.

The perfect panellist

Our perfect panellist for a test will depend on the nature of the test. In a preference test we are only interested in how well liked a beer is. Therefore, we are not looking for special abilities. We just need the panel to reflect the demographics and preferences of the target consumers. For example, we would not have people with a love for double IPAs on a panel that is preference testing helles lagers. Members of a panel undertaking preference testing also need to be capable of understanding what they are required to do and to be motivated to undertake the test seriously. For this kind of test, panel members only need training on the test procedure.

Discrimination or difference tests are tests where assessors are asked if beers are different to each other and to identify the difference. When selecting panels for these tests, we need to ensure the assessors can detect and report the presence of an attribute that is essential to the acceptability of the beer being analysed. As with most physical attributes, there is variation from person to person with regard to sensitivities to smells and tastes. A small percentage of people are unable to detect certain smells (specific anosmia) and tastes (specific ageusia). Some have absolutely no sense of smell (congenital anosmia) or taste (congenital ageusia) from birth.

As well as having the capability to detect and report key flavours, our assessor must be:

• Motivated

• Regularly available at the time of the panel

• Allowed to attend by their manager (if from brewery staff)

• Healthy (free from specific allergies or treatment by certain medication)

• A moderate consumer of alcohol

In descriptive tests, our panellist must also have a vocabulary that is sufficiently developed to allow them to contribute to the test in the relevant language.

We now know what we are looking for in the perfect beer taster. Next we consider how to find them.

Screening and selection

There is some debate as to whether we should train tasters before we screen their capabilities. Research shows that if we train tasters before screening, the proportion found to be capable increases by a factor of at least two. It is important to note, the training will not improve their innate smelling or tasting abilities, but will help them to identify and describe what they can smell or taste. A common and practical approach is to screen for sensory blindness to key elements before undertaking any training to remove any assessors who are not capable.

To train our prospective panellists before screening, we conduct the same type of test that they will encounter as a panel member and we use a range of samples which represent the normal spread in any screening test. For descriptive tests we need to introduce the language that they should use to describe key flavour attributes. In subsequent training it is a good idea for experienced assessors or the trainers themselves to be involved in any descriptive test. This enables the prospective panellists to learn from their knowledge.

The best method to determine if a prospective panellist is capable of carrying out a particular analysis is for them to undertake a test on products where we have already established the correct outcome. To eliminate the possibility that the candidate got the right answer by chance, the test should be repeated more than once. To ensure our flavour panels yield consistent results, we need to select those who are able to perform consistently; as such, performance data over a number of tests should be evaluated where possible. This of course should not mean we exclude all but the very best performers from panels. A smaller panel of excellent tasters may be statistically less efficient than a larger panel including poorer tasters. That said there is little point adding poor tasters just to make up the numbers. Also, if there is not a sufficient number of panellists available, more frequent use of the limited number will not necessarily give the same result as a larger panel. Every type of test will have a recommended range of numbers of panellists. These must be complied with to ensure data validity. As a general rule, fewer trained/screen panellists are required to provide statistically significant results than is the case with novices. Because they are trained to recognise particular attributes and know how to complete the test protocol, there is less statistical noise associated with the test and hence a higher confidence level for the results. For difference tests and the trueness-to-type test, panellists who regularly taste and/or consume a brand provide the most valuable results.

To maintain motivation and effectiveness it is important that panellists regularly participate in panels. It is also important to assess their capabilities regularly. Our ability to taste and smell changes with age and our physiological state, so regular reassessment will ensure all panellists are still competent and data valid.

Where panels are made up of brewery staff, incentives for participation are commonly used.

Rules for assessors

Assessors should comply with the following rules to ensure that they are at the best of their abilities in the sessions:

• No smoking before sessions

• No eating or drinking 30 minutes before a session

• Do not attend a session if intoxicated or tired

• Do not attend a session if suffering from an illness or taking medication that will affect sensory abilities (cold, hay fever, migraine, Covid-19 etc.)

• Do not wear perfume or use strongly perfumed cosmetics and laundry products

• Ensure you do not have noticeable body odour

• Wash hands using unperfumed soap

The ability to taste is greatest late in the morning, so scheduling sessions for this time should yield the best results. We need to ensure the assessors arrive on time and that sufficient time is allowed between their arrival and the start of the test, so that samples are not sitting awaiting them for extended periods.

Now that we have assembled a collection of capable and motivated sensory assessors, the next step is to discover how the tasting room is designed and should be run.