Setting Up Your Distillery’s Sensory Program for Success

In a previous article, we looked at the three main types of sensory tests and the biases that can occur when executing those tests in your distillery. Here, we look at how to recruit the most effective evaluators and how to properly conduct sensory evaluations.
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Evaluator Recruitment

Although it may sound simple, recruiting the right people to taste and evaluate your spirits is no easy task. A candidate needs several important qualities to be a successful judge of spirits.

First and foremost, any potential evaluator must be motivated. Ask almost anyone on the street whether they want to try some free samples of booze, and they’ll probably say yes—however, a willingness to drink free spirits does not make someone a good evaluator. Well-executed sensory sessions take time, and following the proper procedures to obtain good results can be laborious. Good evaluators must be committed to the entire sensory process, and they must abide by the rules set out for them. If a candidate seems more interested in showing up to party—or worse, not showing up at all—then they need to be removed from the pool of applicants.

The second quality that potential evaluators need to possess is the ability to properly taste the spirits. The National Institute of Health estimates that one in eight people over the age of 40 have some form of anosmia—the technical term for lack of smell. This means that a significant portion of your potential candidates may be either partially or totally blind to a specific smell or taste. Furthermore, as much as one third of the world’s population has some form of hyperosmia—an increased sensitivity to certain volatile smells. This means that some evaluators may be overwhelmed by the aromas of your spirits. To eliminate candidates who could throw off your assessments, you can evaluate each candidate using a number of different screening methods.

Here are some of the most common screening tests.

Matching Test

A matching test can determine whether a candidate can correctly pair like samples. To run this test, present the candidates with a set number of reference samples. Give them time to evaluate these samples; you can even tell them exactly what sensory notes each sample represents. The candidates then return their reference samples and receive a new set of the same samples—but this time in a random order. Then the candidates must try to match the new samples to the original reference samples.

Detection Test

Use a detection test to determine whether a candidate is blind (anosmic) to specific aromas or flavors. Present the candidates with a difference test, in which they must correctly identify samples that have been spiked with extra flavor compounds. The exact parameters can vary depending on the compounds and the complexity, though often simple triangle tests (in which you present two identical samples and a different one) are used.

Ranking Test

Use a ranking test to determine a candidate’s sensitivity to specific aromas or flavors. In this test, give the candidates samples that have been spiked with various amounts of a chosen flavor compound. Then, ask the candidates to rank-order them from lowest to highest intensity.

These aren’t the only screening tests available to sensory scientists, and there are many more that can be used depending on the situation. Also, it’s important to note that if a candidate does not pass all the tests with which they are presented, they may still be considered a successful evaluator. Every human is different, and certain individuals will naturally be better suited to identifying or ranking specific flavor and taste perceptions. These tests are simply designed to identify and describe an evaluator’s abilities. It’s up to the person running the sensory tests to determine whether the candidates will be able to give valuable feedback.

Finally, the last quality a good evaluator needs is consistency. Humans are ever-changing, and our tastes and preferences evolve over time. For a tester to be able to compare the results of two experiments given at two different times, they need to know that their evaluators are scoring things consistently. This means that evaluators’ feedback should be scrutinized regularly to see whether individual tastes or preferences have changed. A change in profile isn’t necessarily a bad thing; but it’s important to know if you want to compare like data.

Running a Sensory Session

Once you’ve selected the perfect team of evaluators, it’s important to teach them how to properly conduct sensory analysis. As I mentioned in the previous article, bias is the enemy of good sensory science, and the best safeguard against bias is proper testing techniques. By outlining to the participants exactly what you expect of them, and by giving them the space and time to conduct their evaluations properly, you can ensure valid, repeatable results.

A good sensory test takes a lot of preparation—both on the part of those running the test and of those participating in it. Evaluators should not wear any strong-smelling cologne or perfumes so as not to confuse other participants. In addition, they should not smoke before entering the test space; and, preferably, they should not eat or drink for least 30 minutes before the testing. This can be tricky to enforce because the best time to do sensory evaluation is mid- to late morning, when tasting ability is at its peak.

Upon arrival at the testing site, evaluators should be familiarized with the tests in which they’ll participate and with what is expected of them. A prepared information sheet is helpful here. By using an information sheet rather than an in-person presentation, you reduce the possibility of accidentally introducing personal bias. It can also save time.

Once the test is ready, evaluators should enter the testing space without any idle conversation or chit-chat. Most tests are conducted individually, and excess talking can introduce different forms of bias. If it’s necessary for evaluators to talk during testing, conversations should be kept short and to the point. Furthermore, the testing space should be relatively quiet with as few distractions as possible. Many large companies have testing facilities that are painted specific colors, and they keep these rooms at constant temperatures and light levels to reduce distraction.

During the test, serve the samples in the correct order with clearly marked identifiers. Ideally, prepare all samples in advance; however, if this is not possible, be sure not to pour them within sight of the evaluators. Provide the evaluators with either a pre-made evaluation form or blank scratch paper to record their thoughts.

Allowing the correct amount of time for the evaluators to complete the test is vitally important. If you or the test conductor sees a participant rushing through samples, make a note and analyze their submissions for possible inconsistencies or errors. Also make a note if the test appears to cause any sensory fatigue among the evaluators. If so, it may be necessary to redesign and administer the test in a way that is less taxing.

Finally, after the test is complete, collect all evaluation forms and any scratch paper. If it’s appropriate to the test, the evaluators may engage in conversation or ask questions of the test conductors; however, this is on a case-by-case basis.

Finding the most effective evaluators and properly conducting your sensory evaluations demands rigor—but it is important to get it right. By developing a routine and training your evaluators, you’ll be able to conduct efficient, repeatable sensory studies that give you valuable data—and help you to consistently produce the spirit that you’ve envisioned.