Written by GARY SPEDDING, PH.D.
SENSORY THRESHOLDS Do You You Know Know Yours? Yours? Do
n interesting question was raised recently regarding the sensory evaluation of bourbon and rye whiskies with there being a lack of discrimination via sensory descriptive analytes. This topic was raised via the release of a publication by Lahne et al., (2019). Without going into too much detail about any contention of such findings, this begets the question; “Do we know enough about the chemical and sensory complexity of distilled spirits?” The simple answer is no. We do not (yet) have details such as the (accessible) threshold values whereby we can assess the relative amounts of many of the key components in our favorite spirits. Though the current research is helping to clarify the situation, at least with respect to the chemical component aspects, distillers still lag far behind brewers and enologists when it comes to full sensory evaluation of their products. The training of sensory evaluation teams is a complex topic and often starts with the spiking of products with known amounts of pure chemical components to elevate the actual flavor impression in order for them to learn how to describe and identify such flavors or for aroma purposes only — spiking such components into “sniff ” bottles containing water- or spirit-soaked cotton 1
balls. Following such trainee evaluations, the sensory descriptors are discussed and, when possible, more technical, rather than simple hedonic descriptors, are learned, memorized, and applied to subsequent tastings. It is best if all members of a panel are on the same page and know the basic chemical names of components. This makes life easier for the sensory panel team leader. Sensory biases must be avoided, and an understanding of the sensitivities of individuals to specific components needs to be understood as some individuals are sensorially “blind” (having anosmia1) to certain compounds. Individuals thus vary greatly in detecting and identifying many different aroma components. While we use the term or concept of taste to describe food and beverages, taste or rather overall flavor perception is a combination of all the senses; smell (olfactory), taste (gustatory), trigeminal sensations (pain/irritation, warming, cooling — mouthfeel “touch” and viscosity) and even sight (color) and sound (effervescence for carbonated products). Flavor impressions are, however, disproportionately olfactory (smell) based. Moreover, synergistic and antagonistic interactions are at play in how the human senses and brain interpret flavor information with such implications described
recently by Barwich and Smith (Barwich, 2020; Barwich & Smith, 2022), with the complex nature of flavor and both machine and human sensory evaluations covered by Chambers and Koppel (2013). Further details are not described here. (See Artisan Spirit issues 12, 16, 22, 28, 29, and 39 for more on general sensory and descriptors — the latter concerning the sensory training tool and memory jogger — The Flavor Wheel.) The basis of this article is to go beyond the basics of establishing flavor descriptors and to allow tasters, or taste panel leaders, to better understand the sensitivity of individuals in defining appropriate flavor attributes. Ultimately leading to their learning of the relative concentrations of such components and to be able to quantitatively determine with some degree of accuracy the amounts of various components present in a food or beverage. This will enable a better characterization of the differences and similarities in products and provide better overall profile descriptions of a brand, a new formulation, or competitive product. This then allows for an understanding of the origins and controls of both off-flavor notes and desirable qualities and for better discrimination of those bourbon vs. rye whiskies alluded to above.
What is Anosmia? https://jamanetwork.com/journals/jama/fullarticle/2767634
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