From Light to Dark: Temporal Sensory Perception of Fermented Coffee by Trained and Consumer Panels

The consumption of specialty coffee has been growing and attracting an increasing number of enthusiasts both in Brazil and worldwide. Annually, new research is conducted to understand consumer perceptions regarding the nuances of this beverage. This study aimed to explore the sensory perceptions of specialty coffees using the Temporal Dominance of Sensations (TDS) methodology across different roast levels, comparing responses from trained panels and regular consumers. Using samples of Coffea arabica from Minas Gerais in Brazil, the study applied the TDS technique to assess the sensory impact of three distinct roast levels (light, medium, and dark) on both primary (category-level attributes per the SCA Flavor Wheel) and secondary (sub-category descriptors) attributes. Coffee samples were analyzed by a panel of trained evaluators based on the Q Grader training protocol and a group of regular specialty coffee consumers. The results revealed distinct sensory profiles across roast levels, with notable differences between trained panelists and consumers. Light roasts were associated with sour and fruity notes, especially by trained panelists, while consumers more often perceived bitter and fermented attributes. Medium roasts showed greater sensory balance, and dark roasts were predominantly bitter for both groups, though trained panelists also identified fermented and alcoholic notes more clearly. Trained evaluators demonstrated greater sensitivity and were able to discern a wider range of sensory attributes. In addition, they spent less time selecting the first sensation and showed higher dominance rates for most attributes compared to the panel of regular specialty coffee consumers for both primary and secondary attributes. This divergence not only emphasizes the role of sensory training in enhancing perceptual acuity but also underlines the importance of aligning coffee sensory claims with consumer expectations and perception.