3.1. Coffee Consumers Group Identical Samples and Separate Coffees Based on Roast Level and Storage Condition

In Figure 2 , the consensus product map for the 12 evaluated coffee samples shows that coffee consumers were able to discriminate between light and dark roast coffees, as all light roast “City” samples are positioned on the left-hand side of the MFA map while all dark roast “Vienna” coffee samples are positioned on the right-hand side. Further, the 95% confidence ellipses obtained via a bootstrapping algorithm do not overlap between the two roast levels, indicating that the coffee samples smelled perceivably different. Overall, coffee consumers were also able to place the blind duplicate samples close to each other, with all blind duplicated samples showing overlapping confidence ellipses. This indicates that participants perceived the duplicated samples as similar and that participants were able to execute the PM task.

Roast level separates the samples along the first dimension, explaining 32% of the overall variance, with the lighter roast “City” samples on the left-hand side and the darker roast “Vienna” coffees on the right-hand side of the map. Along the second dimension, explaining another 14% of the total variance, samples are separated due to storage conditions, with freshly roasted and freezer-stored samples positioned at the bottom of the map and room temperature-stored coffee samples positioned towards the center or top of the map.

Looking within the two different roast levels, it becomes apparent that differences due to storage conditions are more dramatic for the dark roast “Vienna” samples than the light roast “City” samples. All “City” roast samples are placed close to each other with overlapping confidence ellipses, indicating that the changes due to storage conditions (fresh roast CN vs. freezer storage CF vs. room temperature storage CR) are less apparent for the lighter roast coffee. In contrast, for the dark roast “Vienna” samples, storage conditions led to perceivable and clear differences with consumers positioning the room temperature-stored samples (VR) far from the freshly roasted VN and freezer-stored VF “Vienna” samples. These differences are also statistically significant as the confidence ellipses of the VR samples do not overlap with any of the other dark roast (VN, VF) or light roast (CN, CF, CR) samples.