Effect of Basket Geometry on the Sensory Quality and Consumer Acceptance of Drip Brewed Coffee

Abstract

In this work, discrimination tests, descriptive analysis, consumer tests, and total dissolved solids (TDS) were used to evaluate the effects of brew basket geometry on the sensory quality and consumer acceptance of drip brewed coffee. Two basic geometries, semi‐conical and flat‐bottom, were evaluated in conjunction with coffee roast and particle size. Initial discrimination tests showed that small differences in median particle size were not discernable, but that coffees brewed using either semi‐conical or flat‐bottom filter baskets were significantly different (P < 0.05, N = 45). Additionally, coffee brewed in the semi‐conical basket had significantly higher %TDS, and we estimated a sensory difference threshold of 0.24 %TDS. A subsequent descriptive analysis (DA) showed significant differences by roast for 11 attributes and by grind for six attributes. Although brewing geometry, as a single factor, was only significantly different for three independent attributes (smoke aroma, sweetness, and tobacco flavor), roast × geometry interactions were significant for six attributes (berry flavor, bitterness, burnt wood/ash, citrus flavor, earthy flavor, and sourness) and the grind × geometry interaction was significant for two attributes (bitterness and floral aroma). Attributes showing significant interactions with brewing geometry were also key drivers of consumer liking/disliking. Overall consumer liking (9‐point hedonic scale) was analyzed by cluster analysis (N = 85), which revealed four distinct preference clusters. For each cluster, a particular basket geometry and/or roast level showed lesser acceptance. Overall, the results strongly corroborate the hypothesis that basket geometry affects the sensory quality of drip brewed coffee. Practical Application Most Americans consume drip brewed coffee. Improving our understanding of the effects of basket geometry, roast level, and grind size on the total dissolved solids, sensory properties, and acceptability of drip brewed coffee gives producers and consumers alike an opportunity to optimize the sensory quality of their coffee.

Effects of brew strength, brew yield, and roast on the sensory quality of drip brewed coffee

“…Additionally, the highest intensity of rubber flavor was found in the dark roast coffees, but a significant response surface was only obtained for light and medium roast; thus, all dark roast coffees were perceived to have the same intensity of rubber flavor, but rubber flavor could be modified in the light and medium roast coffees by brewing. These four attributes (smoke/acrid aroma, tobacco flavor, woody flavor, and rubber flavor) are common descriptors of dark roast coffee, and their impact on consumer preference has previously been shown (Frost et al, 2019).…”

“…As shown in Figure 1, the nine overlaid zones on the Brewing Control Chart each express a different brewing quality; for example, a brew with low PE and high TDS is designated as a "strong under developed" coffee, while a brew of high PE and low coffees from 14 different countries and comprises over 100 aroma and flavor attributes (Chambers et al, 2016). This flavor complexity stems from a wide variety of processing conditions throughout the production chain, including cultivar (Razafinarivo et al, 2013), various agronomic practices (Tolessa, D'heer, Duchateau, & Boeckx, 2017;Vaast, Bertrand, Perriot, Guyot, & Génard, 2006), postharvest processing (De Bruyn et al, 2017), roasting (Czerny & Grosch, 2000;Schenker et al, 2002), and brewing (Batali, Frost, Lebrilla, Ristenpart, & Guinard, 2020;Caprioli, Cortese, Sagratini, & Vittori, 2015;Fibrianto et al, 2019;Frost, Ristenpart, & Guinard, 2019), with each step impacting the final coffee flavor.…”

“…Despite much evidence that the brewing method helps govern which possible flavors will be expressed in a given coffee (Caporaso, Genovese, Canela, Civitella, & Sacchi, 2014;Frost et al, 2019;Gloess et al, 2013), there has been little systematic investigation. The most detailed work to date correlating the brewing indices of TDS and PE to sensory quality has focused on espresso coffee.…”

Comparison of preference mapping with projective mapping for characterizing consumer perception of brewed black coffees

“…These authors also reported that sensory differences in coffee were apparent preroasting, but became much more apparent following the roasting process. Furthermore, a recent study by Frost, Ristenpart, and Guinard () showed that product features have specific associated sensory effects. For example, brew basket design, independent from other features, significantly affected smoke aroma, sweetness, and tobacco flavors, while differing grind sizes and roasts had several uniquely connected sensory distinctions.…”

“…Previous studies have approached the differentiation of coffee consumer groups using various stimuli and methodologies. From a sensory perspective, consumer‐focused literature on coffee suggests that consumer groups are primarily differentiated by roast, with most consumers preferring an intermediate intensity with moderate bitterness and roasted flavors, while a smaller group prefers bolder, more intense coffees (Frost et al, ; Varela, Beltrán, & Fiszman, ). However, it should be noted that more specific secondary drivers for coffee consumer segments have been noted in the cited studies, among others.…”