Materials and Methods
Coffee origin and preparation
Roast level, brewing basket geometry, and grind distributionwere evaluated for each experimental phase as indicated. Twocommercially available specialty coffees were used. The roast level of each coffee was determined according to the AGTRON/SCAAgourmet scale (Staub, 1995). The dark roast (Agtron 32.0) was ablend of Latin American origin and the light roast (Agtron 48.8)was a blend of Colombian and Ethiopian origin. Two basket ge-ometries were compared: a ﬂat-bottom basket, and a semi-conicalbasket (Figure 1). A Breville Precision brewer was used to brew thecoffee, since it was designed to easily allow the semi-conical basketto be inserted directly into the ﬂat-bottom basket and thus alter thebrew basket geometry. All coffee was ground using a Mahlk¨onigGuatemala Lab Grinder set to either grind number 3, 4, or 5. The particle size distribution (Figure 2) for each coffee at each of the three grind settings were measured in triplicate using a SympatecHELOS/RODOS laser analyzer (Sympatec GmbH, Clausthal-Zellerfel, Germany) equipped with the Sympatec Vibir vibratory feeder and the R7 lens (18 to 3,500 µm). The coffee industrylacks standardized names for speciﬁc grind sizes. For the purposeof this work, we refer to the smallest grind with median particlesize approximately 800 µm as “ﬁne,” the intermediate grind withmedian particle size of approximately 1,000 µm as “medium,”and the coarsest grind with median particle size approximately1,200 µm as “coarse.” We emphasize that these designations mightdiffer from descriptions sometimes used qualitatively in the cof-fee industry; the grind sizes used here were chosen to bracket therange of grind sizes commonly used for drip brew, and are denotedas “ﬁne” or “coarse” in comparison to each other.