Fig 1.
Coffee brewing control chart example for drip filter coffee. The coffee quantities marked are for use with 1 kg of water.
Fig 2.
Schematic of the experimental set-up.
Fig 3.
Coffee particle size distributions.
Particle size distribution for both fine and coarse grinds.
Table 1.
Fine and coarse grind particle size distribution measures.
Table 2.
Coffee grain parameters for fine and coarse grinds for both single grain and two-grain CFD and 1-D models.
Fig 4.
Cylindrical case computational domain.
Cylindrical case computational domain with included boundary conditions.
Fig 5.
Conical case computational domain.
Conical case computational domain with included boundary conditions.
Fig 6.
Numerical and experimental results cylindrical case.
Comparison between experimental (Expt data) and numerical outlet coffee concentrations for different models for the fine grind ((a) and (b)) and the course grind ((c) and (d)).
Fig 7.
Liquid velocity and pressure profiles conical case.
Velocity and pressure profiles of the liquid observed in the 1-D cone model (solid line) and in the CFD model at the centre line of cone (dashed lines) for fine and coarse grinds ((a) and (b)). Velocity and pressure profiles of the liquid observed for fine coffee within the CFD model ((c) and (d)).
Fig 8.
Numerical simulations for conical case.
Comparison of numerical models of coffee extraction in the conical geometry using the two grain model for the fine and coarse grinds. Parameters listed in Table 2.
Fig 9.
Time evolution of soluble coffee.
Time sequence of the remaining soluble coffee concentrations in the coffee bed using the CFD model for the fine coffee grind.
Fig 10.
Espresso control chart with extraction uniformity.
Coffee brewing control chart for espresso strength preferences. The espresso strength categories are adopted from ref. [10].