Filter coffee brewing is a textbook example of flow through a porous medium. The governing equation is :
As the brew saturates, the concentration gradient diminishes. Without flow, extraction stops at equilibrium (limited solubility). In percolation, fresh water constantly renews the gradient, maintaining a high mass transfer coefficient. This is why pulse pouring (multiple small water additions) yields higher extraction than a single pour—it disrupts the stagnant boundary layer around particles. the physics of filter coffee pdf full
Covers the properties of brittle vs. ductile materials and how particle size distribution affects flavor. Percolation Mechanics: Filter coffee brewing is a textbook example of