Specialty Coffee Extraction Science: How Micron Uniformity and Burr Geometry Shape Flavor

Coffee brewing is the chemical process of dissolving soluble compounds (caffeine, organic acids, lipids, and carbohydrates) from roasted coffee grounds using hot water. The golden extraction yield targets between 18% and 22% of the coffee bean mass.

In a coffee grinder, burrs don’t just slice coffee into uniform spheres; they crush beans into a spectrum of particle sizes, including boulder fragments and microscopic "fines." If a grinder produces excessive fines, those microscopic particles over-extract within seconds, releasing bitter, drying tannins.

Flat burrs, like those found in the Fellow Ode Gen 2, cut coffee with parallel rotational shearing, resulting in a tight unimodal distribution curve. This allows pour-over brewers to extract maximum sweetness, acidity, and origin character without harsh drying astringency.