The grinder matters more than the brewer. It decides how even your coffee is, and evenness decides how sweet and clean it tastes.
Most good grinders use burrs. Burrs are two metal rings that crush the beans. They come in two main shapes.
Conical burrs
A cone sits inside a ring. Beans fall in from the top and are crushed as they move down.
Conical burrs tend to produce a wide range of particle sizes. That gives body and a rounder cup. They are also quieter and easier to build into hand grinders.
Flat burrs
Two flat rings face each other. Beans pass through the gap in a straight line.
Flat burrs tend to produce more even particles. The cup is often clearer and more distinct. Many cafés use them for espresso and filter.
How to choose
Choose conical if you like body, brew with immersion or want a lower price. Choose flat if you like clarity and brew with pour-over.
The best burr is the one you will clean and use every day.
Size matters too. Burrs of 64 millimetres (2.5 inches) or more are common in cafés. Home grinders usually use 40 to 58 millimetres.
One more thing
Retention matters. Grounds that stay in the grinder go stale. A small brush or a puff of air between doses helps.
