Grinder Comparison: Flat Burr vs. Conical & Burr Size

The grinder shapes your coffee more than almost anything else. Explore how flat or conical burrs and burr size change the particle distribution – and thus whether your cup leans towards clarity or body and crema.

Particle Distribution Instead of Marketing

Every grinder doesn't produce a single particle size, but an entire particle size distribution. The shape of this curve determines the character in the cup. Two key factors shape it: the grinder's design and the size of the burrs.

Flat Burrs: two flat burrs tend to produce a tighter, more even distribution with fewer fines. This boosts clarity and defined aroma separation – suitable for light, fruity roasts and filter coffee. Conical Burrs: a cone within a ring tends to produce a wider, often bimodal distribution with more fines (finest particles). This provides body, crema, and chocolatey sweetness – suitable for classic espresso.

Burr Size: larger burrs (80, 98, 102 mm) tend to produce a tighter distribution and less friction heat; smaller ones (38–64 mm) tend to produce more fines and thus more body. Fines are a double-edged sword: they contribute to mouthfeel, but too high a proportion can lead to over-extraction and channeling.

There's no better or worse – both styles are legitimate. The taste in your cup decides.

Sources: Uman et al. (2016), “The effect of bean origin and temperature on grinding roasted coffee", Scientific Reports 6:24483 (measured particle distributions); Cameron, Hendon et al. (2020), Matter 2, 631–648 (fines, extraction, and channeling). Curves are schematic.

Finding the Right Grinder

Which grinder suits you depends on your style. Browse our coffee grinders – from compact single-dose grinders to flat-burr flagships. If you want to upgrade your grinder, you'll find high-precision burrs among the SSP grinding solutions. The Grinder Simulator and the Extraction Simulator show how grind size interacts with ratio and pressure.

Frequently Asked Questions

Flat or conical – which is better?

Neither is generally better. Flat burrs tend to deliver more clarity and aroma separation, while conical burrs provide more body, crema, and chocolatey sweetness. Light specialty roasts often benefit from flat, classic espresso from conical.

What are fines?

Fines are the finest particles in the ground coffee. They contribute to mouthfeel and body, but too high a proportion can lead to over-extraction (bitter) and promote channeling in the puck. Conical grinders and finer grind settings produce more fines.

Are larger burrs better?

Larger burrs tend to produce a more even distribution and less friction heat, which promotes clarity. However, this is a matter of style and budget – small, good grinders produce excellent espresso with more body.

Which grinder for light roasts?

For light, fruity single origins, large flat burrs are well-suited because they cleanly separate the aromas. For dark, chocolatey roasts and classic espresso, conical burrs are a strong choice.

You can find all interactive tools bundled in our Coffee Tools.