Grinder Burr Sizes Explained – From 38 to 102 mm

Grinder Burr Sizes Explained – From 38 to 102 mm

The quiet rattle as the beans disappear between the burrs, and seconds later a fine, warm scent rising from the chute. What happens in there decides a good part of what ends up in the cup.

At the heart of every coffee grinder sit two burrs that cut the bean apart rather than crushing it. How large these burrs are shows up in every product description as a bare millimeter figure, 38, 64, 80, sometimes over 100. On its own, a number like that says little. In context, it paints a clear picture of how a grinder behaves while grinding, and why Coffee Coaching Club carries such different sizes side by side, from the compact hand grinder to the commercial grinder.

Why size changes anything at all

The larger the burr, the more cutting surface is available for the same amount of beans. More surface means each particle spends less time on average between the burrs before falling through, and the friction heat that's generated spreads across a larger surface instead of concentrating. Larger burrs therefore tend to grind cooler and more evenly, with less fines, while smaller burrs process the same amount of beans in a tighter space. We described exactly this principle, surface instead of force, in our comparison between the Weber EG-1 and the two Lagom grinders from the chemist's perspective; here it's about the principle across the whole CCC range.

Then there's the shape: conical burrs, set cone-within-cone, usually turn more slowly and are considered especially gentle on delicate, lighter roasts. Flat burrs, two parallel discs stacked on top of each other, often run at higher RPM and tend to produce more body in the cup. Which grinder feels right is ultimately just as subjective as choosing a car engine, there's no objectively best one, only what fits your espresso. That's our observation on it, one of many in the coffee world.

At a glance

Burr sizes across the CCC range
Comandante C40 (hand grinder)	Conical. Comandante itself doesn't state an official millimeter figure for burr size.
Timemore Chestnut C5	42 mm, conical (patented S2C burr)
Varia VS3	38 mm cutting diameter (48 mm outer diameter), conical, 6-Core Supernova
Varia VS4	53 mm, conical, 6-Core Supernova
Mahlkönig X54	54 mm
Eureka Mignon Specialità	55 mm, flat
Mazzer Mini G / Philos	64 mm, flat
Fiorenzato F64 Evo Sense	64 mm, flat
Mahlkönig E65S	65 mm
Varia VS6	58 mm flat (stock) or 63 mm conical (upgrade)
Weber Workshops EG-1 / Option-O Lagom P80	80 mm, flat (Mizen burrs on the Lagom)
Mahlkönig E80S	80 mm
Weber Workshops HG-2 / Key	83 mm, conical
Option-O Lagom 01	98 mm (standard) or 102 mm (XL Blind Burr), flat

Which size makes sense for whom

For anyone who wants to start small or stay deliberately compact: hand grinders like the Comandante C40 or models from our Timemore collection show that even smaller burrs deliver excellent espresso, as long as grind size and dose are dialed in. For anyone who wants larger volumes, higher speed, or maximum consistency across many shots, the sweet spot tends to sit at 80 mm and up, for instance with the Weber Workshops EG-1 or the Option-O Lagom models, but also with commercially-oriented brands like Mahlkönig, Eureka, Mazzer, or Fiorenzato in our range. None of these sizes is the one right answer, it's your decision how much surface you want and need.

A grinder calls for the right machine and the right scale. For espresso machines, our advisor tool helps you choose. For the scale, the same logic as with the burrs applies: for anyone who wants it compact and precise, the Normcore collection is the natural choice, and anyone who wants app connectivity and a flow-rate display finds that with Acaia.