Flat burr
F / DISC × 2Facing discs. Beans enter at the center and move outward through successive cutting stages.
APRIL DAISY LAB · COFFEE TOOLSGrinder
Grinder
Burr Guide.
Two layouts, many distributions. Explore how particles are made before asking which burr is better.
FIELD NOTE / 00
Curve height and width cannot be generalized across flat and conical burrs without matching beans, target grind and measurement method.
01 / FORM
Flat and conical burrs
Start with the burr arrangement, then see what a useful distribution comparison requires.
Conical burr
C / CONE + RINGAn inner cone and outer ring. Beans pass between their surfaces through successive cutting stages.
These exploded plates explain the paired structure. Check the specific grinder to identify which burr is fixed or rotating.
Reading a particle distribution
PSD / CONCEPTThe horizontal axis shows particle size in µm; the vertical axis shows relative amount in equal size intervals. Both curves are teaching examples with the same median.
Curve height and width cannot be generalized across flat and conical burrs without matching beans, target grind and measurement method.
Choose by the burr set
APPLICATIONEspresso
A suitable fines fraction and repeatable flow matter. Both layouts can work. Examples: Niche Zero (conical), EK43 (flat).
Brewing / filter
Look at the main population and the share of fines and large particles. Examples: EK43 and Ditting 804 Lab Sweet (flat; discontinued). Conicals can also work at suitable settings.
02 / TEETH
What is burr geometry?
Even flat burrs differ in tooth height, direction, length, spacing and the placement of smoother areas.
Three drawings inspired by real burrs
TOP VIEW / PHOTO-INFORMEDDrawings distinguish the broad Ditting ridges and outer teeth, dense EK43 radial flutes, and swept SSP Multi-Purpose edges observed in product photos. Exact dimensions, angles and area ratios are not measured.
Ditting 804 Lab Sweet
80 mm · CASTMahlkönig EK43
98 mm · STANDARDSSP Multi-Purpose
64 mm · MPA smooth looking area cannot automatically be called a millstone like grinding surface. Visible area is not a measure of cutting contribution.
How to read surface area
ZONE MAPLocate zones on a Ditting 804 Lab Sweet burr
Numbered positions are drawn from published burr photographs. The exact boundaries and contribution of breaking, feeding and final cutting are not manufacturer specifications.
Blind burrs: how much area do screw holes occupy?
BLIND BURR / AREAA blind burr is a flat burr mounted from the rear, leaving no fixing screw holes on its grinding face. The Compak PK100 uses 98 mm blind burrs; the Option-O LAGOM 01 Mizen XL uses 102 mm blind burrs. The uninterrupted face leaves room to extend the tooth pattern, but not every newly available square millimetre becomes a cutting edge.
Area model: annulus A = π/4 × (outer diameter² − inner diameter²). For an illustrative 98 mm OD, 50 mm inner opening and three 6 mm holes, hole area is 84.8 mm²; removing them increases same-diameter planar area by about 1.5%. Three wider 12 mm screw seats yield about 6.5%. The opening and hole dimensions are assumptions, not product measurements.
Option-O reports about 18% more effective grinding surface for its 102 mm Mizen XL blind burr versus a standard 98 mm burr: the larger diameter and missing face holes act together. Assuming the same 50 mm opening and three 12 mm screw seats gives about 18.5% in a planar model. Option-O does not publish the effective-area boundary or hole dimensions, so this is an illustration, not independent verification of its 18% figure. Compak does not state a percentage for the PK100.
03 / MATERIAL
Material, wear and heat
Read material alongside geometry, alignment, speed and cooling.
Steel / cast steel
01Machining, heat treatment and coating change wear resistance and edge retention. Ditting 804 Lab Sweet uses cast steel burrs.
Ceramic
02Hardness and wear resistance may help, while impact damage also matters. A taste ranking against metal at identical geometry is unverified.
Continuous grinding and temperature
03Studies link bean temperature before grinding to particle distribution and espresso composition. A causal link from burr material to quality loss during continuous grinding remains unverified.
Official material terms by maker and model
MAKER DATACast steel and special steel describe the base; titanium coating and Red Speed describe surface treatment. A “titanium burr” need not be solid titanium.
Ditting804 Lab Sweet
BASE MATERIAL
프리미엄 주강 / premium cast steel
SURFACE
↗명시 없음 / not specified
MahlkönigEK43 standard
BASE MATERIAL
경화 프리미엄 주강 / hardened premium cast steel
SURFACE
↗글라스 비드 블라스트 / glass bead blasted
AnfimLuna
BASE MATERIAL
특수강 / special steel; 본문: 경화강 / hardened steel
SURFACE
↗명시 없음 / not specified
AnfimPratica
BASE MATERIAL
경화강 / hardened steel
SURFACE
↗명시 없음 / not specified
AnfimSP II+
BASE MATERIAL
모재 미공개 / base alloy not stated
SURFACE
↗티타늄 코팅 / titanium coated
SSPCustom burrs
BASE MATERIAL
모델별 확인 필요 / model specific
SURFACE
↗Red Speed · Silver Knight · TiCN · DLC · ZrN
TiCN = titanium carbonitride / 탄질화티타늄 · DLC = diamond-like carbon / 다이아몬드상 탄소 · ZrN = zirconium nitride / 질화지르코늄. Red Speed and Silver Knight are SSP coating trade names.
SSP lists coating names. Its service page does not specify the exact Red Speed chemistry or base alloy for each burr, so neither is inferred here.
Working hypothesis / Recording burr and ground coffee temperature alongside shot time during repeated grinding could help test changes in repeatability.
04 / CONTROL
Tools for controlling distribution
Sieving selectively separates particle groups after grinding. Especially for espresso, evaluate flow and taste before removing fines.
KRUVE Sifter
MICRON SIEVESTwo interchangeable micron sieves separate fines, middle and large particle groups.
Manufacturer / paper ↗Wave Prism Sifter
KOREA / SCREENA Korean developed sieving tool with a transparent vessel and interchangeable screens.
Manufacturer / paper ↗Sieving changes both the dose and the mass of each particle group. Record the separated mass, recipe and brewing result.
05 / REFERENCES
Sources
Educational drawings · not product measurements
- Scientific Reports · fines & espresso ↗
- Scientific Reports · bean temperature ↗
- Ditting · 804 Lab Sweet ↗
- Mahlkönig · EK43 S ↗
- Niche · Zero ↗
- SSP Grinding Solution ↗
- KRUVE Sifter ↗
- Wave Prism Sifter ↗
Quick answers
Do flat burrs always produce fewer fines than conical burrs?
No. Layout is only one variable. Tooth geometry, beans, grind target, alignment and measurement method also change the distribution. This chart is not a product measurement.
What does the same grind setting mean?
Dial numbers on different grinders are not comparable. These example curves share an assumed median particle size (D50) near 600µm.
Are titanium coated burrs made of solid titanium?
No. Coating is a surface layer. Base material is named only when the maker states it.