Simulate how the grinder shapes flavour

Which grinder suits your taste?

A grinder is something you see in the kitchen — and taste in the cup. Set burr type, burr cut, speed, burr size and alignment and watch where body, sweetness, fruit and clarity move. If you like it, you're right.

How to read this tool

The sliders: burr type (conical or flat), burr cut (classic or modern), speed in rpm, burr size in mm, alignment.

The results: EstimateIndicators from 0 to 100 out of our model — not measured values. They show the direction, not the taste.

The basis: experience from consultations and the café, the direction from studies on particle size distribution. No guarantee — details right underneath the tool.

In more detail: sliders, model and sources

The sliders in detail: Burr type conical (a cone inside a cone) or flat (two parallel discs). Burr cut classic or modern — the geometry of the cutting edges. Speed 100–2000 rpm; if you choose «conical», the tool limits it to 100–500 rpm, because conical burr sets mostly work in that range. Burr size 38–98 mm is the diameter of the burr set. Alignment (factory, good, perfect) describes how exactly parallel the two burrs sit to each other.

The results in detail: EstimateBody, sweetness, fruitiness, clarity, fines and uniformity (homogeneity) are indicators from 0 to 100 — the model moves between 5 and 95. All six come out of one formula we built from experience: estimated, not measured. «Fines» means the share of dust (particles under 100 µm), «uniformity» how closely the particle sizes sit together. The indicator «Fines 62» does not mean that 62 % of your grounds are fines — the figure names the estimated share by weight separately.

The curve is schematic: The figure «Animation 1 · Particle sizes in the grounds» shows particle size in micrometres on a logarithmic axis (each step ten times larger) and the share upwards without a numeric scale. The curve is drawn from the indicators fines and uniformity and the chosen burr cut — it is not a measured distribution. Position of the humps: fines around 45 µm (Corrochano et al. 2015: 40–50 µm), main particle around 330 µm (Uman et al. 2016: modal values 257–282 µm depending on origin). The toggle «by weight / by count» converts the same curve: one 330 µm particle weighs as much as around 400 fines of 45 µm — which is why by count almost all particles are fines, while by weight they are a minority.

A correction: The old version of this figure showed three humps for «classic» and a single narrow curve for «modern». Neither is right: measured espresso distributions always have a fines hump and a main-particle hump (Uman et al. 2016; Smrke, Eiermann & Yeretzian 2024). «Unimodal» is a marketing word — «fines-reduced» is more accurate. More on our page Bimodal vs. unimodal particle size distribution. Also changed: speed no longer increases the share of fines in the model; there is no documented general relationship (see RPM profiling). That higher speed brings more body and lower speed more aroma remains in the model as experience from our cafés — In-house tasting judged by tasting, not measured.

The basis — and a second correction: The old simulator said «measurement data: Gagné/ZHAW analysis, 24 grinders». Those were two different things under one name. The dataset with around two dozen measured grinders comes from Jonathan Gagné (coffeeadastra.com) — a careful, openly documented Community measurement, not peer-reviewed. The work of the ZHAW is something else: Smrke, Eiermann & Yeretzian 2024, «The role of fines in espresso extraction dynamics», Scientific Reports 14, 5612 — Peer-reviewed, but about the role of fines in espresso extraction and not a comparison of 24 grinders. The ZHAW gives the share of fines (under 100 µm) as 25–35 % for conical burrs, 15–30 % for flat burrs, 5–15 % for roller mills (talk by Smrke, World of Coffee 2024; Eiermann & Smrke 2020). The concept of particle size distribution itself goes back to Uman et al. 2016, Scientific Reports 6, 24483. From these works we took the direction, not the numbers: what the tool outputs is our model calculation — not an evaluation of these datasets and not a measurement of any particular grinder.

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No guarantee

This is a simulator. It works with a simplified model and shows you how things relate — no measured values and no assurance. What ends up in your cup depends on your machine, your water, your beans and the way you work.

Our recommendations are based on experience from consultations, courses and the showroom. They are non-binding and come with no guarantee. We accept no liability for damage arising from their use. When in doubt, what your manufacturer writes in the user manual applies.

EstimateThe six bars and the curve above are calculated values from our model, not a measurement of any grinder. They show you the direction burr type, burr cut, speed, burr size and alignment pull in — not what a particle analyser would show for your burr set.

What to take away from the tool

Uniform grounds are the prerequisite for choosing a fine grind size and extracting slowly and steadily — that is how we work in our cafés. Dust (fines) brings body, but too much of it masks aromas. A modern, fines-reduced burr cut makes the cup clearer and fruitier, a classic one rounder and fuller. Both can taste great; this is our way, but not the only one.

If you are looking for a grinder, the measurable things will get you further: uniformity, retention, handling and how finely the grind size can be adjusted. The burr type alone says little about body. Questions about it are answered by Jackson, our AI advisor — he asks about look, kitchen and moment first, then about the technology.