01Roller mill or burr grinder
Industrial lines usually grind with pairs of corrugated rollers in stages; large flat or conical burr grinders suit smaller batches. Rollers give a narrower particle spread. Ask which principle, how many stages, and why for your grind.
02Capacity at your grind size
One listing gave 200 to 1,000 kg an hour across a whole model range. Ask for the rate on one model at your target particle size, measured on roasted coffee.
03Heat and cooling
Grinding warms the coffee and drives off aroma. Ask whether the rollers are water cooled and what coffee temperature at the outlet was measured.
04Roller wear and re-cutting
Corrugations wear and the grind drifts coarser. Ask the roller material, expected tonnes before re-cutting, and whether re-cutting is possible in Europe.
05Normalising and dust
Some mills add a mixer after the rollers to even out density. Fine coffee dust in an enclosed space needs extraction; ask the airflow the machine expects.