milling
Milling
Crack the malt kernel so water can reach its starch, while leaving the husks intact enough to form a filter bed during lautering.
What is actually happening
Roller mills crush the kernel between rollers set to a controlled gap, splitting the husk and crumbling the endosperm inside it. Hammer mills pulverise instead, and require a mash filter rather than a grain bed.
The gap setting is a direct trade-off. Finer crush exposes more starch and raises extract efficiency; it also produces more fine material, which compacts the bed and slows or stops the run-off.
What goes wrong here
Risks rather than certainties. This step does not cause these faults; getting it wrong can.
- Astringency — A drying, tannic harshness from over-extracted grain husk — the classic sign of sparging too hot, too long or at too high a pH.
Related steps and concepts
- Mashing — What the grist goes into next.
- Lautering — The step the crush has to be set for.
- Husk — What milling must preserve.
- Stuck sparge — What too fine a crush causes.
Last reviewed 2026-08-16.