Milling is the physical crushing of malt kernels into smaller particles in preparation for mashing and lautering. The various milling processes need to be manipulated carefully to find a balance between a grind that is too fine and one that is too coarse.
![The Oxford Companion to Beer Definition of milling (1) The Oxford Companion to Beer Definition of milling (1)](https://i0.wp.com/storage.googleapis.com/cbb-oxford-assets/images/acref.9780195367133.graphic.013009.jpg)
The grist mill at the Hook Norton Brewery in Oxfordshire, England, dates from 1899 and is powered by a steam engine from the same year. cath harries
Mill settings, therefore, are always a balance between two incompatible requirements, the maximization of yield and the practical workflow in a brewhouse. At the same time, they have an enormous influence on the biochemical transformations in the mash tun, on brewhouse yields, on the composition and the quality of the wort, and finally on the taste of the beer. A fine, flour-like powder—although the most desirable grind for rapid and optimal enzymatic conversions of all grist components—might also leach too many undesirable substances into the wort and beer, such as silicates, lipids, husk-derived tannins, and large-molecular proteins, which can cause deposits, hazes, and a shorter shelf life. Given the variability of the grist from one harvest year to the next, from one vendor to the next, and between the grain bills for different recipes, milling is as much of a fine art as are the other parts of the brewhouse process.
Bibliography
European Brewery Convention (EBC). Milling, manual of good practice. Nuremberg, Germany: Hans Carl Verlag, 1999.