MSU Equipment: Buhler Disc Mill
The mill is used to grind malted barley into two consistencies: Fine (0.2mm) and Coarse (1.0mm).
The fine grind gives a maximum value for tests performed on it, while the coarse grind better represents what a brewer would mill to.
The Buhler mill precisely grinds fine and coarse malt grists
The difference in consistency is achieved by moving the discs of the mill closer and farther apart
-0.2mm for fine grind
-1.0mm for coarse grind
Measurements performed on the fine grind:
- Diastatic Power
Measurement performed on the coarse grind:
The difference in extract values between the fine and coarse grind is a measure of the malt modification. The larger the difference, the poorer the modification.
A well modified malt will have similar extract values because the malting process has succesfully broken down the barley grain's cell walls and protein matrix, exposing the starch granules... more starch = more sugar = more extract.
In poorly modified malts the starch granules remain more enclosed by protein and cell wall requiring the mechanical action of grinding the malt more finely to expose them. Therefore you see a higher extract value in the fine grind than in the coarse grind.