Search: hammer mill

Malt is ground between two horizontally positioned, grooved discs. The lower disc is driven by an electric motor and rotates at approx. 1500 rpm; the upper disc is fixed and therefore does not move. During the milling process, the malt migrates from the center of the discs to the outer edge, where the grist falls through an outlet spout into a grist beaker.

The gap between the discs can be adjusted by turning a socket head screw on a calibrated ring bearing scale markings. The scale on the calibrated ring ranges from 0 to 20, with each scale division corresponding to a gap between the discs of 0.10 mm. Each scale division is subdivided into five smaller divisions; each of the smaller marks is equivalent to 0.02 mm. Two gap adjusting rings ensure reproducible mill settings.

The respective constituents of hops are not uniformly distributed throughout the cones. The aroma compounds and bitter substances are found in the lupulin glands inside the cone, adhering to the cone bracteoles near the strig. The polyphenols, on the other hand, are found in the bracts, bracteoles and stems. In order to reliably analyze the constituents of hop cones, homogenization of the sample is required. For this purpose, the cones are ground and the sample is divided.

The moisture content is determined by means of the loss in mass during a standardized drying process. For this purpose, the spent grain is dried at a defined temperature over a set time in an electrically heated air drying oven. The moisture content is determined by the difference in weight before and after drying.

If the barley possesses a moisture content of more than 17 % w/w, the whole kernels shold be dried prior to grinding them and determining the moisture content in the (coarsely ground) spent grain. The moisture content of the finely ground spent grain is subsequently determined and the total moisture content calculated from both values.