Dry crushing is the most traditional method and is popular in microbreweries. The distance of the rolls can generally be adjusted according to the crushability and the capacity of the crusher, and the crushed malt can be kept in the hopper.
Dry crushers are easy to operate, but have some disadvantages in use. Most notably, the crushability is difficult to control due to variations in the moisture content of the malt. Therefore, it is generally best to keep the moisture content of malt at 6-8%. If it exceeds 8%, the malt can easily be ground into flakes instead of powder; however, if the moisture content is below 6%, the hulls of barley can easily be ground into powder, which is detrimental to a good grain bed for wort fermentation.
Advantages of dry crushing.
(1). Lower requirements for crushers, easy to operate
(2). The current consumption is smaller
(3). The drier the endosperm is, the better the grinding effect is.
(4). Drier milled malt helps to extend storage time
(5). The epidermis and power of barley can be separated and fed separately.
Disadvantages of dry milling
(1). The milling chamber should preferably be separate from the brewing chamber, and hoppers and silos etc. can create a higher budget.
(2). The skin of barley is easily broken
(3). There is more dust and danger of explosion