Lesson 6 - Milling Technology

From our milling studies thus far, we have gained a good understanding of how malt and adjuncts are prepared for the mill and what we need our mill to achieve. In this lesson, we meet the equipment that we will use to do the job. We will also get a good idea of how to select the right mill for our brewhouse and beer.

We can divide the technology used to mill into two, on the basis of the condition of the malt when it is milled. If we have added a significant amount of water to the malt, and the grist is mashed in immediately, we call it wet milling. If not, we call it dry milling. We have used the term ‘significant’ because we class conditioned milling, where water or steam has been used to moisten the husk before the mill in a conditioning screw, as dry milling. This is because the moisture level of the malt is only increased by less than 2.5%, so it is effectively still ‘dry’ when milled and is stored in a grist case before mashing in.  

Wet milling is undertaken in a wet steep mill, underwater disc mill, or a steep conditioned mill. With dry milling, a hammer mill or dry roller mill (with or without conditioning) is used.

Mills are an integral part of the brewhouse and choosing the right mill depends on the processes and equipment used after it, as well as the grain it is required to process.

In this lesson, we will cover the design and operational characteristics of several mill types. We will also explore how the required grist and wort separation systems are critical to their selection.