The first step is to take clean grain that has been filtered to remove debris, like straw, chaff and broken kernels, and steep it in water. During steeping, grain is alternately soaked in water and drained until the moisture content reaches 40 percent to 45 percent. Air may be bubbled through the soaking grain to keep things stirred up.
During steeping, rootlets start growing from kernels, which at this stage are called chitted barley. Once a high enough percentage of chitted kernels exist, maltsters move on to the next step.
Chitted barley is moved from the steeping tank for the “steep out.” The germination that began in the steep tank continues during this stage. Humidified, temperature-controlled air is blown through the grains while turners keep rootlets from growing together.
The water that was absorbed by the grain causes existing enzymes to activate and creates new enzymes. Some of the enzymes produced during this stage will break down starches during brewing. Enzymes also break down the proteins and carbohydrates that protect the kernel's starch granules. Once this takes place, starch granules can be turned into malt sugars, which are key elements in the taste and color of beer.
The final stage of malting is drying, which is sometimes called kilning. If grains were allowed to continue to germinate, the kernel would use up all the starch needed to create sugars later in the process. Most malts are dried in a kiln at temperatures between 180 and 190 degrees Fahrenheit for two to four hours. The flavor and color of malts are determined by the heat and the amount of time spent drying. Specialty malts may spend more time in a kiln or be dried at a higher temperature.
Once the malting process is complete, a mill is used to break up the grain without destroying the husks. The mill should just break the grain into fragments while leaving the husk mostly intact, since husks are normally used as a fiber bed through which to drain unfermented beer.
Our next post will look at mashing, the next step in brewing.