The process by which barley is converted into a usable form for brewing is called malting (Figure 3). Malting originated nearly 6,000 years ago, and although the process has not changed, the technology to carry out that process has advanced drastically over the years. When barley is malted, it is steeped or intermittently immersed in water for two to three days, which allows the grain to sprout. Sprouting the grain generates the enzymes necessary to convert starches into sugars during brewing. Once the grain has reached the optimum moisture level, it is transferred to the malting or germination floor, where it is constantly turned over a four to five-day period to ensure consistent germination. Automated malting facilities will use a pneumatic plant in lieu of a germination floor for this stage. The product, at this point known as green malt, is then kiln-dried, which ends germination. The length of the kilning period depends on the desired flavor and color of the malt product.
Options for malting in Michigan are limited but are expected to expand as the demand for local ingredients increases throughout the craft brewing industry. Access to high-quality barley is a major limiting factor to malthouse growth in-state. Quality barley grain is necessary to ensure quality malt. Following best management practices for controlling both disease and fertility in your stand is critical.
Malts & Malting by Dennis Briggs, 1998
The Craft Maltster’s Handbook by Dave Thomas, 2015
Malt by John Mallett, 2014