The task of modifying grain during malting lies solely with the maltster, who harnesses nature and natural processes to create the essence of every beer. Grain modification, along with enzyme creation, is the primary objective of malting cereal grain. While the brewer or distiller uses some of these grain enzymes in the mash, others are utilized by the maltster to modify the grain. The purpose of grain modification is to make the starch and proteins within each kernel accessible, as these starches ultimately become the crucial ingredient for beer production – sugar.
Modification begins during the soaking of raw cereal grain. Towards the end of soaking, the maltster uses the moisture content of the kernels as an indication that germination has commenced. At this point, hormones trigger the production of enzymes. Around 30-50 percent moisture, depending on the grain variety, signals the maltster that it is time to conclude soaking and initiate germination. Now that the dormant kernels are awakened and beginning to sprout, the enzymes begin to modify the grain. During germination, certain early-forming enzymes break down the cell wall structure of the kernel, which encapsulates starches and proteins. This breakdown of the cell wall compounds and the release of starches and proteins is referred to as modification.
During modification, enzymes degrade and dissolve the cell wall components known as beta glucans and pentosans. By breaking down these cell wall components, the starches and proteins become accessible. Xylanases enzymes break down the pentosans, while glucanases enzymes break down the beta glucans. This modification is crucial for brewing a delicious craft beer, underscoring the importance of sourcing quality malt for the creation of top-notch craft beer.
An additional benefit of breaking down the cell wall molecules is achieving a smooth lautering process for brewers. These molecules can be highly viscous, and excessive levels of beta-glucan in the final malt can lead to difficulties in lautering and extracting. Maltsters and brewers consider the beta-glucan levels in malt as an indicator of its quality and level of modification.
Extreme heat or cold during soaking and germination, as well as other climatic factors, can disrupt the proper sequence of events within a grain kernel, resulting in undegraded beta glucans, pentosans, and proteins. This can adversely affect lautering during brewing. It is crucial for maltsters to effectively control these factors to produce high-quality malt.
Maltsters today benefit from advancements in malting techniques and barley breeding, enabling them to create an even better and more flavorful product. Craft brewers in the present day reap the rewards of these achievements, continually producing higher-quality beers. Cheers!