Part of the craft beer brewing process often involves modified grains. Whether you are a seasoned professional, a budding amateur, or just a craft brew connoisseur, understanding the grain modification process will enhance your knowledge and your craft beer experience. Toward that end, the team at Cheers All offers a brief explanation of grain modification as it applies to craft beer.
What Is Grain Modification?
Modification, also known as enzymatic conversion, degradation, and solution, refers to the chemical breakdown of compounds that reside naturally in grain. For craft brewers, the substances in grain that matter are starches and proteins. As they occur in nature, both starches and protein molecules are much too complex to work for brewing beer. Starches are carbohydrates that occur in the form of long chains or branched tree-like cluster formations. Carbohydrates can have wide variations in complexity, from highly complex structures such as wood to less complex structures called sugars. Proteins are nitrogen-based compounds that also come in large and small molecular form. When brewing beer, grain modification may vary widely depending on the degree to which starches are converted to malt sugars as well as the degree to which long protein chains are split up into smaller ones, such as yeast nutrients called amino acids.
Modification by the Maltster
Grain modification is both a science and an art performed by the maltster. Modification along with enzyme creation are the two primary goals of malting cereal grain. The brewer or distiller will use some of those grain enzymes in a mash, while other enzymes are used by the maltster to modify the grain.
Steeping raw cereal grain in where grain modification begins. The maltster watches the water content of the kernels toward the end of the steeping process to determine when germination has started, and enzymes have started being created. Once the raw dormant kernels are awake and beginning to grow, the enzymes will begin to modify the grain. During germination some of the early enzymes created will break down the kernel’s cell wall matrix, which locks up starches and proteins. All of this leads to modification of the grain.
During the modification process the kernels are counted in six categories of increasing modification percentages (0% to 5%; 5% to 25%; 25% to 50%; 50% to 75%; and 75% to 100%). The maltster will look for a modification level that suits the beer being made and the brewing technique employed. Single-temperature infusion mashes tend to require malts with high modification percentages, but brewers employing temperature-programmed mashes can use less modified malts and those using decoction can use malts that other brewers would find under-modified.
The maltster must carefully watch the entire grain modification process because extreme heat or cold during the steeping and/or germination processes or other climatic factors can destroy the proper chain of events in a kernel of grain. Ultimately grain modification is yet another delicate step in the process of brewing an excellent craft beer.
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