Malting: Enzyme Creation
Good malt makes good beer, and good beer makes everyone happy. I don't think it can be overstated how important malt is in making your favorite craft beer. Malt is the foundation that all other beer ingredients build on. During the act of malting cereal grains, there are two primary goals, enzyme creation, and modification. These two variables along with other factors, like moisture and color, are used to judge malt quality. The maltster will focus on these two primary goals to create a consistent and predictable product for beer production.
Malt starts as a cereal grain, usually barley, that is steeped then germinated and kilned. Germination is where the grain begins to change into a fermentable raw ingredient, perfect for beer brewing or spirit distillation. At this time every kernel of grain will create natural enzymes, some of those enzymes will then break down (or "modify") the cell walls located around the kernel's endosperm. Both processes are necessary for malt to be predictable, effective, and desired.
All enzymes are created during the germination stage of the malting process. When a barley seed, or "kernel", comes to life it creates enzymes to help break down the stored starches, proteins, and fats - releasing those resources for growth. The maltster harnesses this natural process to secure those resources for the brewer or distiller. Enzymes are so important because they break up everything inside the embryo's food storage vessel, the endosperm. They degrade complex molecules into simple molecules, making the resources available for the barley embryo. Or if you're a brewer, for your yeast.
Enzyme formation starts with the uptake of water, encouraging the release of a hormone called gibberellic acid - this hormone promotes the development of enzymes. The germination stage will go for 5-7 days, depending on the malting system and grain variety. The enzymes are made during days 2, 3, and 4.
Every cereal grain variety has starch degrading enzymes, cell wall degrading enzymes, protein degrading enzymes, fat degrading enzymes, and phosphoric acid splitting enzymes. Starch degrading enzymes, or amylases, are essential to the end quality and effectiveness of malt. During a brewer's mash, these amylases degrade the complex starches into simple sugars that yeast can later eat and create alcohol and CO2. Alpha-amylase and beta-amylase are two examples of these starch degrading enzymes.
The maltster's goal is to create the proper kind of enzymes along with the proper number of enzymes needed to fit the profile of a malt style. The number of enzymes formed depends on many factors such as barley varietal properties, kernel size, water and air content in the germinating malt, and temperature of germination (cooler being better for enzyme creation). So, for proper germination and enzyme creation, the maltster controls moisture, aeration, and temperature. If any of these wanders too far to the extreme the maltster can end up with either hard non-fermentable kernels or with growing barley plants.
Malting sets up the brewer with the resources they need to make our most cherished craft beers. The brewer then activates those resources in a mash. The maltster's job is not only to create plenty of enzymes but also to "modify" the grain, making the starches and proteins available.
In my next Original Craft Beer Club blog, we'll explore the process of modification. Until then sit back, drink up, and ponder the science that is beer. Cheers!
Kunze, Wolfgang. Technology: Brewing & Malting. 5th ed. Berlin: VLB, 2014.
Mallett, John. Malt: A Practical Guild from Field to Brewhouse. Boulder: Brewers Publications, 2014.