Connecting the campus to the community
By Dr. Paul J. Pope
You are probably familiar with the four main ingredients used to make beer; malt, hops, water, and yeast. Combinations of these ingredients are used to brew a myriad of different beer styles. In fact, only a few beer styles are reliant on adjuncts, fruits, or spices to define the style. The vast majority of beer styles only use these four ingredients. For this article I will be focusing exclusively on malt.
The most common cereal grains used in brewing throughout the world, in order of use, are barley, wheat, oats, and rye. Other grains and adjuncts are commonly used, but make up very small portions of the grain bill such as corn, buckwheat, and rice. Barley, wheat, oats, rye, and rice are all part of the grass family. However, these grains are incredibly difficult to use strait out of the field, and they will not yield much to brew with. Some beer style do use un-malted grains, but these are in a very small minority of beer styles. Malting greatly increases what can be extracted to make beer.
Malting grains is essentially tricking the grains into germination then drying and kilning them. First the grains are soaked in warm water until they begin to grow tiny rootlets and an acrospire. The acrospire will begin to grow, but before it gets much longer than the length of the grain (the seed of the grain) the germination is arrested by drying. What has happened to the grain is the germination has created a lot of starch as a food source for the growing plant. This increase in starch is known as modification. The amount of starch in the grain is significantly higher than before germination, this is called modification.
After the grain is dried it is kilned (exposed to higher heat than drying). To create different styles and darker grains the maltster kilns the malt at different temperatures and for differing lengths of time to produce different types of malt. For comparison, Pilsner or pale ale malt, light colored base malts, uses lower heats for shorter periods of time. This preserves the enzymes in the malt that can be used during the mash to convert all that lovely starch into sugars the yeast can ferment. The color rating of malt is called the Lovibond scale. Pilsner malt usually ranges between 1.5-2 L and pale ale range is 2.5-4 L. These malts have enough enzymes to convert all its starch to sugar with enough left over for adjuncts and other highly roasted grains.
Roasted and toasted grains are much darker malts than base malts because they are kilned for longer and at higher temperatures. A toasted malt will likely be kilned to 15-50 L. A roasted malt, often used in porters and stouts, will be kilned to between 400-500 L. Toasted malts have had most of their enzymes denatured from the higher heats and the longer roasting period. Highly kilned malts, sometimes called black malt, will have no available enzymes to convert its sugars. These malts often resemble roasted coffee in their look and flavor more than beer malt. The more of these grains used the more the brewer needs highly enzymatic base malts to insure full conversion in their mash.
Crystal malts (or caramel malts) are made a bit different. Rather than drying after the germination process, when the grain is still quite moist, the maltster cooks (or stews) the grain. This converts the starches to sugar inside the grain and then caramelizes or crystalizes (nearly interchangeable terminology) to create higher melanoidens in the malt, the yeast can’t easily consume. This is used to give body, increased color, and caramel flavors to beer. Because the sugars are already accessible, these grains don’t need to be mashed, but merely soaked in hot water to release their sugars, after being milled of course.
Combinations of these grains, in varying amounts, is used to create almost any style of beer. A brewer will create their grain bill (the mix of various grains to be mashed), then mill them together, they soak the crushed grains in hot water to convert the starch into sugars for the yeast to consume. It is said that yeast is the soul of beer. However, malt is beer’s backbone.