More About Barley Than You Actually Wanted to Know

Posted on February 20, 2016March 11, 2016 by The Wolf

February is the Whole Grain Council's Barley Month. Seriously. Barley has a month. We couldn't make this stuff up. So grab a beer, pull up a chair, and let's talk about this unsung hero. Barley, as we know, is the main ingredient (aside from water) in beer. But why barley? Why not rice, or corn, or oats? It comes down to a magical thing called diastatic power, but to explain what that is, we need to (write a whole dissertation), oops, I mean, back up a step, right to the beginning of a plant's life. To oversimplify a bit, a seed (such as a barley kernel) is a dormant packet that contains starch and a plant embryo. Yes, there are other types of molecules (like protein) in there too, but let's keep this simple. The energy contained in the starch will sustain the baby plant until it has grown enough to make its own energy from sunlight, and pull water and nutrients out of the soil.

(Nerd alert!)To begin the germination process, a seed has to convert the large, bulky starch molecules into smaller, usable sugar molecules. This starch-to-sugar conversion process is performed by water-activated enzymes, which is why seeds don't germinate unless conditions are wet enough. These special enzymes are called alpha amylase and beta amylase. Most types of grain kernels produce just enough amylase to convert their own starch content, without much to spare. Barley is different. Barley makes extra amylase; each kernel can take care of its own needs, and has some leftover. Analogy (sorry it's not a great analogy, but it'll work): think of a scout troop on a hike. Each child (hopefully) carries enough water for himself, but the Leader always carries extra. This ability to convert extra starch into sugar is what gives (our Scout Leader) barley its high diastatic power. But why is the ability to convert extra starch into sugar so important? I'm getting there. Bear with me; don't get bored yet. First, I need to explain the germination and malting processes a little bit. (Feel free to grab another beer.)

A maltster (I love that word!) takes barley grain; wets it; stirs it; and dries it. Sounds easy. Nope. The job of malting is actually about the trick of halting the germination process at just the right time. At the beginning of germination, amylase levels are relatively low; one of the first things a growing kernel does is make more amylase so that it can unlock the energy to grow rapidly. The most important aspect of malting is to stop the germination process when amylase levels are highest, but before the amylase has much time to convert starch into sugar. If a germinated kernel is allowed to grow too long, it converts all of its stored starch into sugar, and burns through that sugar rapidly as it grows into a baby barley plant. Baby barley plants, sadly, are useless to brewers. Or, if a nervous maltster stops the process too early, the amylase levels never get high enough to convert all of the starch in the kernel. If, after the step in the brewing process called mashing, the energy in the grain is still starchy, instead of sugary, yeast is unable to ferment it (a horrifying scenario that will result in something like porridge!). The important thing to remember is that barley has the potential to achieve high diastatic power, but only if it has been properly malted. So diastatic power... what's the point? I'm finally ready to tell you. Without it, we wouldn't have much variety in our types of beer. Variety, as we know, is the spice of life.

The grain portion of any beer recipe includes two general categories of malt- Base Malt and Specialty Malt. Base malts (examples: pale malt, Pilsner malt) make up a very large portion of the total amount of grain needed for a recipe. These malts have only undergone the malting process described above and maintain their high diastatic power. Base malts are the workhorses that are going to help the Specialty Malts achieve their greatest fermentability potential. Specialty Malts, for the most part, have zero diastatic power because they've been roasted at high temperatures, which denature the amylase enzymes. Specialty malt has been roasted to caramelize the bit of sugar it contains, resulting in the red/brown/black malts that give color and flavor to many delicious varieties of beer. They are responsible for the rainbow of variations of color, body, flavor, and even mouthfeel that are available to a brewer. Even slight differences in roasting temperature or duration result in specialty malts with different qualities. (Think about the fine art of coffee roasting, and the variety of roasts available.) Brewers are able to achieve a wide variety of beer styles thanks to the fact that barley (base malt) has enough extra amylase to convert flavorful specialty malts' starch into sugars. (Go grab another beer. You deserve it.) Trivia: Which grain do you think has the second-best diastatic ability? Think about beer styles for a second and which types of grain you've seen involved... and the answer is... drumroll... Wheat.