Malt- Whisk(e)y’s Heart of Gold
Malted Barley
Having worked in a malthouse, I was often asked questions about malt and its use in whiskey. Sadly, most of the questions revolved around,
“But malt is for beer, how are you making whiskey from it?”
While it is entirely possible that the majority of the time this question came up because Northeast Ohio isn’t exactly known for whiskey, but has a fairly robust craft beer industry, and those asking the question were not well versed in whiskey other than Jack Daniels, I feel even amongst the more educated, there is a lot of unknowns about malt. What is malt? How is it made? Why is it important in whiskey? We’ll explore and answer all of these questions.
Malt is simply a cereal grain that has been allowed to germinate up until the point that its endosperm has been converted into starch and has developed alpha amylase enzymes. Once that conversion has happened, the germination stage is stopped, the grain is dried or withered, and then roasted or kilned for flavor and color development. Typically, the grain chosen for malting is barley because it has the most potential for the highest enzyme content needed to convert the starch of other grains into sugar, when mixed with hot water during the mashing process. Barley is also unique amongst cereal grains in that it has a proper husk that can act as a filter. During mashing, this is important because it allows the hot water to flow through the grain more evenly and dissolve the starches without clumping into doughballs. Thus, it allows a distiller to be as efficient as possible and extract as much starch and sugar as possible from the grain.
But how does one make malt? Although there is indeed science involved, it’s not rocket science. In fact, you can make your own malt at home. First, raw barely seeds are steeped in water for 8-12 hours to allow the seed to soak up the moisture it needs for germination and growth. The grain is then allowed to “air rest”, that is the water is drained off so the seed can breathe and prevent drowning for another 10-12 hours before being steeped again. This final wet steep is usually only 4-6 hours just to ensure the grain hasn’t lost any moisture during the air rest. At this time, the barley will begin developing rootlets called, chit. These look like white nubs at the end of the see. When you have 90% chitting, you’re ready to move to germination.
Traditionally, germination was done on the floor of a malthouse. Twice a day, workers would either drag a special type of rake behind them, or use a shovel to stir the grain. This served two purposes:
It allowed for even growth of the grain
It broke up the rootlets and kept them from entangling and creating a large mat of grain.
During the germination, samples of barley are collected and examined to determine how much of the endosperm has been modified into starch. This is done but comparing the length of the acrospire to the length of the seed. The acrospire is the part of the seed that eventually grows out of the ground and into the stalk of the barley. When the length of the acrospire is about the same length as the seed, it is generally assumed that 100% of the endosperm has been modified. This process should take between 5 and 7 days for maximum modification and enzyme development. If the grain reaches 100% modification in a much shorter time, the maltster runs the risk of not having enough enzyme content to allow for efficient conversion of starch to sugar during the mashing process. The next step is to stop germination by drying the seed. This is called withering.
During withering, the moisture content of the seed must be reduced to less than 10%. This prevents the moisture in the seed from heating up and turning the starch into sugar before caramelizing and eventually crystalizing during kilning. This is done by blowing warm, dry air across the grain and gradually increasing the temperature in a series of steps. Once the grain has achieved the desired moisture content, it is then kilned to develop color and flavor. In Scotland, peat, a type of dirt comprised of decaying moss, was often used to fire the kiln that roasted the malt. This imparted a smoky flavor and aroma in the malt. Most modern malthouses in America use an indirect heating method that does not impart any aromas or flavors in the malt. This is because in America, most kilns were diesel or gas fueled, which left behind harsh, acrid flavors. To resolve this issue, glass tubes were instead heated by the kiln, and air was blown through them, which in turn heated up and was blown through the grain bed as an indirect way of heating.
As we’ve touched on before, malt is important to whiskey because it contains the enzymes needed by the distiller to access the starches in grain, and convert them to sugar. These sugars are necessary because they will then be consumed by yeast that convert them into alcohol. The more enzymes the malt has, the more starch can be converted into sugar, which will yield more alcohol. How much malt is used usually depends on the whiskey. Most bourbons only see 10-15% of the mash bill being comprised of malt, while some Irish and Scotch whisk(e)ys will have upwards of 50% of the mash bill containing malt, with “Single Malt” whisk(e)y being entirely made up of malted barley.
Despite being such a small grain, malt, and specifically malted barley, certain plays a large role in our beloved whisk(e)y.