The process that puts the MALT in malt whisky
A characteristic difference between Scotch MALT whisky and some other forms of whiskey is that it is distilled from barley that has been forced into sprouting in a process called malting (or the maltings).
At Springbank, this whole multi-step process is still done 100% on site by hand. Highland Park, Bowmore, Laphroaig, Kilchoman, the BenRiach, and the Balvenie also maintain traditional malting floors where they malt some of their own barley (and other distilleries have plans to re-open malting floors for some in-house maltings). It’s backbreaking work — at least for someone usually writing and talking. The repetitive strain injury one can develop working the maltings is called “monkey shoulder.” Think shoveling snow all day, every day. Even at Springbank, where every bottle of Scotch comes from barley that’s been malted in-house, these days the maltsters rotate through other production jobs. But it’s still hard work.
The barley grains are loaded into the steep, a large tank that is filled with water. There the barley is soaked, absorbing water so the grain thinks it’s time to start germinating.
The steep is drained and filled more than once, and monitored to make sure all the grains are evenly soaked. After about 36 hours, it will reach a moisture content of 40-48%.
After the grain is drained of water, it is spread out on the floor to a depth of 3-5 inches/8-12 centimeters. It’s been tricked into thinking it’s springtime and will begin to send out shoots and rootlets. These produce enzymes that breakdown the carbohydrates stored in the barley, making it available for yeast to turn into alcohol at the later fermentation stage.
As it sprouts, the grain is grubbed (raked) a few times a day to ensure that the roots and shoots don’t become matted and that temperature remains even throughout.
Temperature and humidity are regulated mechanically at more industrial malting facilities. Many traditional floor maltings depend upon the heat from the germination process to keep the grains warming and drying.
Germination can take place in the ground at temperatures as low as 40 degrees Fahrenheit/4 degrees Celsius, but on the malting floor, the germination temperature is 60-68F/16-20C.
After 4-6 days, the barley is ready to leave the malting floor. Enzymes have done their work changing inaccessible starches into accessible sugars. With the addition of yeast, these sugars are what will be converted into alcohol.