During this time the grain becomes soft and sticky and starts to germinate. Small sprouts grow from the kernels, enzymes are released, and the starch in the grain is converted into maltose (a kind of sugar).
Next, the grains are spread out on the malting floor to germinate; they’re turned regularly to prevent overheating. A handful of distilleries still turn the germinating malt manually by using a wooden spade (shiel) or a motorised device resembling a small lawn mower.
Germination takes about a week during which the “green malt” becomes saturated with natural sugars that will produce alcohol during distillation. Because this traditional process is quite labour-intensive, nowadays it is largely mechanised and centralised. The majority of the barley comes from large commercial malting plants in Scotland that use centrifuges for the malting process.
To stop germination, the barley needs to be dried. That happens in a drying oven or kiln, using hot air. The chimney of many Scottish kilns has a pagoda-shaped fan, an innovation of architect Charles Doig in the 19th century.
Nowadays most distilleries buy their malted barley from large commercial maltings that produce their malt according to precise specifications. However, the pagodas on former kilns can be seen throughout Scotland.
Our whisky Q&A is provided courtesy of SMWS ambassador Hans Offringa’s A Field Guide to Whisky: An expert compendium to take your passion and knowledge to the next level