Malted barley is spread upon floors, with small orifices, to a depth of a foot or 15 inches, so that the hot air and smoke coming from the furnace below through the small openings in the floor pass up through the malt and escape through the chimney in the roof.

The malt is turned frequently during drying. Great care must be taken not to raise the temperature of the malt too high otherwise the activity of the ferment, that is, the diastase will be lessened.

The malt is dried until the percentage of water is reduced to a small amount, not to exceed 4 percent. Malt is considered better if it be kept stored for a time before it is subjected to manufacture.

Scotch whisky is made solely from barley malt; no other grain nor unmalted barley being used. It is therefore a type of a pure malt whisky.