Whisky Words: Draff
Draff > noun dregs or refuse.
ORIGIN Middle English: perhaps from an unrecorded Old English word related to German Traber, Traber 'husks, grains', and perhaps also to DRIVEL.
Draff is the name given to spent grain left in the mashtun after the wort has been drawn off.
Different mashtuns have different ways of dealing with the left over draff. Traditionally, this would have been a manual job (that is, a worker with a shovel) but nowadays most tuns have automated systems for this.
The draff is usually sold on as cattle feed or used in biomass burners.