The malt grist is fed into the 'mash tun' where it is combined with a carefully measured quantity of hot water. This completes the conversion of dextrin into maltose and produces a fermentable solution of the malt sugars caled 'wort' or 'worts'. Again, after several washings to draw out the malt, the solid residue or 'draff' is removed and sold as cattle food. The worts are held in a receiver called an 'underback'. This must be cooled to prevent unwanted decomposition of the maltose and to allow yeast to be introduced. The cooled worts are injected with yeast and the fermented in a further tank or tanks called 'washbacks'. Thirty-six hours or thereabouts of sometimes violent fermentation produces a weakly alcoholic (10 degrees or thereabouts) clear liquid called 'wash', which will now be distilled