Spirit safe IV

Spirit safe IV

The spirit, the "heart" that emerges from the spirit still via the condenser and spirit safe goes into the spirit receiver to be put in casks. At this stage it is about 70% alcohol by volume. The foreshots and the feints, the unwanted "head" and "tail" go back to the low wines and feints receiver to mix with the next batch of low wines from the wash still before being returned for another trip through the spirit still.
The physical and chemical processes taking place within the still are very complex and not all are totally understood. What is clear, however, is that a number of different factors have an effect on the quality and taste of the malt whisky that the spirit eventually becomes. One important factor is the material from which stills are made, copper. This acts as a catalyst and promotes a number of chemical reactions within the still: indeed, the copper of the stills is slowly consumed by the process, and stills will regularly have thin sections replaced.