What is a Whisky Pot Still?
The original device whereby liquids were distilled. It usually consists of a vessel – the pot – in which wine or another fermented liquid is put. The pot is heated and the vapour given off is conveyed from the pot through a long pipe, the ‘swan neck’, into another receptacle, where it is cooled and becomes a liquid once again. Depending on the type of spirit required, a second or even a third distillation may be undertaken. It requires great skill to control the heat of the fire and, once the still starts to run, the process cannot be stopped, so that stillmen often sleep alongside their stills when distilling is taking place. Another decision depending largely on the experience and skill of the operator – even in these days when instruments provide much information and mechanical devices control what were previously rather haphazard operations – is the decision when to cut the ‘heads’ and ‘tails’ of the distillate.
These are respectively the liquid that first comes over into the cooling vessel; this may be much too harsh and contain too many impurities to form a harmonious element in the ultimate distillate: the final ‘tail’ may be weak and insipid. So the stillman directs the distillate to be ‘cut’ at a certain moment: that is, he directs the first and last parts of the distillate away from the heart or main portion, and these are usually redistilled subsequently. The pot still produces a distillate of individuality; two neighbouring stills of apparently identical design and size, making use of the sameand controlled in apparently the same way, will yield different distillates, as has been found in the production of malt whisky.
All straight malt Scotch, Irish whiskey and Cognac are made by pot stills, also some special rums. The pot still is also used for part of the spirit required in many blends of the world’s spirits. Originally evolved by the Arabs, for making perfumes, the use of the pot still seems to have been first known in Europe in the 13th century, being probably introduced by the Moors during their occupation of Spain. Pot stills are all made of copper. The word ‘alembic’ means a pot still.