Scotch Series 20: Distillation

One of the reasons behind the ruling that the level of ethanol in new make spirit for Scotch cannot legally exceed 94.8% is so features from the fermentation & raw materials are retained. In gin production, the ethanol is purified by repeat distillation to reach at least 96% abv, producing a neutral spirit. In America pharmaceutical companies are the dominant suppliers of gin spirit, as they have huge stills designed to produce extremely pure ethanol for drug manufacture.  The initial alcohol concentration coming off a wash still (dependant on the alcohol content of the wash) is around 45% abv. Distillation continues to allow the concentration to drop to 1%, giving a low wine fraction around 23% abv. Spent lees is the name given to what is left in the still. Lees are the dead yeast cells left over from fermentation.