A distillery’s style is determined by the shape and size of its 100-litre single malt whisky stills. These stills often serve as the embodiment of a distillery’s unique character. Just as no two leaves are exactly alike, so too are the stills and processes of each distillery distinct.
There are two main types of 100-litre single malt whisky stills.
Pot stills and column stills
So, what are their operating principles and characteristics? And which raw materials are they primarily suited to?
Pot stills
Key features: Batch distillation, primarily used for malt whisky; pot stills are the oldest and simplest distillation apparatus, typically made of copper.
Principle of operation: Upon heating, the alcohol evaporates first; the vapour passes through the neck of the still into the condenser, where it cools to form the spirit.
Production capacity: Multiple distillations are usually required to obtain a new make spirit with a higher alcohol content; overall, distillation efficiency is relatively low.
Flavour characteristics: Retains a variety of flavours from the fermentation process. It is rich in flavour compounds, yields a low alcohol output, and produces a spirit with a full-bodied texture.
Column still
Main characteristics: Also known as a ‘Coffey still’. Primarily used for the continuous distillation of grain whisky.
Principle of operation: Alcohol-laden vapour is progressively purified through a series of trays, gradually increasing the alcohol concentration in the vapour until the concentration required by the distillery is achieved.
Production capacity: There is no need for batch distillation or the collection of the ‘heart’ of the distillate. High-proof alcohol can be produced consistently 24 hours a day, all year round, with very high efficiency.
Flavour Profile: Removes most flavour compounds from the spirit. The alcohol is pure, with high yield and a light body.
Based on different heating methods
These can be broadly categorised into direct heating and indirect heating. Different processes create distinct flavour profiles, and both heating methods have their respective advantages.
