STILLS: SHAPES ALSO MATTER (PART I)
Continuous or discontinuous distillation? Direct fire, bain-marie or steam still? And the distillation: single, double or triple? Not all stills are the same and each instrument has peculiarities that characterize the final result of the distillation.
Over the centuries, increasingly sophisticated instruments have been developed with different operating criteria; presenting some of them will allow us to define the characteristics that distinguish the distillates depending on the distillation system used.
Thus, wanting to reconstruct the identikit of a distillate, we can make a first distinction between continuous and discontinuous distillation systems. The continuous distillation system, developed by Aeneas Coffey (hence the name Coffey Still), is not considered an artisanal system. This usually involves columns with rectification plates that make the distillate more neutral, bringing it to a high alcohol content in a single distillation. A characteristic of the continuous still is the ease of progressive loading of the raw material without the need to block the production plant. This type of plant is used, as well as for the production of industrial alcohol, also to produce distillates where the degree of purity represents a determining factor in defining the quality, an example above all being Vodka.
The discontinuous system (the raw material must be loaded with the still still) usually involves a double distillation with the cutting of the heads and tails carried out in the second distillation. This production technique guarantees the purity and healthiness of the distillate without losing all the characteristics of the raw material. Discontinuous stills or Pot Stills (due to the similarity of the boilers to the shape of a pot) are commonly considered artisanal stills and can be divided into direct fire, bain-marie and steam stills.
The direct fire still characterizes the distillate more markedly due to the high temperatures that can be reached with direct contact of the flame on the boiler. It is historically the peasants' still and the most difficult to control. With this type of still, some master distillers opt for a single distillation with clearer cuts of the head and tail fractions in order to preserve a certain rusticity of the distillate. The bain-marie processing allows for the best temperature control, guaranteeing a softer distillate on the palate. There is also an increase in distillation times compared to steam stills, traditionally used for pomace, where the steam reaches temperatures above 100°C.
Beyond the distinctions made, each still has its own shape and proportions which have adapted over time based on the quantities and types of raw materials to be distilled. So even today the construction characteristics of a still are a secret kept by a few craftsmen.