The Distillation of Whisky

Abstract

The chemistry of whisky, regarded from the point of view of the finished article; is a subject to which some attention has been directed of late years, but so far the chemistry of the technology of whisky making, t.c, the chemistry of the distillation processes, has scarcely been touched upon.It is with this part of the subject that the experimental data recorded in this paper deal. At the same time it is necessary to state that the figures given are only to be regarded as the first steps in an attempt to cast some light on a difficult and intricate subject. In order that the figures may be comprehensible to those not familiar with the methods of distillation of potable spirits as carried out in the United Kingdom, we think it desirable to preface the experimental part of the paper with a brief account of the manufacturing operations as far as they touch upon the technology of the distillation process as such. The method of distillation, that is, the type of still employed, and the manner of working it, is so closely associated with the history of the whisky industry, that a few words with regard to the latter may not be out of place. Substantially, a spirit of the whisky type, that is to say, a potable liquor distilled from cereal grains, has been known for a very long time. There is much evidence to show that a spirit of this kind was made in the East before the advent of the Christian era. " Usquebaugh," from which the relatively modern word " whisky " is derived, was known in Ireland in the 12th century, but it was not until the reign of Henry VIII that the manufacture of a potable THE DISTILLATION OF WHISKY. 497 spirit made from grain was commenced in England. The origin of whisky making in Scotland is not clear. Scotch spirit seems to have been well known in England in the 17th century, but it is difficultto form an opinion as to the nature of the product then manufactured,, or the materials used. It appears fairly certain, however, that the? word "Usquebaugh" originally denoted not a simple spirit such as the modern whisky, but that it was a cordial made from grain or molasses spirit mixed with saffron, sugar, nutmegs, and various other spices. The still originally employed was of a very simple pattern, resembling a kettle or simple retort. From this wore gradually evolved the modern " pot" and " patentM stills.The Pot Still.-The original object of distillation, as applied to potable spirits, was undoubtedly that of separating the volatile constituents of the wash (i.e., fermented wort) from the non-volatile constituents. As the technology of distillation progressed, it became apparent that by repeating the distillation process, by modifying the form of the still, or by collecting the distillate not as a whole but in several fractions, or by combining all or some of these modifications of the primitive process, the more valuable part of the volatile constituents, namely, the ethylic alcohol, could be obtained in a more concentrated form; and that, in addition to this, the quality of the distillate, viewed ...

Tackling Foam-Based Process Disruptions in Spirit Distillation by Thermal Energy Input Adaptations

“…With respect to distillation processes, the presence of excessive foams leads to the carryover of foams onto separation trays, product contamination, and increased cleaning demands. The effects are associated with reduced separation efficiency and process disruptions (Kister, 2003;Miller, 2019;Schidrowitz & Kaye, 1906). When it comes to column malfunctions in the distillation industry, foaming plays a major role (Kister, 2014).…”

“…Such adaptations already have a long history. For example, the elongated swan necks in Scottish pot stills in whisky distilleries were originally invented to prevent the transfer of rising foams into the product stream (Schidrowitz & Kaye, 1906). Unfortunately, larger distillation devices have a higher surface area, which is associated with higher process costs due to additional surface area heat radiation.…”