502 THE DISTILLING INDUSTRY IN IRELAND. 



The degree to which fermentation is carried is very different in distilling 

 from that which prevails in brewing. The brewer desires to retain as fax as 

 possible the aroma of the hops and malt and to convert only a portion of the 

 sugar into alcohol, thus leaving a large proportion of the sugar and dextrine 

 in the beer ; the distiller on the other hand desires to convert as much as 

 possible of the sugar into alcohol and at the same time to avoid the forma- 

 tion of secondary products, more especially the oxidation of the alcohol 

 into acetic acid. 



The second stage in the process now begins. The fermented wort, 

 known as " wash," is a fluid containing varying pro- 

 Distillation portions of alcohol, unfermentable grain extract and 

 water, and the object of the distiller is to isolate the 

 spirit as effectually as possible. This is done by 

 distillation, i.e., by converting the volatile constituents of the wash into 

 vapour. Distillation is a generic name for a class of operations, all of which 

 agree in one point, namely, that the liquid operated upon is heated in a 

 closed vessel or still, and thereby wholly or partially convertec into vapour 

 which is then condensed by cold into the liquid state. The distillation of 

 spirits is, thus, the process of separating alcoholic spirits from fermented 

 hquors. Water boils at 212° F., and alcohol at 173°, and a mixture of equal 

 parts of alcohol and water will boil at the intermediate temperature of about 

 192^; hence the boiling point of "wash" depends on the proportion of 

 spirit which it contains. The more volatile spirituous vapour first passes 

 over to be condensed at a low temperature which has to be increased as the 

 spirit becomes weaker by admixture with water. The apparatus is always 

 arranged in such a way that the vapour is cooled to condense 'nto the liquid 

 form again, wliich runs into separate vessels called " Receivers." In 

 whiskey distilleries nearly the whole of the alcohol is separated from the 

 water by repeated fractional distillations, the distillates being collected in 

 several vessels as " Low Wines," " Feints," and " Whiskey." 



All classes of distilling apparatus may be classified under three heads, 

 viz. : — first, stills heated and worked by the direct application of a fire, 

 secondly, stills worked by the action of steam blown direct into the alcohohc 

 solution from a steam boiler ; and thirdly, stills heated by steam passing m 

 pipes through the alcoholic solutions to be acted upon. But the apparatus 

 used for the distillation of spirits are commonly divided into two classes : — 

 pot-stills and patent stills. 



To the first of these classes, viz., stills heated by the direct application of 



fire, belong to the earliest and simplest forms of dis- 



The Pot Still tillatory apparatus including the famous "Pot-Still" so 



generally used in Ireland. This still is an almost 



flat-bottomed copper pot, with a high head to prevent 



the fluid within from boiling over. From the top of the head runs the 



" worm," i.e., a tube connected with the head and carried in a spiral form 



round the inside of a vessel or tub filled with cold water, which acts as a 



condenser. The alcohol leaves the still in the form of vapour which is 



condensed into a liquid and cooled in its passage through the " worm " to 



the Receiver. The spirit thus collected has to be re-distilled until 



it becomes much stronger and cleaner. The first distillate from the 



still is termed " Low Wines," and passes into the " Low Wine Receiver," 



whence it is transferred to the first " Low Wine Still " to be again 



