CHAPTER LXIV. 

 THE CHEMISTRY OF ALCOHOLIC FERMENTATION. 



By Dr. ARMINIUS BAU, 



Chemist to the Kaiserbrauerei, Bremen. 



322. The Chemistry and Chief Products of 

 Alcoholic Fermentation. 



As already remarked in the introduction to vol. i., it must have 

 been noticed, at a very early date, in connection with the produc- 

 tion of wine, mead, and other alcoholic beverages from must, diluted 

 honey, and similar raw materials, that the original sweet flavour 

 disappeared, a frothy head being formed and a gas disengaged ; 

 and that the effect of the fermented liquor on the human organism 

 was quite different from that of the fresh grape juice or sweet 

 solutions of other substances employed. In spite of this, how- 

 ever, the changes occurring during fermentation long remained in 

 obscurity ; and the first researches in this direction were devoted 

 to the origin of the alcohol, rather than to the remarkable forma- 

 tion of the frothy head or the liberation of the pungent-smelling 

 gas. When the Alexandrian school had improved the originally 

 primitive apparatus of distillation, experiments were made in dis- 

 tilling wine, and a product was obtained exhibiting the intoxicating 

 properties of that beverage in an intensified degree. The discovery 

 and preparation of alcohol resulted from the invention and elabo- 

 ration of methods of distillation. A description of these latter 

 can be found in the commentary on the works of Democritus 

 who was presumably one of the earliest alchemists of whom we 

 have any knowledge published by Synesios, who studied in 

 Alexandria at the beginning of the fifth century. It is known 

 that wine was distilled as long ago as the eighth century of our 

 era, spirit of wine having been referred to in the writings of the 

 alchemist Geber. It is also probable that early attempts were 

 made to concentrate and rectify the aqueous distillate from wine by 

 redistillation; and the Spaniard, Raymundus Lullus (1235-1315), 

 found that this result could be effected by treating the distillate 

 with caustic potash, followed by redistillation. About the year 

 1413, Basilius Valentinus wrote a clearer description of the 

 method for obtaining a more highly concentrated product ; but 



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