AND CHEMISTKY 



essential oil are added per hectolitre (22 gallons;; tEe extrac- 

 tion of the bitter principle and of the tannin, the clarification 

 and the fermentation are effected perfectly, the beer is of 

 superior quality, very thin, limpid, clear, and creamy, being 

 characterized by a delicious bouquet of hops, and keeps much 

 better as, under Hie influence of the essential oil, the myco- 

 demae, microscopic animalculae, -which, by their presence in 

 beer, cause an acetic and putrid fermentation, perish. 



Chemistry of Hops. Messrs. Pay en and Chevallier, so 

 far back as 1830, and even before, determined that the 

 yellow secretion of hops, a bitter and aromatic element, was 

 the sole source of the flavour, the strong odour, and, in 

 fact, the active principle; and that the bracts of the cones 

 which were not touched with the yellow substance, had no 

 more aromatic odour or flavour than dry hay. They also 

 ascertained that this yellow powder or secretion is found 

 in varying proportions in different kinds of hops, and hence 

 their real and useful value differs materially. 



The following is the mode in which these able chemists 

 made the analysis, which is more mechanical than chemical. 

 " The strobiles, or cones, of the hops are taken when well 

 dry, and the foreign matters which they contain are separated 

 as much as possible ; they are then placed on a fine horsehair 

 sieve, pressed with the hand, and the sieve shaken; the 

 pulverulent secretion passes through the meshes of the sieve, 

 leaving the bracts on the top. These are again submitted to 

 pressure and agitation, to separate any more of the yellow 

 powder which may have escaped, until nothing is left but the 

 waste bracts. Care, however, must be taken not to crush or 

 bruise these, so that none may pass through the meshes to 



