58 QUALITY AND KEEPING OF HOPS. STATISTICS OF 



account of the loss of the volatile oil. The bitter substance 

 which exists in hops does not appear to decrease, the tannic 

 acid gradually diminishes in quantity ; and the volatile prin- 

 ciple escapes from the plant and spreads in the atmosphere, 

 or partly oxidizes, which gives the hops a disagreeable odour. 



Moreover, hops, like the leafy parts of plants, or the parts 

 of the leaves "which are not very thick, when they are exposed 

 to contact with the air, are subject to a species of decom- 

 position which on the Continent has received the name of 

 verwesung. The plant assumes a dark colour, and all its 

 constituent parts are brought more and more into the do- 

 minion of chemical transformation. It has been proposed 

 to dry the hops and then to keep them from contact with the 

 air, which would do away with, or at least lessen, two of the 

 conditions which tend to produce a chemical transformation. 



Liebig pronounced in favour of sulphuring hops, and he 

 rightly maintained the innocuity of this simple means of 

 preserving a portion of the plant, which, without it, would 

 rapidly enter into decomposition, and which by these means 

 may be transported and preserved, without declining in value 

 or acquiring any injurious property. He cited in support of 

 his opinion the proposition of Braconnot, to preserve, by 

 means of sulphurous acid, the vegetables employed for domestic 

 use, such as chicory, asparagus, sorrel, &c. 



Sulphuring. To preserve the hops they are usually sul- 

 phured, that is, subjected to the action of vapours of burning 

 sulphur, 1 Ib. to 2 Ibs. of sulphur being employed to 1 cwt. 

 of hops. Old hops are sometimes treated in this manner to 

 impart the colour and appearance of freshly dried hops ; but 

 the fraud can be detected by the odour. The best method of 

 testing for sulphur in hops is as follows : A sample of the 



