53 



enquiries into this process, but his experience above referred to does 

 not lead him to anticipate much success from such a system.* 



In other cases, the air has been replaced with gases such as pure 

 nitrogen, carbon dioxide, and sulphur dioxide. No material postpone- 

 ment of change occurred in either of the experiments, though in that 

 with sulphur dioxide the hops came out of the cylinder in a curiously 

 green condition, but were not found to be superior in flavour or in 

 resin value to those stored under ordinary conditions. 



If, as the writer believes, the assumption is correct that the action 

 of ferments is mainly responsible for deterioration, then an explanation 

 is afforded of the undoubted success of cold storage. If we reverse 

 the process, and hops are stored at relatively high temperatures, the 

 effect of temperature is still more markedly shown. The writer some 

 years ago made experiments with pockets of consecutive numbers 

 of the same growth of hops, placing the pockets in stores, the tempera- 

 tures of which were respectively 55 (this being taken as a standard), 

 65, 75, and 83 F.t The deterioration which occurred may be stated 

 as follows : In three months the pocket stored at 83 had undergone 

 as much deterioration as that stored at 55 in a year. In five and 



* Since this article was published, the writer has had an opportunity of 

 personally examining the system of storage in vacuum rei erred to. Hops are 

 placed in iron cylinders (the size most convenient appearing to be one sufficient 

 to hold a pocket or bale) subjected to a high vacuum and stored in an ordinary 

 warehouse. Hops were examined which had been thus stored for some five 

 years. On opening, the result was somewhat disappointing, the hops having 

 acquired a peculiar rancid odour, having lost their rub, and were in a condition 

 such as no brewer could regard as superior to an old-old. This experience does 

 not however necessarily prove the failure of the system, for the cylinder had 

 been opened for the purpose of sampling and inspection several times in the 

 course of three or four years, and the hops almost certainly must have been 

 damaged by that cause. Certain samples of hops had been placed in glass tubes 

 which were vacuumized and sealed, and the examination of these would be far 

 more conclusive than of a sample which, although under vacuum, had been on 

 several occasions exposed to the air for short periods. Assuming, however, the 

 success of the vacuum system to be demonstrated, it remains to be seen whether 

 in practice it would be so economical as cold storage. The cost of the cylinders 

 is considerable, and their weight would be a very serious matter in a store 

 holding some hundred pockets of hops. On the other hand the actual cost of 

 working would be confined to vacuumizing in the first instance, and possibly 

 raising the vacuum had it fallen on storage. It is sufficient to say that the 

 vacuum system does not show any very apparent advantages over the proved 

 and thoroughly successful system of cold storage. 



f The temperature was not constant, and occasionally fluctuated between 80 

 and 90. Such variation would not, however, materially affect the actual 

 temperature of the hops themselves. 



