52 



The proportion of water present in hops undoubtedly exerts a 

 considerable influence upon their keep. In a number of experiments 

 made some years back, the results of which were published at the 

 time, samples from the same kiln of hops were stored under similar 

 conditions, containing differing quantities of moisture. It was found 

 the lower the proportion of moisture the slower was the deterioration 

 of the hops. The reduction of moisture percentage may therefore be 

 fairly regarded as an important factor in determining the keeping power 

 of a hop ; and this, rather than " curing " in the same sense as that 

 word is applied to malt, is the object of the drying of hops on kiln. 

 All we are able to do in this direction is to reduce the moisture to a 

 fairly low proportion, to pack the hops without delay, and as tightly 

 as possible. 



But though the moisture is reduced to the limit of, say, 8 or 9 per 

 cent, we know from experience that hops stored at ordinary 

 temperatures undergo continuous alteration. The cause of this 

 alteration is not as yet fully worked out, but there is reason to believe 

 that the action both of zymes and enzymes is largely responsible for 

 the changes which take place. These changes were at one time 

 attributed to oxidation by exposure to air ; but experiments made with 

 hops stored in exhausted chambers showed that no postponement in 

 deterioration thereby resulted. It is, of course, impossible to secure a 

 perfect vacuum, and the hops were merely stored relatively out of con- 

 tact with the air, but inasmuch as the amount could only have been 

 something less than J-^-Q of that originally present, it is reasonable to 

 assume that had air been the factor determining the deterioration, 

 some marked difference would have been shown between the quality 

 of hops stored in vacuo and those stored in the ordinary manner, and 

 this was not the case. 



Some experiments* have been recently described in one of the 

 Trade journals, showing the effect of storage in a relatively perfect 

 vacuum, and hops subjected to these conditions have been stated to 

 retain their resin value, their aroma and colour to a remarkable 

 extent. The writer has had no opportunity of making personal 



* " Hops and their Storage," Brewers' Journal, pp. 6, 7, 8. 1901. 



