140 



Cultivation of the Hop Crop. 



[May, 



portant to realise that the quantities contained in the bushel 

 measure are very different in each case, that measured from 

 the bin being much less than that measured in the basket, and 

 hence prices paid for picking as well as other data based upon 

 these units of measure, are not comparable. 



Drying. — Until nearly the end of the twentieth century hop 

 drying was practised much more as an art than a science ; the 

 hop dryer was all-powerful and carried out his work by rule of 

 thumb; he was guided only by the experience of his former 

 chief dryer, under whom he had worked as assistant, and 

 generally paid scant attention to the suggestions of his employer, 

 who probably knew little about the principles underlying the 

 practice of hop-drying. 



In the last decade of the twentieth century Sir A. D. Hall, 

 then Principal of Wye College, began to investigate the sub- 

 ject; he showed how best to make use of the thermometer by 

 placing it just below the hops so that the temperature of the 

 air as it entered the hops could be gauged. He also published 

 a leaflet* showing how the temperature of the air should be 

 regulated during the period of drying so that the hops could be 

 economically dried without being spoilt in the process. As a 

 result of this work every grower can now exercise direct control 

 over his hop-drying by installing a thermometer bulb just below 

 the drying hops, connected with a scale outside the oast upon 

 which the temperature of the drying air can be read. With 

 such thermometers the grower can direct his dryer to follow the 

 table of temperatures suggested by Hall, and progressive hop- 

 growers have adopted or are adopting this or some similar 

 method of control. There is still, however, much to be learnt 

 about the principles of hop-drying, and the hop-growing industry 

 is looking forward in the course of the next 10 years or so to 

 the accumulation of much valuable knowledge by those in con- 

 trol of the experimental hop-drying plant recently installed 

 under the Brewers' Institute Eesearch Scheme on a farm belong- 

 ing to Messrs. Whitbread & Co., near Paddock Wood. 



The Principles of Hop-drying. — Pipe hops when picked for 

 drying normally contain 60 to 75 per cent, of moisture, unripe 

 hops in moist weather may contain 80 per cent, of moisture, 

 and very ripe hops in dry weather may contain as little as 

 50 per cent. During the drying process the moisture content 

 is reduced to about 5 to 8 per cent., but is allowed to rise again 



* Leaflet No. 5. South Eastern Agricultural College, Wye. "The Temper- 

 atures of Hop Drying." 



