168 TROPICAL AGRICULTURE CHAP. 



coffee, which is a variety of the Arabian species with very 

 small beans, the chop must be approached very close to 

 the grater, and, in the case of the large berries of the Liberian 

 coffee, it must be set much further away. There is a hopper 

 at the top to receive the berries and to conduct them to the 

 grater, and below,, a sieve is so arranged, on an inclined 

 plane, that the crushed berries falling on to it are set in mo- 

 tion, the beans passing through the sieve and the pulp or 

 tails rolling away. 



FERMENTATION AND WASHING. As the beans come 

 from the pulper, they are covered with a sticky mucilaginous 

 material, which is removed by fermentation or by soaking in 



Cisterns. tubs or cisterns of water. When they are to be fermented, 

 they are put in barrels or tubs and allowed to remain for 

 twenty-four hours, or until the mucilage is easily separated ; 

 and then they are washed in water, and put out to dry in the 



Parchment sun in trays or on platforms. The coffee is then in the form 

 of " parchment," and it may be kept so for a very long time, 

 as it has its natural protective covering on it. 



HULLING OR PEELING. This consists in the removal of 



parchment and the thin under-coat called the silver-skin, 



which is done by various machines called hiillcrs, or by 



pounding the parchment coffee in large wooden mortars. 



Hulling When the hulling has to be done on a very large scale a 



machinery. c i rcu i ar trough, in which a large and heavy wooden or stone 



wheel is made to revolve, is employed. The parchment 



coffee is put in the trough and the wheel is made to pass 



over it. The parchment is crushed and broken into small 



pieces, but the coffee itself, if properly dried beforehand, is 



Hulling not uninjured. In all cases the parchment coffee must be well 



in wet warmed in the sun before it is peeled, and on no account 



weather. should the peeling operation be performed on a wet or damp 



day. A bushel of parchment coffee will usually give half 



the quantity of clean beans, but the proportions vary very 



