ii4 The Fermentation of Cacao 



time required for completing the process was 

 stated to be two days. 1 



Consul Spengler, now in Lisbon, but 

 formerly manager of the Monte coffee planta- 

 tion in San Thome, introduced a modern type 

 of tunnel-drying some years ago. Indepen- 

 dently, and without knowing of this method, 

 I also worked out a scheme of tunnel-drying, 

 which differs from that of Spengler in that 

 a ventilator is attached to one end of the 

 tunnel, and the construction is as follows : Two 

 tunnels, divided by a middle wall, are 20 m. 

 (65 ft. 6 in.) long, 1*5 m. (4 ft. 11 in.) wide, 

 and 175 m. (5 ft. 9 in.) high. A 2O-cm. or 

 8-in. gauge rail runs down the centre of each 

 tunnel, the latter being closed at the ends by 

 double doors. In a convenient position at one 

 end of the tunnels is a heating apparatus from 

 which the hot air is driven through the venti- 

 lators into the separate tunnels. In order to 

 increase the draught, a flue communicates with 

 the other end of each tunnel, just as in Spengler's 

 method, and this draws off the hot air. Trays 

 filled with cacao are placed on small trolleys 

 and these are run into the tunnels, and as soon 

 as the cacao on the front trolleys are suffi- 

 ciently dried, these are run out at the other 

 end, where the hot air enters, and the trolleys 

 on which the cacao is not yet sufficiently dry 



1 This is on the principle of the American fruit dryers, 

 and cannot prove a success unless a fan, or other means 

 for providing a forced draught, is supplied. H. H. S. 



