134 COCOA AND CHOCOLATE 



(h) Grinding the Cacao Nibs to Produce Mass. 



In this process, by the mere act of grinding, the 

 miracle is performed of converting the brittle frag- 

 ments of the cacao bean into a chocolate-coloured fluid. 

 Half of the cacao bean is fat, and the grinding breaks 

 up the cells and liberates the fat, which at blood heat 

 melts to an oil. Any of the various machines used in 

 the industries for grinding might be used, but a special 

 type of mill has been devised for the purpose. 



In the grinding room of a cocoa factory one becomes 

 almost hypnotised by a hundred of these circular mill- 

 stones that rotate incessantly day and night. In Messrs. 

 Fry's factory the " giddy motion of the whirling mill " 

 is very much increased by a number of magnificent 

 horizontal driving wheels, each some 20 feet in diam- 

 eter, which form, as it were, a revolving ceiling to the 

 room. Your fascinated gaze beholds " two or three vast 

 circles, that have their revolving satellites like moons, 

 each on its own axis, and each governed by master 

 wheels. Watch them for any length of time and you 

 might find yourself presently going round and round 

 with them until you whirled yourself out of existence, 

 like the gyrating maiden in the fairy tale." 



In this type of grinding machine one mill stone 

 rotates on a fixed stone. The cacao nib falls from a 

 hopper through a hole in the centre of the upper stone 

 and, owing to the manner in which grooves are cut in 

 the two surfaces in contact, is gradually dragged be- 

 tween the stones. The grooves are so cut in the two 

 stones that they point in opposite directions, and as 

 the one stone revolves on the other, a slicing or shear- 

 ing action is produced. The friction, due to the slicing 

 and shearing of the nib. keeps the stones hot, and they 

 become sufficiently warm to melt the fat in the ground 

 nib, so that there oozes from the outer edge of the 

 bottom or fixed stone a more or less viscous liquid or 

 paste. This finely ground nib is known as " mass." It 

 is simply liquified cacao bean, and solidifies on cooling 

 to a chocolate coloured block. 



