That the "Indian" practice of removing the shells was followed from the commencement of the industry in England, is shown by the old plate which we have reproduced on [p. 120] from Arts and Sciences.
The removal of the shell, which in the raw condition is tough and adheres to the kernel, is greatly facilitated by roasting. If we place a roasted bean in the palm of the hand and press it with the thumb, the whole cracks up into crisp pieces. It is now quite easy to blow away the thin pieces of shell because they offer a greater surface to the air and are lighter than the compact little lumps or "nibs" which are left behind. This illustrates the principle of all shelling or husking machines.
(e) Breaking the Bean into Fragments.
The problem is to break down the bean to just the right size. The pieces must be sufficiently small to allow the nib and shell readily to part company, but it is important to remember that the smaller the pieces of shell and nib, the less efficient will the winnowing be, and it is usual to break the beans whilst they are still warm to avoid producing particles of extreme fineness. The breaking down may be accomplished by passing the beans through a pair of rollers at such a distance apart that the bean is cracked without being crushed. Or it may be effected in other ways, e.g., by the use of an adjustable serrated cone revolving in a serrated conical case. In the diagram they are called kibbling cones.
SECTION THROUGH KIBBLING CONES AND GERM SCREENS.
(f) Separating the Germs.
About one per cent. of the cacao bean fragments consists of "germs." The "germ" is the radicle of the cacao seed, or that part of the cacao seed which on germination forms the root. The germs are small and rod-shaped, and being very hard are generally assumed to be less digestible than the nib. They are separated by being passed through revolving gauze drums, the holes in which are the same size and shape as the germs, so that the germs pass through whilst the nib is retained. If a freakish carpenter were to try separating shop-floor sweepings, consisting of a jumble of chunks of wood (nib), shavings (shell) and nails (germ) by sieving through a grid-iron, he would find that not only the nails passed through but also some sawdust and fine shavings. So in the above machine the finer nib and shell pass through with the germ. This germ mixture, known as "smalls" is dealt with in a special machine, whilst the larger nib and shell are conveyed to the chief winnowing machine. In this machine the mixture is first sorted according to size and then the nib and shell separated from one another. The mixture is passed down long revolving cylindrical sieves and encounters a larger and larger mesh as it proceeds, and thus becomes sieved into various sizes. The separation of the shell from the nib is now effected by a powerful current of air, the large nib falling against the current, whilst the shell is carried with it and drops into another compartment. It is amusing to stand and watch the continuous stream of nibs rushing down, like hail in a storm, into the screw conveyor.