The thick fluid of the consistency of treacle flowing from the grinding-mills is poured into round metal pots, the top and bottom of which are lined with pads of felt, and these are, when filled, put under a powerful hydraulic press, which extracts a large percentage of the natural oil or butter.  The pressure is at first light, but as soon as the oil begins to flow the remaining mass in the press-pot is stiffened into the nature of indiarubber, and upon this it is safe to place any pressure that is desired.  As it is not advisable to extract all the butter possible, the pressure is regulated to give the required result.  In the end a firm, dry cake is taken from the press, and when cool is ground again to the consistency of flour; this is the “cocoa essence” for which the firm of Cadbury is so well known in all parts of the world.[13]

Between cocoa and chocolate there are essential differences.  Both are made from the cocoa nib, but whereas in cocoa the nibs are ground separately, and the butter extracted, in chocolate sugar and flavourings are added to the nib, and all are ground together into a paste, the sugar absorbing all the superfluous butter.  If good quality cocoa is used, the butter contained in the nib is all that is needful to incorporate sugar and nib into one soft chocolate paste for grinding and moulding, but in the commoner chocolates extra cocoa butter has to be added.  It is a regrettable fact that some unprincipled makers are tempted to use cheaper vegetable fats as substitutes for the natural butter, but none of these are really palatable or satisfactory in use, and none of the leading British firms are guilty of using such adulterants, or of the still more objectionable practice of grinding cocoa-shells and mixing them with their common chocolates.[14]

Flavouring is introduced according to the object in view; vanilla is largely employed in this country, though in France and Spain cinnamon is used, and elsewhere various spices.  Willoughby, in his “Travels in Spain” (1664), writes: 

“To every three and a half pounds of powder they add two pounds of sugar, twelve Vanillos, a little Guiny pepper (which is used by the Spaniards only), and a little Achiote[15] to give a colour.  They melt the sugar, and then mingle all together, and work it up either in rolls or leaves.”

Another writer says:  “The usual proportion at Madrid to a hundred kernels of cocoa is to add two grains of Chile pepper, a handful of anise, as many flowers—­called by the natives vinacaxtlides, or little ears—­six white roses in powder, a pod of campeche,[16] two drachms of cinnamon, a dozen almonds and as many hazel-nuts, with achiote enough to give it a reddish tincture; the sugar and vanilla are mixed at discretion, as also the musk and ambergris.  They frequently work this paste with orange water, which they think gives it a greater consistence and firmness.”

[Illustration—­Black and White Plate:  Bournville Village:  Laburnum Road.]