Cocoa and Chocolate
(i) Pressing out the excess of Butter.
A CACAO PRESS.
Reproduced by permission
of Messrs. Lake, Orr
& Co., Ltd.
The liquified cacao bean or "mass," simply mixed with sugar and cooled until it becomes a hard cake, has been used by the British Navy for a hundred years or more for the preparation of Jack's cup of cocoa. It produces a fine rich drink much appreciated by our hardy seamen, but it is somewhat too fatty to mix evenly with water, and too rich to be suitable for those with delicate digestions. Hence for the ordinary cocoa of commerce it is usual to remove a portion of this fat.
If "mass" be put into a cloth and pressed, a golden oil (melted cacao butter) oozes through the cloth. In practice this extraction of the butter is done in various types of presses. In one of the most frequently used types, the mass is poured into circular steel pots, the top and bottom of which are loose perforated plates lined with felt pads. A number of such pots are placed one above another, and then rammed together by a powerful hydraulic ram. They look like the parts of a slowly collapsing telescope. The "mass" is only gently pressed at first, but as the butter flows away and the material in the pot becomes stiffer, it is subjected to a gradually increasing pressure. The ram, being under pressure supplied by pumps, pushes up with enormous force. The steel pots have to be sufficiently strong to bear a great strain, as the ram often exerts a pressure of 6,000 pounds per square inch. When the required amount of butter has been pressed out, the pot is found to contain not a paste, but a hard dry cake of compressed cocoa. The liquified cacao bean put into the pots contains 54 to 55 per cent. of butter, whilst the cocoa press-cake taken out usually contains only 25 to 30 per cent. The expressed butter flows away and is filtered and solidified (see page 158). All that it is necessary to do to obtain cocoa from the press cake is to powder it.
SECTION THROUGH CACAO PRESS-POT AND RAM-PLATE.