AN IMPROVED PROCESS FOR THE EXTRACTION OF FAT FROM CACAO AND IMPROVED MACHINERY OR APPARATUS IN CONNECTION THEREWITH
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by Friedrich Carl Glaser at the Office
of the Commissioners of Patents on the 27th September 1883. A communica-
tion from Dr. Hugo Michaelis, a person resident at Berlin, Prussia, Germany.
FRIEDRICH CARL GLASER, of Berlin, in the Kingdom of Prussia and Empire of
Germany, Engineer and Patent Solicitor. "AN IMPROVED PROCESS FOR THE
EXTRACTION OF FAT FROM CACAO AND IMPROVED MACHINERY OR APPARATUS IN
CONNECTION THEREWITH a communication from Dr. Hugo Michaelis, a person
resident at Berlin, Prussia, Germany,
"
All the methods hitherto in use for the extraction of fat from Cacao give very
deficient results. Of the 50 per cent of fat which Cacao on the average contains
only about 20 per cent can be removed and the so called "oil free" Cacao of
commerce always contains at least 25 per cent.
Therefore whilst on the one hand a product so valuable as Cacao butter remains
in part unconsidered in the manufacture of Cacao-powder, on the other hand such
an excellent means of sustenance and enjoyment as is Cacao is injuriously affected
owing to its indigestibility by reason of the large quantity of fat contained in it.
The customary method of extracting fat is as follows:-
The roasted and shelled Cacao beans are crushed between rolls and the resulting
substance is subjected to great pressure in presses. Lately hydraulic presses have
been employed. At a pressure of about 300 atmospheres about 50 per cent of the
whole contents of fat is obtained which still leaves about 25 per cent contents of
fat. A perfect extraction of fat could not even be attained by a considerable
increase of pressure, as the substance, like a sponge, always retains a portion of
the fat.
Trials of methods for determining the contents of fat have been carried out in the
laboratory, by which it was hoped to effect a perfect removal of the fat by a process
of chemical extraction by means of Ether or other known analogous Agents acting
as solvents of fat, but they also failed.
The cause of this was that in the course of treating by the extraction process
larger quantities than those which are considered in laboratory experiments, a mass
was formed that was perfectly impenetrable to the medium of extraction.
In the following description processes will be explained by which complete
removal of the fat from Cacao is effected by the prevention of the last mentioned.
drawback, and by which a chemical process of Cacao extraction is so carried out,

page_text: that, either by the admixture of certain substances, or by the arrangement of a
stirring apparatus, a continuous light spongy state obtains during the process of
extraction.
In the first process, the Cacao substance obtained by crushing the roasted and
shelled Cacao beans is mixed with any suitable comminuted substance which is not
affected by Ether. This mixture is subjected to the process of extraction in suitable
extraction vessels in the ordinary way. As the Cacao substance is kept porous by
the mixture it cannot cake together and thus presents a large surface to the medium
of extraction, Chopped Straw, comminuted mineral substances, etc, are suitable for
forming the admixture. The substance found preferable for this purpose is
comminuted Cacao husks. After the extraction has been effected this material
may easily be separated from the Cacao-powder from which the fat has been
removed, by means of sieves, to again serve afresh as a suitable mixing material, in
the process of fat extraction.
In the second process the continuous porosity of the Cacao substance is main-
tained by a stirring apparatus in which the process of extraction is performed by
means of media of extraction being solvents of fat, with a simultaneous stirring of
the substance, and then by allowing the stirred up substance to settle, the medium
of extraction containing the extracted fat collects on the surface and may be removed
by skimming or drawing off.
The special process to be applied in this case may be carried out by means of the
apparatus herein after described, which may however be suitably altered in its
arrangement to correspond with the purpose in view.
Two boilers are arranged one above another and connected by a bent syphon
shaped tube which at the end projecting into the upper boiler is provided with a
filter bag.
Further, for the upper boiler a stirring apparatus is provided the axis of which
turns in a hydraulic closure at the top of this upper boiler.
Between the two boilers the syphon pipe is provided with a cock; the boilers
are constructed with jackets and may be heated by steam circulating in the space
between the jacket and the boiler. By means of a second tube projecting into the
lower boiler and divided at the bottom of the same where it is finally perforated,
air or other suitable gas may be forced at the ordinary or at an increased temperature
into the boiler, or air may be drawn out of this lower boiler.
In working, the upper boiler is say about half filled with the substance to be
deprived of fat. The lower boiler is supplied with Ether. By heating the lower
boiler the Ether is formed into vapour, passes through a tube in connection with a
cooling worm, is there distilled, and then flows through a larger tube on to the
Cacao substance in the upper boiler. At the same time the stirring apparatus is
put in motion and this upper boiler is heated by steam conducted thereto for the
purpose,
When the Ether in the lower boiler is distilled off, the stirring mechanism is
stopped and the substance allowed to rest for a short time (about 10 minutes).
During this time the Cacao substance falls to the bottom, whilst the clear Ether
solution, charged with a portion of the fat, separates and goes to the top.
When this has taken place some air is drawn out of the lower boiler through the
tube which at the bottom is divided into two branches, but of course after the cocks
of all the other tubes leading to the lower boiler have been shut. The cock of the
syphon pipe being then opened, this pipe becomes at once filled and the Ether
solution flows out of the upper boiler into the lower one.
Thereupon the distillation of the Ether from the lower boiler is commenced
afresh and the stirring mechanism again set in motion, and so on. When this
operation has been repeated 4 or 5 times the substance is thoroughly deprived of
fat. The whole of the fat will then be found in solution in the Ether in the
lower boiler. The Ether is distilled off and received through a cock on the
cooler which is opened whilst the tube leading from the cooler to the upper boiler
is shut off.

page_text: The rest of the Ether remaining behind in the fat is driven out by air which
flows in through the tube in the lower boiler which at the bottom of the said boiler
is divided into two branches. The air (whilst at the same time the lower boiler is
being heated) passes through the fat and goes by way of the syphon pipe through
the Cacao substance, which during the operation is again moved by the stirring
mechanism, and then through a larger tube reaches the cooler in which the Ether
is condensed.
By this operation the Cacao substance is simultaneously freed from the retained
Ether and further again impregnated with the aroma which the fat had absorbed.
At the end of the tube of the upper boiler connecting with the cooler is arranged
filtering material or any other means for preventing the Cacao powder being drawn
into the tube by the air current.
The fat is finally drawn off through a cock at the bottom of the lower boiler.