Kneader”, system Werner-Pfleiderer, is distinguished, as its name
implies, by a vacuum arrangement. As seen on illustrations 91 a
and b, this comprises a pyramid-like cover made of cast iron, and
shutting down air-tight, which is provided with indiarubber caulking,
and binding screws, and is fitted up for steam heating. It moves on
the frame of the machine and is counterpoised with weights, so as to
facilitate its raising and lowering. On the front part of the lid
there is a small aperture paned in with glass, and opposite on the
interior in a specially protected compartment occurs an electric light
arrangement, which admits of the continual observation of the material
during the working up processes. In addition, small quantities of cacao
mass can be introduced on removal of the glass pane without lifting
up the lid; so that the advantages of the aperture are twofold. The
upper part of the cover tapers off into a suction pipe, which itself
terminates in a flanged support intended as a finish to the conduit
from the airpump.
[Illustration: Fig. 91 b.]
The kneading trough of the machine is made of cast iron, provided with
a false bottom, and fitted up for heating with hot water or steam to a
pressure of 7 atmospheres, or for cooling down with cold water. By way
of rapid discharging, the trough is counterpoised with weights, and
can easily be tilted over by means of a hand winch. Its interior, as
also the kneading shovels, are clean scoured, and the bearings of the
shovels stopped with easily adjustable stuffing boxes. These stuffing
boxes (German Patent) are so fitted in that no greasing substances
whatever can penetrate to the cacao mass, which is of the highest
importance, as in the case of the ordinary stuffing boxes grease is
sucked up into the kneading trough by the action of the air pumps and
the material contained in this so rendered impure. The steam and water
conduit to and fro is effected by means of supple metallic hose, which
follow the movement of the trough as it is tilted.
The vacuum kneading machines have acquired great importance in the
manufacture of milk chocolates, where it is chiefly a question of
reducing mixtures of cacao, sugar, and condensed milk to a requisite
thickness. Lately the value of the machine has been regarded as
consisting in the main of the possibility of preparing cacao under
vacuum which it affords.
It is easy to understand that the treatment of the cacao under vacuum
demands a much lower temperature and takes place in about half the time
requisite for open machines, where it must be carried out against the
constant and contrary influence of the atmosphere, apart from the fact
that the vacuum kneader preserves the aroma far better.
The alkali solution used in disintegration may be prepared in vats
fitted with draw-off cocks, or, in small factories, in glass carboys
such as are used for the conveyance of acids. Of the fixed alkalis,
potash is preferable, since it is a natural constituent of terrestrial
plants and therefore of the cacao bean, and so its employment
introduces no foreign ingredient. Magnesium carbonate seems to find
favour in many quarters, but we consider it less suitable as being
insoluble in water, and therefore can only be incorporated with the
cacao mass in a state of suspension. It is sufficient to have a potash
solution some 90 or 95 % strong, answering to the requirements of
modern medical treatises.[130] The salt is soluble in an equal quantity
of water.
In preparing the solution, the best plan is to dissolve a known
quantity in from 3 to 4 times as much water at the temperature of the
room and then by diluting with water reduce this composition to the
required strength. As for each 100 kilos of cacao still undefatted from
2 to at the most 3 kilos of potash and from 15 to 20 kilos of water are
required, this 2 or 3 kilos of the salt should be dissolved in about 10
litres of water and the solution after diluted with the remainder of
the water.
In using volatile alkalis, which are nevertheless falling into disuse
more and apparently no longer maintain their reputation, ordinary
ammonium carbonate which may be easily obtained in powder form at any
chemist’s, or a solution of ammonia, such as spirits of sal-ammoniac,
may be used. The former is easily soluble in about five parts of water.
From ½ to 3 kilograms of ammonium carbonate are generally reckoned
for every 100 kilos of undefatted cacao material, and this amount is
dissolved in water, the whole of the salt being at once introduced into
from 15 to 30 litres, as when smaller quantities are used there ensues
a decomposition of the salt and one of the products of decomposition,
the carbonate of ammonium, remains undissolved.
The spirits of sal-ammoniac operate much more effectively than the
ammonium carbonate on account of their high percentage of ammonia,
and so only a third as much of this substance may be employed, and
generally even smaller quantities prove quite sufficient. Consequently
100 kilos of defatted cacao should be mixed with 0·5-1 kilo of ammonia
solution (specific gravity 0·96), previously diluted with 20 or at
the most 29 litres of water. The mixture should be prepared in glass
carboys immediately before use, because of the volatility of ammonia.
In the treatment of the cacao, salt solution and cacao are together
introduced into a melangeur, or better into the kneading and mixing
machine, and the apparatus being set in working order, steam enters,
and removes the quantities of water which have been added, as well as
the volatile alkalis. Whether all the water has been driven off or no
can only be judged from the consistency of the mass after treatment,
and it is just this that renders the process of little value. The cacao
material issuing from the machine must be just as liquid as when it
comes out of the triturating mills, and so long as it appears as a
glucose substance, which very often happens where unsuitable mixing
machines are employed, so surely will it contain water, and this may
lead to the growth of mould or to the cacao developing a grey colour
when packed in boxes. If the cacao cannot be sufficiently dried in
these machines, it must be transferred to some sort of drying plant
(where the temperature is about 48 ° C.), and there deprived of its
still remaining moisture.
When volatile alkali is used, kneading and mixing machines cannot very
well be dispensed with, as they work up the cacao material much more
thoroughly and admit of a better distribution of the ammonia than the
melangeur or incorporator. In this case it is advisable that the entire
process be carried out in some apartment separated from the other rooms
of the factory, in order that the pungent smell of ammonia may not
be communicated to other products, a further evil connected with this
method of disintegration. At the same time provision must be made for
the escape of the discharged gas through flues leading out into the
open air.[131]
The treated cacao, when perfectly free from water and volatile
alkali, then passes on to the press, pulveriser and sifting machine
successively, the several operations being proceeded with exactly
as described. In the original process of Rüger’s, the defatted and
disintegrated cacao is dried after it has been reduced to smaller
pieces, and then mixed with fat in such proportions as seem requisite
and desirable, so that it is possible in this method to re-imbue a
disintegrated cacao with its original percentage of fatty contents.
2. ~Disintegration after Pressing.~
In this process, which may no longer be adopted as far as we can
ascertain the mechanically prepared beans are roasted, crushed and
decorticated, then ground in mills, defatted, and finally the cakes
are broken up into a rough powder and treated with alkali in the
manner above described. Care must here be taken to use as little water
as possible in dissolving the alkali. It is best to employ potash
exclusively, for it has been found that the last traces of volatile
alkali are extremely difficult to remove from defatted cacaos as
decomposed by the solution, and there is no means of neutralising the
ammonia without at the same time causing material damage to the flavour
and aroma of the product treated.
The concentrated solution of alkali may be conveniently sprayed on
the powder while the latter is subjected to a constant stirring, an
operation best effected in the melangeur. The final drying is carried
out in hot closets, provided with an effective ventilator suitable
to the purpose. After it has been thoroughly dried, the cacao next
succeeds to the pulverising and sifting processes.
Some methods of rendering cacao soluble remain to be mentioned,
wherein no alkali whatever is used, and in which the disintegration is
effected by means of either water or steam. The first process of the
kind was invented by Lobeck & Co of Dresden[132] in the year 1883. The
cacao beans, either raw, roasted, decorticated, ground or otherwise
mechanically treated are exposed to heat and the action of steam under
high pressure in a closed vessel, then subsequently powdered and
dried. The process has little to recommend it and has not been able to
establish itself accordingly, for hereby the starch in the cacao is
gelatinised, and acid fermentation is introduced, such as does not fail
to damage the final product. Then again, there is a danger of the cacao
becoming mouldy in the store rooms, after being treated by this process.
A second method, patented by Gädke, German Patent No. 93 394, 17 th.
Jan. 1895, consists in disintegrating by means of water in a less
practical manner. The roasted, decorticated but as yet unground beans
are moistened with water, and subsequently dried at a temperature of
100 ° C. after which succeed the processes of grinding, defatting,
pulverising and so forth. This process has also failed to establish
itself to any effect.
* * * * *
In our opinion any one of these methods skilfully and properly carried
out will yield a marketable, hygienic and wholesome product, though
some of them can boast of their own particular advantages. This
holds good for the so-called “Dutch” method in particular, though
it is open to the objection that the cacao so prepared is combined
with an extraneous product and that the combination remains right up
to the moment of consumption. Considered from this point of view,
disintegration with fixed alkalis is generally less advisable than
the optional treatment with water or volatile alkali, but it may be
taken for granted that each manufacturer had better decide the several
details best adapted to his own particular outfit.
A well made soluble cocoa powder should have a pure brown colour,
without any suspicion of grey, should be perfectly dry, and feel light
and soft when finely divided, so betraying that property which the
French designate under the term “impalpable The peculiar aroma of
the cacao must be retained, and especially should the preparation be
preserved from the slightest taint of any ammonia combination, its
taste being kept pure and cacao-like, any hint of alkalinity indicating
defect in the manner of disintegration. Over and above delicacy
of aroma and taste, that characteristic described as “solubility”
constitutes a main criterion of quality in the eyes of the consuming
public. To ascertain that only an empirical test can be employed.[133]
About 7·5 grammes of cocoa powder are introduced into some 150 grammes
of hot milk or hot water contained in a graduated beaker, and then the
quantity of sediment which sinks to the bottom of the vessel in a given
time is noted. The more slowly a sediment is formed and the smaller it
is, the greater the “solubility” of the cocoa.
If it becomes necessary to give the cacao an additional flavouring, the
spices or ether-oils generally employed in the manufacture of chocolate
may be used in the course of pulverisation, and shortly before sifting.
C. Packing and Storing of the finished Cacao Preparations.
Chocolate will keep in its original condition for years, when protected
from atmospheric influence. It is therefore generally, and especially
where the finer qualities are concerned, packed up immediately after
it leaves the last process, and ornamented chocolates are previously
varnished with an alcoholic solution of benzoin and shellac (see page
250).
The inferior qualities are usually packed in paper and wooden boxes,
but the superior first in tin-foil and subsequently in paper. ~Cocoa
powder~ arrives packed in parchment boxes as a rule, and also in
cardboard or tin boxes.
Although packing in parchment or waxed paper is hygienically and
economically more advantageous than tin-foil packing, the latter
is nevertheless to be preferred, not only because it is a better
preservative of the aroma evident in the spices added, but also because
it prevents an evil which also in the end leaves its mark on cacao,
when stored a very long time, to wit, the development of rancidity.
This is explained by the fact that the tin-foil sticks to the
chocolate, and so hinders the penetration of air.
According to an act dating from June 25th. 1897, and in force in
Germany (Reichsgesetzblatt No. 22), metal-foil containing more than
one percent of lead may not be used in the packing of snuff, chewing
tobacco and cheese. What holds good for other articles of consumption
must also apply to cacao preparations, when they are so packed that
they come first of all into contact with metal-foil, and not with
paper. Tin-plating also, containing in its coating more than 1 % of
lead and in the soldering more than 10 % is also inadmissible in the
chocolate industry. Although it is said that the whole of the tin-plate
fittings made in Germany are constructed according to an imperial
standard, yet it may occasionally so happen that cheap packing material
does not correspond and answer to the legal requirements.
The manufacturer can only protect himself against possible prosecution
for contravening or neglecting the articles of this act by obtaining a
written guarantee as to the quality of the tin-plate supplied.
The rooms where chocolate wares are stored should not be too warm,
and it is indispensable that they be kept dry, for heat accelerates
the volatilisation of their aroma and also the rancidity to which
cacao is liable, whilst moisture spoils the general appearance of the
chocolate and promotes the growth of mould. This development of mould,
which is first noticeable after long storage in damp, dark warehouses,
is principally due to the growth of a fungus which Royer has named
“Cacao-oïdium[134]
As the numerous wrappings (in tin-foil, paper, etc.) are at present
only effected by hand labour, they mean an appreciable increase in the
price of the goods. This is of less moment for the chocolate tablets as
the small napolitains and the like. Therefore attempts have often been
made to effect this wrapping by means of machines[135], and I have seen
among others two models for napolitains, one on a large and the other
on a small scale, the property of a Hamburg chocolate factory, and
constructed by the firm of A. Savy & Co., Paris, which same machines
were said to effect the wrapping in tin-foil, folding and additional
packing in paper, as also the final closing, automatically and well;
but just as I requested to be shown the machines, I was told that they
were for the time being not in working order. Since then I have heard
no more of the matter, and regret that the firm of Savy & Co., who have
a branch in Dresden, have not been able to answer several letters which
I sent them inquiring for further particulars. It must be that the
machines have failed to answer their purpose, for otherwise they would
have been assured of a hearty reception, no matter how dear they might
have been. So for the nonce our chocolate packing must depend on hand
labour.
Quite a different arrangement obtains in respect to cocoa powder, which
was also originally packed up in paper bags by hand. This operation
is to-day despatched in machines, as also in the case of other powder
substances, like tooth-powder, dyes, patent foods, soap powder, etc.,
and this even in the smallest of factories. It is true that the machine
built a decade ago by L. Wagner in Heilbronn and at that time described
by Zipperer in our second edition, which was to wrap up a dozen packets
simultaneously, seems to have failed, for it is no longer constructed;
yet its place has been taken by a succession of other machines which
have stood the tests of many years. The principle has been altered,
many packets at one time not being filled, but always one only, and the
advantage lies in the fact that the machine fills more exactly and with
a higher degree of uniformity as regards the weights of the several
packets.
[Illustration: Figs. 92 and 93.]
Apart from the “Machines for packing en masse” Co., Ltd. Berlin, who
put out several automatic fillers, special mention may here be made of
the firm of Fritz Kilian, whose automatic filler and packer “Ideal”
(fig. 92) for quantities of from 25-2500 grammes, and “Triumph” (fig.
93), for quantities of from 1-100 grammes, have both long established
their right to a place in every factory, their excellence being
predominant.
FOOTNOTES:
[105] See Mitscherlich, page 111.
[106] Practical Guide to Chocolate Manufacture (no date given).
[107] Comptes rendus de l’Exposition, quoted by B. de la Roque.
[108] Gordian, A., German Chocolate and Sugar Industries, Vol. 1, p. 22.
[109] Correspondence of the Association of German Chocolate
Manufacturers 1878, p. 17.
[110] Correspondence of Ass. German Chocolate Manufacturers 1891, No. 5.
[111] Ibid 1891, No. 7.
[112] Zeitschrift für öffentliche Chemie 1898, p. 810.
[113] The determining of the fibre is reached by the Weender method.
[114] For that purpose boxes with handles and having a capacity of
from 10½ to 60 litres are employed, as well as the portable troughs
previously mentioned. The transport of the chocolate mass also takes
place in boxes made of compressed steel plates (Siemens-Martin),
galvanised or otherwise, e. g. as manufactured by the Stamp and Press
Works at Brackwede near Bielefeld. The firm of A. Reiche and others
also make similar boxes.
[115] Muspratt Encyclop. Handbuch der techn. Chemie. Vol. IV, p. 190,
1902.
[116] This description is taken from Muspratt, Encycl. Handb. d. Techn.
Chemie, Vol. IV, p. 1808 and Mitscherlich: Der Kakao u. die Schokolade
p. 115.
[117] Constructed by A. Reiche, Sheet Iron Works in Dresden-Plauen.
[118] German patent No. 62784.
[119] Villon-Guichard, Dictionnaire de Chimie industrielle, Vol. 1
Chocolat.
[120] Should such rooms eventually be insulated, the best material for
this operation are “Corkstone Plates”, as manufactured by various firms
(e. g. Korkstein-Werke Coswig i. Sa., etc.).
[121] This extensive employment of cacao butter in the preparation of
covering material on the one hand, and on the other the consequently
increased cost of chocolates rich in fat, have hitherto proved the
chief objection to the preparation of cocoa powder deficient in fatty
contents, which we shall discuss later.
[122] D.R.P. No. 66606.
[123] D.R.P. 74260 of Sept. 3rd. 1893.
[124] D.R.P. No. 178897, of July 15th, 1904 (reg. 15th Nov. 1908).
[125] This however, is true only to a certain degree, comp. Neumann,
The Use of Cacao as a Food Preparation, Munich & Berlin 1906, pag. 97
ff.
[126] cf. Z.U.N.G. 1900, vol. 18 p. 171.
[127] See enactments of the 16.9.1907 and 10.11.1909 (Coburg): Notices
of the Association of German Chocolate Makers XXX, No. 1 21.9.1909,
pag. 1.
[128] Cf. Z.U.N.G., Bd. 18 Nos. 1 and 2 (1909) p. 178.
[129] Eng. Patent No. 20436, 24. 11. 1891.
[130] The potash now generally in use is prepared from the carbon of
residuary molasses, and is technically considered, very pure. It is
supplied by Dr. Hensel & Co., Blumenthal (Hanover).
[131] The special model of the Universal Mixer and Kneader has for this
purpose (apart from the metal lid shutting down air-tight) a steam
drain pipe, which is fitted with a ventilator and led into the open, so
that the vapours and chemical exhalations can escape without causing
any damage.
[132] German Patent No. 30 894. See also Chemiker-Zeitung 1886, p. 1431.
[133] Cf. R. O. Neumann, loc. cit. page 98 and following pages.
[134] Beckurts Pharmac. Jahresbericht 1883-84, p. 990.
[135] The “Machines for packing en masse” Co. Ltd. Berlin, have
recently strongly recommended their “wrapping machines, for centres of
any shape or consistency, which work automatically, that is to say,
it is only necessary to heap the centres in continuous succession in
the machine, when they are urged forward and wrapped in paper or other
materials, being finally despatched out of the machine automatically.
The wrappers may be simple or double, loose, or tight fitting.”
Their employment in the packing of chocolate tablets is especially
recommended.—And so the problem would be solved! Unfortunately I am
in want of personal guidance, never yet having seen the machines in
working order, and so not being able to submit any opinion as to their
efficiency. Even if they are really able to deal with larger tablets,
yet the more critical problem regards the smaller goods, especially in
connection with the wrapping in tin-foil.
+Part III.+
Ingredients used in the manufacture of chocolate.
A. Legal enactments. Condemned ingredients.
Chocolate is a mixture of cacao mass with sugar, to which usually
spices and even cacao butter are also added. The sugar generally
amounts to rather more than one half (60 percent) of the total
mixture. Spices such as cinnamon, vanilla, cloves, nutmeg, mace,
cardamoms, as well as cacao butter, or perfumes like peruvian balsam,
are only added in small quantity so as to improve or alter the flavour
as required. Recently, the ethereal oils of the spices have been used
for this purpose as well as artificially prepared aromatic substances,
such as vanillin, for example. Flour and starch[136], although the
latter is seldom used, are permissible ingredients in cheaper kinds of
chocolate but only when the fact of the addition is plainly stated.
The kinds of flour usually employed are wheat and potato flours,
rice-starch and arrowroot, dextrin and, less frequently, oat, barley,
acorn, chestnut, or rye flour. In certain forms of dietetic chocolate,
sugar being injurious to invalids, it is replaced by saccharin; another
material, such as a leguminous flour from beans, peas or lentils,
must be employed in its place.[137] In some kinds of fancy chocolate,
harmless colours, tincture of benzoin etc. are used.
B. Ingredients allowed
I. Sweet Stuffs.
a) Sugar.
Both cane and beetroot sugar are employed in the manufacture of
chocolate. As this naturally possesses a brownish colour, brownish
white as well as white sugar is used for mixing with the cacao mass.
The kinds of sugar used are:
1. Sugar dust, a white crystallisable and very fine powder.
2. Crystal or granulated sugar, consisting of loose, plain crystals,
and suitable for almost all purposes in the manufacture.
3. Sugar flour I, II, and III which is a difficultly crystallisable
sugar containing an amount of molasses increasing with the number, and
it is of a more or less brown colour.
[Illustration: Fig. 94.]
The chocolate manufacturer nevertheless requires the sugar to answer to
certain characters. It must dissolve in half its weight of warm water
forming a sweet syrup. The syrup must have no action on either red or
brown litmus paper i. e. have neither acid nor alkaline reaction, and
on no account coagulate boiling milk.
The sugar is usually added to the cacao mass in the form of a very fine
powder and sometimes in a coarser condition, though that is not to be
recommended. By using finely powdered sugar, the rolling of the cacao
mass is considerably facilitated and the manufacture is accelerated.
The sugar must be perfectly dry, as damp sugar yields a dull chocolate
which readily crumbles.
[Illustration: Fig. 95.]
For grinding the sugar, the so called edge-runner mill as shown in
figure 94 was formerly employed.
It is like the melangeur constructed of a firmly fixed bed-stone and
two cylindrical runners.
The pulverised material issuing from such an apparatus must then be
passed through one of the various kinds of sifting machines, where
the finer parts fall through the meshes of a silken sieve, whilst
the rougher are discharged at the end of the arrangement: for small
factories such machines as the drum sifters illustrated in fig. 95, and
for the larger those centrifugal sifters which have already been fully
described.