which is capable of turning out a much larger quantity of material with
a relatively smaller expenditure of power. The operation of mixing
chocolate is not a mere mixing, for the ~pressure~ exerted by
the ~runners~ is also an indispensable factor. On that account
the ordinary mixing machines have not proved serviceable, especially
in the case of chocolates containing a small amount of fat, such as
the cheaper kinds, while the addition of cacao butter to facilitate
the working of the machine would considerably increase the cost of
production. Melangeurs are generally constructed on the same principle
as the edge runner grinding mills which are so much used; but they
differ from them in so far as the bed-stone revolves, while the runners
merely rotate on their axles without revolving.
[Illustration: Fig. 30.]
The melangeur with travelling bed-stone, as constructed by Lehmann, is
shown at fig. 30; it is fitted with an arrangement for lifting out the
runners.
[Illustration: Fig. 31.]
The bed-stone as well as the runners are made of granite. Each runner
has an axis working in plummer blocks, so that it can be lifted out
independently of the other one. By that construction the runners are
prevented from taking an oblique position as was the case with the
mills formerly made, since one runner would be forced downwards or
tilted on its outer edge whenever the other one was raised up somewhat.
The bed-stone of this machine revolves and it is easily heated by steam
pipes from below. One important advantage of this machine is that
being low it can be very easily charged and emptied. The contrivance
for lifting out the runners prevents them thumping upon the bed-stone
that might otherwise readily happen when starting the machine, and it
also lessens the wear of the driving bands; moreover, large lumps of
sugar or cacao are very readily crushed down and, so, the working is
much facilitated. The emptying of the melangeur is readily and safely
effected, while the bed stone is revolving, by holding a shovel so
that the cacao is thrown up against the shovel. A melangeur of this
construction is represented by fig. 31; it has three runners and
underneath the bed-stone is fitted a steam engine which supplies
driving power, the exhaust steam being used for heating the machine.
Although this emptying by hand is not attended with any serious
drawbacks, yet it involves loss of time and is rather inconvenient,
so that the demand for mechanical automatism in this operation was
very considerable. It is now some years since Messrs. J. M. Lehmann
patented an apparatus for the mechanical discharging of the chocolate
mass from these machines, but their invention still holds good. A
melangeur provided with such apparatus is shown on fig. 31. Here
a vertically moving shovel is sunk behind the outlet, gradually
damming the material, and causing it to rise above the edge of the
tank and fall through the opening. A second but horizontally working
arrangement, which in this case as in the last is controllable by means
of a crank, conducts the remainder of the material to the same shovel.
So the material is discharged within a few minutes.—These melangeurs
are built for varying outputs. Fig. 32 illustrates one of the largest
yet constructed. Its base has a diameter of 2 metres, and the machine
itself has a capacity of 5 cwts. To avoid the mixing of dust with
the sugar as far as possible, the whole melangeur is provided with a
dust-proof protector.
b) Levigation.
An extreme fineness and homogeneity of the chocolate mass is obtained
in the employment of cylindrical rolling machines, for the construction
of which we are indebted to G. Hermann of Paris. Every kind of
chocolate must be passed through the rolling machine at least once
or twice even when finely powdered sugar is used, though in this
case it is less a question of sub-division than of incorporation and
intermixture. The best qualities are passed through the machine from
six to eight times, or even more. The mass is finally fed into the
machine in cold blocks and so ground off. Granite is the material
chiefly employed in making the rollers, although it is not every
variety which can be adapted to this purpose. Apart from the fact that
granite, or indeed any other mineral stone, seldom occurs in compact
masses and free from flaws, neither porphyry nor the stone generally
described as granite is suitable for employment in the construction of
mill rollers. A kind is generally preferred which intermediates between
granite and porphyry as to hardness and possesses excellent grinding
capacities, and which goes by the name of diorite. No other stone can
compare with this diorite in respect to the above qualities, and the
chief firms engaged in the construction of roller machines possess
their own quarries. But we shall return to this later, for recently
experiments with case-hardened casting rollers (Krupp steel) and hard
porcelain have yielded very flattering results.
[Illustration: Fig. 32.]
[Illustration: Fig. 33 a.]
[Illustration: Fig. 33 b.]
We shall now enter into more detail respecting the principle
illustrated by these rolling machines. The plasticity of the chocolate
mass necessitates a rotation of the cylinder surfaces in opposite
directions with dissimilar velocities. Accordingly two or more rollers
are caused to work against each other, and in compliance with this
principle of sub-division with differential velocities, their axles are
fitted with wheels, of which each has a different number of cogs.
So those rollers furnished with the greater number of teeth revolve
more slowly, whilst in opposite instances there is a corresponding
acceleration.
[Illustration: Fig. 34.]
The construction of the machines now in use differs more or less from
that of the type first invented by Hermann, plan and elevation of which
appear in figs. 33 a and 33 b respectively.[116]
The granite rollers at _a¹_, _a²_, _a³_ are fitted with an octagonal
iron axle that is somewhat thicker at the interior part and they are
mounted upon a frame as shown in the drawing. The sockets of the
central rollers _a²_ are fixed and each one is held in position by
three sets screws; those of the two other rollers can be shifted along
grooves in the frame and when the cylinders _a¹_ and _a³_ have been
brought into proper position relatively to the cylinder _a²_ they are
held fast by the set screws _p_.
[Illustration: Fig. 35.]
[Illustration: Fig. 36.]
For the purpose of this adjustment, there is at each end of the machine
a horizontal wrought iron shaft _f_ that can be turned by the winch
_e_, and these shafts are fitted with two endless screws _d_ working
in the corresponding wheels _c_. These occur on the spindles _a_,
which screw in and out of the bearing blocks of the rollers _a¹_ and
_a²_, but turn only in the fixed collars _b_ without being shifted
from their place. The result is that on turning the cranks _e_ the
corresponding cylinder _a¹_ or _a³_ is moved nearer to, or further
from, the central cylinder _a²_, while the position of all of them
always remains parallel. The shaft _Q_ is set in motion by the driving
wheel _L_ fitted with the loose wheel _L¹_. It acts first upon the
cog wheel _K_ which works in the larger wheel _J_ on the axle of the
central roller _a²_. That works in the cog wheel _O_ and the wheel _P_
fitted to the roller _a¹_ driving them as well as the wheel _M_ and
the pinion _N_ of the roller _a³_ The result is that the axle _a²_
makes 1¾ revolutions and _a³_ 6⅛ revolutions while _a¹_ in the
same time makes only one revolution.
[Illustration: Fig. 37.]
The cacao or chocolate is supplied to this machine by the hopper _R_
which is placed between the rollers _a¹_ and _a²_. The pasty mass
adhering to the rollers is carried forward by the quicker moving roller
_a²_ and it is ground finer between the rollers _a²_ and _a³_,
after which the material is removed from _a³_ at the outer side by an
adjustable blade _gg_ and then falls down into a receptacle below.
[Illustration: Figs. 38 and 39.]
On the design fig. 34 we see a machine of more modern construction
ready mounted. The receptacle parts of the same are arranged and
connected in full agreement with the above mentioned except that the
motion is effected by the driving power fitted to the machine on the
ground on the left side.
[Illustration: Fig. 40.]
The principle of this roller machine has long been applied in the
building of other types, and we find that these, variously altered,
renovated and improved, are to-day an indispensable equipment in every
chocolate factory. In the following pages we give a description of some
of the best-known constructions of refiner.
The so called battery rolling mills constitute a remarkable innovation.
It is apparent that the more rollers a cylinder machine contains,
and the greater their length and diameter, all the more efficacious
will the working of the machine be. Batteries have accordingly been
constructed, whereby two, three or more roller systems are combined,
one to every three rollers, and rising one above the other, so that
they slant upwards much as shown in Fig. 40.
As the battery rolling mills possessed the disadvantages that they took
up too much room and could not be well fed and regulated, they are
generally replaced by rolling machines of from 6 to 9 rollers, first
constructed by J. M. Lehmann. These rolling machines of 6 to 9 rollers
which we see before us in Figs. 35 and 36 are really systems of 3
rollers fitted one over the other. They therefore take up the room of a
3-roller machine and are quite as easy to work.
[Illustration: Fig. 41 a.]
As will be seen from the design of a nine-roller apparatus, fig. 37,
the chocolate mass descends from one roller system to the other, and
is fine rolled in a third of the time otherwise required, and at
one operation, with corresponding saving of labour. The nine roller
apparatus are provided with landing stage and steps, and fed either by
means of elevators, or from above.
Fig. 38 shows a recent construction, three roller apparatus (case
castings, cf. below) standing vertically, which accordingly takes
up little room. The hopper is low-lying, whilst the discharging
is effected from the upper roller, and accordingly admits of the
occasional use of a somewhat larger size of transport trolley. This
type also occurs with 6-9-12 rollers, as apparent from fig. 39.
[Illustration: Fig. 41 b.]
Whilst these systems were exclusively supplied with rollers made of
granite or hard porcelain up to a few years ago, it has been found
that good results are obtained by the use of cast rollers, and they
have been for some time employed on machines of three, four and five
rollers. (Figs. 38, 40, 41 a-c.) In consequence of the non-porous
surface of these steel rollers, it is possible to grind to a finest
powder, merely in one operation, without passing the chocolate through
the machine several times; and the so-called “Burning” of masses
which have not been properly mixed cannot arise in this case, though
it is true that the apparatus must be provided with water cooling
arrangements to avoid a too excessive heat. They are specially adapted
to the preparation of the more ordinary qualities, and are even
occasionally employed for finer chocolates, for obviously these must be
again submitted to a rolling process, when granite or porcelain rollers
are preferred.
[Illustration: Fig. 41 c.]
For this reason the 6, 9 or even 12 roller mills have been more
discarded since the last grinding process has been performed by granite
rollers (cold process).
In order to avoid the disadvantages of the pulley drive, it is in
certain cases advisable to drive each machine direct from an electric
motor. Fig. 42 illustrates a refining machine driven in this manner.
[Illustration: Fig. 42.]
c) ~Proportions for mixing cacao mass, sugar and spices.~
The relative proportions of cacao, sugar, and spices, as well as of
starch as in the manufacture of the cheaper sorts, vary considerably.
Generally speaking 50 or 60 parts of sugar are added for 50 or 40 parts
of cacao mass; the following are a few formulae applicable for the
production of those kinds of pure chocolate that are most used.
A. Hygienic chocolate.
Cacao mass }
Powdered sugar} equal parts of each.
B. Spiced chocolate.
a)
Cacao mass 4 kg
Sugar 6 kg
Cinnamon 72 g
Cloves 38 g
Cardamoms 16 g
b)
Cacao mass 4 kg
Sugar 6 kg
Cinnamon 130 g
Coriander 8 g
Cloves 88 g
Oil of lemons 2 g
Cardamoms 16 g
c)
Cacao mass 5 kg
Sugar 5 kg
Cloves 80 g
Cinnamon 220 g
Mace 8 g
d)
Cacao mass 5 kg
Sugar 5 kg
Cinnamon 100 g
Vanilla 100 g
or Vanillin 2·5 g
Mace 2 g
Cardamoms 4·2 g
e) ~Spanish spiced chocolate.~
Cacao mass 5 kg
Sugar 5 kg
Cinnamon 116 g
Cloves 50 g
Cardamoms 82 g
Mace 44 g
Vanilla 40 g
or Vanillin 1 g
Oil of lemons 1 g
C. Vanilla chocolates.
a)
Cacao mass 5 kg
Sugar 5 kg
Cinnamon 160 g
Vanilla 50 g
(or Vanillin 1·2 g)
b)
Cacao mass 4½ kg
Sugar 5½ kg
Cinnamon 150 g
Vanillin 1·5 g
c)
Cacao mass 4 kg
Sugar 6 kg
Cinnamon 120 g
Cloves 20 g
Vanillin 1·6 g
The powdered spices as given above may be replaced by corresponding
essential oils, but see page 237 for remarks on this point.
If the chocolates made from beans rich in oil contain too much fat to
mould properly, a small percentage of their constituent cacao mass
can be replaced by cocoa powder made from the same kind of bean,
but defatted, in the case of the finer qualities; and when inferior
varieties are under consideration, the same result may be attained by
a sufficient increase in the proportion of their other constituent,
sugar, as e. g. 55-60 parts of to 45 or 40 parts of cacao mass, so
disturbing the usual equality of the two ingredients mixed together.
Very cheap chocolates in particular are prepared from a smaller
percentage of cacao mass and show a corresponding increase in their
sugar content. But if the sugar exceeds 65 percent, it is no longer
possible to mould these chocolates, and the addition of fresh cacao
butter becomes a necessary preliminary to this operation, cf. also
the first part in section IV. Such varieties would have a composition
somewhat like the following:
Cacao mass 25 parts
Sugar 67 "
Cacao butter 7 "
Spices and vanillin as above 1 "
In the experimental preparation of samples of chocolate mass it is
not advisable to employ large quantities of ingredients, when a
waste of material is bound to ensue, but to begin with mixing small
quantities of one or two kilos. The small Universal Kneading and Mixing
Machines, Patent Werner & Pfleiderer, Type 1, Class BS, can here be
used with advantage. They are specially intended for small outputs and
experimental work; but we shall return to their description later,
after stating that they are furnished with heating apparatus, stuffing
boxes and air-tight lid, and can easily be taken to pieces, greatly
facilitating the removing of the mass.
III. Further Treatment of the Raw Chocolate.
8. ~Manufacture of “Chocolats Fondants”~
[Illustration: Fig. 43.]
Recently the creams sometimes described as in the heading have
enjoyed a vast popularity, and are sold as eatable chocolates in
ever-increasing quantities. As far as can be ascertained, they
were first manufactured in Switzerland, melt readily, and have a
correspondingly large amount of fat, resulting from the addition of
cacao butter, which distinguishes them from ordinary chocolates.
When readily melting chocolates were first introduced, it was a
prevailing opinion that the required property could only be obtained
by increasing the amount of fatty content. Now the excessive evidence
of fat in chocolates is very objectionable, both as regards taste and
digestibility. To avoid this, therefore, the chocolates are treated
mechanically, to attain the required character of readily melting.
The machines used for that purpose are termed “Conches”, because the
trough, in which the chocolate is rubbed into a long cylinder, has
somewhat the shape of a long shell. For the working up of chocolates in
conches, the necessary conditions are;
1. that the chocolate should have been ground perfectly fine,
2. it must contain such an amount of fat as to become glucose on
warming, not indeed so thin as that used as coating material, but
nevertheless softer than the ordinary cake-chocolate of good quality.
[Illustration: Fig. 43 a.]
[Illustration: Fig. 44.]
The machine can be heated by means of steam, hot water pipes, gas or
charcoal stoking, according as they are available in the place of
installation, and the temperature should rise above 70-80° C. for
fondants, and 50° C. for milk chocolates. In factories with water
power or electricity, continuous fondant machines can be worked day
and night, but when only worked during the day, must be kept warm
overnight. Constant tending of the machine is unnecessary, as it works
automatically. After a treatment of from 40-48 hours, the chocolate
attains the requisite character (i.e. it melts readily), and a rounding
off of taste, which are the properties of all good brands. Milk
chocolates can also be advantageously prepared in the conche, as also
covering or coating cacaos of all kinds, which harden considerably in
consequence of this treatment.
Figs. 43 and 43 a show quadruple conches of the modern type with hot
water, wherein four troughs are arranged in pairs, and one opposite the
other. Conches with only 1 and 2 troughs are also constructed, and in
various sizes, the troughs sometimes having a capacity of 125 and 200
kilos, so that the quadruple conche is capable of holding five or eight
hundred kilograms in all. The curved bottom of the troughs, as well as
the rollers fitted in them, are made of granite, and the front wall
strongly bent in at the corner, so that the mass is forced over the
border of the front wall, where there are openings for its discharge
as well. To prevent radiation as far as possible, it is best that the
troughs be walled in, the troughs are either walled. Fig. 44 shows the
room of a modern chocolate factory, with 15 conches.
“Chocolats fondants” are from a gastronomic point of view, the finest
chocolate product on the market, and it is not remarkable that this
branch of the chocolate manufacture has witnessed a considerable
extension, and is likely to extend still more.
9. ~Heating chambers and closets.~
The manufacture of chocolate has been very considerably facilitated
by the introduction of heating chambers and closets, which have now
become an indispensable feature of every factory in the industry. In
these chambers the chocolate which has still to be rolled, as well
as that already submitted to this operation, is stored and kept at a
temperature of 60° C. until it can be further treated (moulded). This
manner of heating involves an appreciable cheapening of the production,
for masses which are dry and apparently require an addition of fat
recover in such a manner during a twenty four hours’ storing in the
heating chambers that such addition becomes unnecessary. But especially
when chill casting rollers are employed, which the mass leaves in a
very dry state, the use of these heating chambers is indispensable.
They should be available in every factory to such an extent as to
find room for the total output of one day, though even twice or three
times this amount might very well be provided for. Closets heated by
steam are best adapted for small factories, such as are illustrated
in Fig. 45. They possess double doors, are walled in, and are capable
of holding from 300-400 kilos of chocolate mass for each metre of
length. Larger factories should furnish themselves with chambers, which
are more open to access and on the walls of which iron shelves can
be introduced, heated by steam pipes arranged underneath. A typical
chamber, measuring 2·8 metres in breadth (including passage) and 5
metres in length would hold about 2,500 kg of chocolate.
[Illustration: Fig. 45.]
10. ~Removal of Air and Division.~
[Illustration: Fig. 46.]
After emerging from the final rolling process, the chocolate is stored
up in heating chambers until it is ready to succeed to the moulding,
prior to which, however, it must be freed from air and cut up into
small portions. Until recently, it usually came next in a melangeur
provided with a dish-shaped bed-stone made of granite, as illustrated
in fig. 46, where it was kneaded and reduced to a uniform plasticity
and heated to the temperature required for moulding. The melangeurs
devoted to this purpose are now superseded by special tempering
machines.
A machine of this recent construction, used for working solid and
semi-liquid material, is shown in fig. 47. The tank intended as a
receptacle for the chocolate mass is in this case made of iron and, to
facilitate cleaning, smooth in the interior. It runs in a water-bath,
the supply in which can be controlled by steam or cold water. The
granite runner is provided with a lifting device, admitting of the
working up of material containing foreign ingredients like nuts, whole
and fine-split.
[Illustration: Fig. 47.]
The mass is taken out of the machine in lumps, and in order that it
may be reduced to a temperature suitable for the removal of air (about
26-32 ° C. on the outside) it is laid to cool on wooden, marble or iron
tables. When this temperature is arrived at, large lumps of chocolate
are introduced either into the air-extracting or the dividing machines.
[Illustration: Fig. 48.]
After the importance of the tempering processes had at length been
recognised, inasmuch as the maintenance of the temperature prescribed
is of immense influence on the chocolate subsequently produced, and it
had on the other hand been ascertained that such machines as described
above could not be absolutely relied upon, for the shaking tables
involve an occasional excess of tempering, the idea of a machine which
should completely and automatically perform this task was finally
conceived. This new machine, given in fig. 48, and already differing
from all other tempering machines in external appearance, ushers in an
entirely fresh process respecting the _modus operandi_ prevailing in
the present manufacture of chocolate, which does not fail to satisfy
the highest expectations. It may be said to work continuously, for no
matter what the temperature of chocolate passing into it may be, the
material leaves the machine at the temperature desired within a lapse
of one minute. According as more or less chocolate has to be turned
over in the moulding department, the machine can be stopped or set
in motion without detriment to its efficacy. Besides this, it cleans
almost automatically, so that a quick change of quality is always
possible. The special virtue of this machine is that it turns out the
material with such a degree of homogeneity as has never before been
known, making moulding at much higher temperatures a possibility. There
is yet another side issue, namely a doubling of the life of the moulds,
and finally, owing to the fact that the often considerable amount of
waste material is done away with in this process, the moulding shop
is spared to some extent. The series of rollers through which the
chocolate passes is maintained at a proper temperature by means of
automatic water apparatus. The daily output of the machine figures at
3000-4000 kilograms. The material is passed on out of this machine to
the dividing and moulding processes.
The necessary extraction of air follows immediately on the tempering
process, for the blades of the scraper then release the chocolate mass
from the rollers in thin layers, between which air penetrates. The
removal of air is effected by machines, an old type of which is shown
in fig. 49 (in front elevation).