THE MANUFACTURE OF CHOCOLATE
Since the great improvements of the steam engine, it is
astonishing to what a variety of manufactures this useful
machine has been applied: yet it does not a little excite our
surprise that one is used for the trifling object of grinding
chocolate.
It is, however, a fact, or at least, we are credibly
informed, that Mr. Fry, of Bristol, has in his new
manufactory one of these engines for the sole purpose of
manufacturing chocolate and cocoa.
_Berrow's Worcester Journal,_ June 7th, 1798.
What I am about to write under this heading will only be of a general
character. Those who require a more detailed exposition are referred to
the standard works given at the end of the chapter. In these, full and
accurate information will be found. The information published in modern
Encyclopædias, etc., concerning the manufacture of chocolate is not
always as reliable as one might expect. Thus it states in Jack's
excellent _Reference Book_ (1914) that "Chocolate is made by the
addition of water and sugar." The use of water in the manufacture of
chocolate is contrary to all usual practice, so much so that great
interest was aroused in the trade some years ago by the statement that
water was being used by a firm in Germany.
SPECIMEN OUTLINE RECIPE.
Ingredients required for _plain eating-chocolate_.
Cacao nib or mass 33 parts.
Cacao butter 13 "
Sugar 53-3/4 "
Flavouring 1/4 "
-------------
100 parts
Since eating-chocolate is produced by mixing sugar and cacao nib, with
or without flavouring materials, and reducing to a fine homogeneous
mass, the principles underlying its manufacture are obviously simple,
yet when we come to consider the production of a modern high-class
chocolate we find the processes involved are somewhat elaborate.
(_a_) _Preparing the Nib or "Mass."_
The nib is obtained in exactly the same way as in the manufacture of
cocoa, the beans being cleaned, roasted and shelled. The roasting,
however, is generally somewhat lighter for chocolate than for cocoa. The
nibs produced may be used as they are, or they may be first ground to
"mass" by means of mill-stones as described above.
(_b_) _Mixing in the Sugar._
Some makers use clear crystalline granulated sugar, others disintegrate
loaf sugar to a beautiful snow-white flour. The nib, coarse or finely
ground, is mixed with the sugar in a kind of edge-runner or
grinding-mixer, called a _mélangeur_. As is seen in the photo, the
_mélangeur_ consists of two heavy mill-stones which are supported on a
granite floor. This floor revolves and causes the stationary mill-stones
to rotate on their axes, so that although they run rapidly, like a man
on a "joy wheel," they make no headway. The material is prevented from
accumulating at the sides by curved scrapers, which gracefully deflect
the stream of material to the part of the revolving floor which runs
under the mill-stones. Thus the sugar and nib are mixed and crushed. As
the mixture usually becomes like dough in consistency, it can be neatly
removed from the _mélangeur_ with a shovel. The operator rests a shovel
lightly on the revolving floor, and the material mounts into a heap upon
it.
[Illustration: CHOCOLATE MELANGEUR.
Reproduced by permission of Messrs. Lake. Orr & Coy. Ltd.]
[Illustration: PLAN OF CHOCOLATE MELANGEUR.]
[Illustration: CHOCOLATE REFINING MACHINE.
Reproduced by permission of Messrs. J. Baker & Sons, Willesden.]
(_c_) _Grinding the Mixture._
The mixture is now passed through a mill, which has been described as
looking like a multiple mangle. The object of this is to break down the
sugar and cacao to smaller particles. The rolls may be made either of
granite (more strictly speaking, of quartz diorite) or of polished
chilled cast iron. Chilled cast iron rolls have the advantage that they
can be kept cool by having water flowing through them. A skilled
operator is required to set the rolls in order that they may give a
large and satisfactory output. The cylinders in contact run at different
speeds, and, as will be seen in the diagram, the chocolate always clings
to the roll which is revolving with the greater velocity, and is
delivered from the rolls either as a curtain of chocolate or as a spray
of chocolate powder. It is very striking to see the soft
chocolate-coloured dough become, after merely passing between the rolls,
a dry powder--the explanation is that the sugar having been more finely
crushed now requires a greater quantity of cacao butter to lubricate it
before the mixture can again become plastic. The chocolate in its
various stages of manufacture, should be kept warm or it will solidify
and much time and heat (and possibly temper) will be absorbed in
remelting it; for this and other reasons most chocolate factories have a
number of hot rooms, in which the chocolate is stored whilst waiting to
pass on to the next operation. The dry powder coming from the rolls is
either taken to a hot room, or at once mixed in a warm _mélangeur_,
where curiously enough the whole becomes once again of the consistency
of dough. The grinding between the rolls and the mixing in the
_mélangeur_ are repeated any number of times until the chocolate is of
the desired fineness. Whilst there are a few people who like the clean,
hard feel of sugar crystals between the teeth, the present-day taste is
all for very smooth and highly refined chocolate; hence the grinding
operation is one of the most important in the factory, and is checked at
the works at Bournville by measuring with a microscope the size of the
particles. The cost of fine grinding is considerable, for whilst the
first breaking down of the cacao nibs and sugar crystals is
comparatively easy, it is found that as the particles of chocolate get
finer the cost of further reduction increases by leaps and bounds. The
chocolate may now proceed direct to the moulding rooms or it may first
be conched.
[Illustration: GRINDING CACAO NIB AND SUGAR.
(Messrs. Cadbury Bros., Bournville).]
[Illustration: SECTION THROUGH CHOCOLATE GRINDING ROLLS.]
(_d_) _Conching._
We now come to an extraordinary process which is said to have been
originally introduced to satisfy a fastidious taste that demanded a
chocolate which readily melted in the mouth and yet had not the cloying
effect which is produced by excess of cacao butter. In this process the
chocolate is put in a vessel shaped something like a shell (hence called
a _conche_), and a heavy roller is pushed to and fro in the chocolate.
Although the conche is considered to have revolutionized the chocolate
industry, it will remain to the uninitiated a curious sight to see a
room full of machines engaged in pummelling chocolate day and night.
There is no general agreement as to exactly how the conche produces its
effects--from the scientific point of view the changes are complex and
elusive, and too technical to explain here--but it is well known that if
this process is continued for periods varying according to the result
desired from a few hours to a week, characteristic changes occur which
make the chocolate a more mellow and finished confection, having more or
less the velvet feel of _chocolat fondant_.
(_e_) _Flavouring._
Art is shown not only in the choice of the cacao beans but also in the
selection of spices and essences, for, whilst the fundamental flavour of
a chocolate is determined by the blend of beans and the method of
manufacture, the piquancy and special character are often obtained by
the addition of minute quantities of flavourings. The point in the
manufacture at which the flavour is added is as late as possible so as
to avoid the possible loss of aroma in handling. The flavours used
include cardamom, cassia, cinnamon, cloves, coriander, lemon, mace, and
last but most popular of all, the vanilla pod or vanillin. Some makers
use the choice spices themselves, others prefer their essential oils.
Many other nutty, fragrant and aromatic substances have been used; of
these we may mention almonds, coffee, musk, ambergris, gum benzoin and
balsam of Peru. The English like delicately flavoured confections,
whilst the Spanish follow the old custom of heavily spicing the
chocolate. In ancient recipes we read of the use of white and red
peppers, and the addition of hot spices was defended and even
recommended on purely philosophical grounds. It was given, in the
strange jargon of the Peripatetics, as a dictum that chocolate is by
nature cold and dry and therefore ought to be mixed with things which
are hot.
[Illustration: "CONCHE" MACHINES.
Reproduced by permission of Messrs. J. Baker & Sons, Willesden.]
[Illustration: SECTION THROUGH "CONCHE" MACHINE.]
[Illustration: MACHINES FOR MIXING OR "CONCHING" CHOCOLATE.]
(_f_) _Moulding._
Small quantities of cacao butter will have been added to the chocolate
at various stages, and hence the finished product is quite plastic. It
is now brought from the hot room (or the _mélangeur_ or the conche) to
the moulding rooms. Before moulding, the chocolate is passed through a
machine, known as a compressor, which removes air-bubbles. This is a
necessary process, as people would not care to purchase chocolate full
of holes. As in the previous operations, every effort has been made to
produce a chocolate of smooth texture and fine flavour, so in the
moulding rooms skill is exercised in converting the plastic mass into
hard bars and cakes, which snap when broken and which have a pleasant
appearance. Well-moulded chocolate has a good gloss, a rich colour and a
correct shape.
[Illustration: CHOCOLATE SHAKING TABLE.]
The most important factor in obtaining a good appearance is the
temperature, and chocolate is frequently passed through a machine
(called a tempering machine) merely to give it the desired temperature.
A suitable temperature for moulding, according to Zipperer, varies from
28° C. on a hot summer's day to 32° C. on a winter's day. As the melting
point of cacao butter is about 32° C, it will be realized that the
butter is super-cooled and is ready to crystallize on the slightest
provocation. Each mould has to contain the same quantity of chocolate.
Weighing by hand has been abandoned in favour of a machine which
automatically deposits a definite weight, such as a quarter or half a
pound, of the chocolate paste on each mould. The chocolate stands up
like a lump of dough and has to be persuaded to lie down and fill the
mould. This can be most effectively accomplished by banging the mould up
and down on a table. In the factory the method used is to place the
moulds on rocking tables which rise gradually and fall with a bump. The
diagram will make clear how these vibrating tables are worked by means
of ratchet wheels. Rocking tables are made which are silent in action,
but the moulds jerkily dancing about on the table make a very lively
clatter, such a noise as might be produced by a regiment of mad cavalry
crossing a courtyard. During the shaking-up the chocolate fills every
crevice of the mould, and any bubbles, which if left in would spoil the
appearance of the chocolate, rise to the top. The chocolate then passes
on to an endless band which conducts the mould through a chamber in
which cold air is moving. As the chocolate cools, it solidifies and
contracts so that it comes out of the mould clean and bright. In this
way are produced the familiar sticks and cakes of chocolate. A similar
method is used in producing "Croquettes" and the small tablets known as
"Neapolitans." Other forms require more elaborate moulds; thus the
chocolate eggs, which fill the confectioners' windows just before
Easter, are generally hollow, unless they are very small, and are made
in two halves by pressing chocolate in egg-shaped moulds and then
uniting the two halves. Chocolate cremes, caramels, almonds and, in
fact, fancy "chocolates" generally, are produced in quite a different
manner. For these _chocolats de fantaisie_ a rather liquid chocolate is
required known as covering chocolate.
SPECIMEN OUTLINE RECIPE.
Ingredients required for _chocolate for covering cremes_, etc.:
Cacao nib or mass 30 parts
Cacao butter 20 "
Sugar 49-3/4 "
Flavouring 1/4 "
-------------
100 parts
It is prepared in exactly the same way as ordinary eating chocolate,
save that more butter is added to make it flow readily, so that in the
melted condition it has about the same consistency as cream. The
operations so far described are conducted by men, but the covering of
cremes and the packing of the finished chocolates into boxes are
performed by girls. Covering is light work requiring a delicate touch,
and if, as is usual, it is done in bright airy rooms, is a pleasant
occupation.
[Illustration: GIRLS COVERING, OR DIPPING, CREMES, ETC.
(Messrs. Cadbury Bros., Bournville.)]
The girl sits with a small bowl of warm liquid chocolate in front of
her, and on one side the "centres" (cremes, caramels, ginger, nuts,
etc.) ready for covering with chocolate. The chocolate must be at just
the right temperature, which is 88 °F., or 31° C. She takes one of the
"centres," say a vanilla creme, on her fork and dips it beneath the
chocolate. When she draws it out, the white creme is completely covered
in brown chocolate and, without touching it with her finger, she deftly
places it on a piece of smooth paper. A little twirl of the fork or
drawing a prong across the chocolate will give the characteristic
marking on the top of the chocolate creme. The chocolate rapidly sets to
a crisp film enveloping the soft creme. There are in use in many
chocolate factories some very ingenious covering machines, invented in
1903, which, as they clothe cremes in a robe of chocolate, are known as
"enrobers"; it is doubtful, however, if the chocolates so produced have
even quite so good an appearance as when the covering is done by hand.
[Illustration: THE ENROBER.
A machine for covering cremes, etc., with chocolate.
Reproduced by permission of Messrs. Savy Jeanjean & Co., Paris.]
It would be agreeable at this point to describe the making of cremes
(which, by the way, contrary to the opinion of most writers, contain no
cream or butter), and other products of the confectioner's art, but it
would take us beyond the scope of the present book. We will only remind
our readers of the great variety of comestibles and confections which
are covered in chocolate--pistachio nut, roasted almonds, pralines,
biscuits, walnuts, nougat, montelimar, fruits, fruit cremes, jellies,
Turkish delight, marshmallows, caramels, pine-apple, noisette, and other
delicacies.
[Illustration: A CONFECTIONERY ROOM AT MESSRS. CADBURY'S WORKS AT
BOURNVILLE.
Cutting almond paste by hand moulds.]
_Milk Chocolate._
We owe the introduction of this excellent food and confection to the
researches of M.D. Peter of Vevey, in Switzerland, who produced milk
chocolate as early as 1876. Many of our older readers will remember
their delight when in the eighteen nineties they first tasted Peter's
milk chocolate. Later the then little firm of Cailler, realising the
importance of having the factory on the very spot where rich milk was
produced in abundance, established a works near Gruyères. This grew
rapidly and soon became the largest factory in Switzerland. The sound
principle of having your factory in the heart of a milk producing area
was adopted by Cadbury's, who built milk condensing factories at the
ancient village of Frampton-on-Severn, in Gloucestershire, and at
Knighton, near Newport, Salop. Before the war these two factories
together condensed from two to three million gallons of milk a year.
Whilst the amount of milk used in England for making milk chocolate
appears very great when expressed in gallons, it is seen to be very
small (being only about one-half of one per cent.) when expressed as a
fraction of the total milk production. Milk chocolate is not made from
milk produced in the winter, when milk is scarce, but from milk produced
in the spring and summer when there is milk in excess of the usual
household requirements, and when it is rich and creamy. The importance
of not interfering with the normal milk supply to local customers is
appreciated by the chocolate makers, who take steps to prevent this. It
will interest public analysts and others to know that Cadbury's have had
no difficulty in making it a stipulation in their contracts with the
vendors that the milk supplied to them shall contain at least 3.5 per
cent. of butter fat, a 17 per cent. increase on the minimum fixed by
the Government.
[Illustration: FACTORY AT FRAMPTON, GLOUCESTERSHIRE, AT WHICH MILK IS
EVAPORATED FOR MILK CHOCOLATE MANUFACTURE.
(Messrs. Cadbury Bros., Ltd.).]
SPECIMEN OUTLINE RECIPE.
Ingredients required for _milk chocolate_:
Cacao nib or mass (from 10 to 20 per cent.), say 10
Cacao Butter 20
Sugar 44-3/4
Milk solids (from 15 to 25 per cent.), say 25=(200 parts
of milk.)
Flavouring 1/4
--------
100
Milk chocolate consists of an intimate mixture of cacao nib, sugar and
milk, condensed by evaporation. The manner in which the milk is mixed
with the cacao nib is a matter of taste, and the art of combining milk
with chocolate, so as to retain the full flavour of each, has engaged
the attention of many experts. At present there is no general method of
manufacture--each maker has his own secret processes, which generally
include the use of grinding mills, _mélangeurs_, conches, moulding
machines, etc., as with plain chocolate. We cannot do better than refer
those who wish to know more of this, or other branch of the chocolate
industry, to the following English, French and German standard works on
Chocolate Manufacture:
_Cocoa and Chocolate, Their Chemistry and Manufacture_, by R.
Whymper (Churchill).
_Fabrication du Chocolat_, by Fritsch (Scientifique et
Industrielle).
_The Manufacture of Chocolate_, by Dr. Paul Zipperer (Spon).