Cocoa and Chocolate Part 12

As fineness is a very important quality of cocoa, the powder so obtained is very carefully sieved. This is effected by shaking the powder into an inclined rotating drum which is covered with silk gauze. In the cocoa which pa.s.ses through this fine silk sieve, the average length of the individual particles is about 0.001 inch, whilst in first-cla.s.s productions the size of the larger particles in the cocoa does not average more than 0.002 inch. Indeed, the cocoa powder is so fine that in spite of all precautions a certain amount always floats about in the air of sieving rooms, and covers everything with a brown film.

(_l_) _Packing._

The cocoa powder is taken to the packing rooms. Here the tedious weighing by hand has been replaced by ingenious machines, which deliver with remarkable accuracy a definite weight of cocoa into the paper bag which lines the tin. The tins are then labelled and packed in cases ready for the grocer.

CHAPTER VI

THE MANUFACTURE OF CHOCOLATE

Since the great improvements of the steam engine, it is astonis.h.i.+ng 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 Encyclopaedias, 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 ma.s.s 33 parts.

Cacao b.u.t.ter 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 h.o.m.ogeneous ma.s.s, the principles underlying its manufacture are obviously simple, yet when we come to consider the production of a modern high-cla.s.s chocolate we find the processes involved are somewhat elaborate.

(_a_) _Preparing the Nib or "Ma.s.s."_

The nib is obtained in exactly the same way as in the manufacture of cocoa, the beans being cleaned, roasted and sh.e.l.led. 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 "ma.s.s" 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, coa.r.s.e or finely ground, is mixed with the sugar in a kind of edge-runner or grinding-mixer, called a _melangeur_. As is seen in the photo, the _melangeur_ 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 acc.u.mulating at the sides by curved sc.r.a.pers, 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 _melangeur_ with a shovel. The operator rests a shovel lightly on the revolving floor, and the material mounts into a heap upon it.

[Ill.u.s.tration: CHOCOLATE MELANGEUR.

Reproduced by permission of Messrs. Lake. Orr & Coy. Ltd.]

[Ill.u.s.tration: PLAN OF CHOCOLATE MELANGEUR.]

[Ill.u.s.tration: CHOCOLATE REFINING MACHINE.

Reproduced by permission of Messrs. J. Baker & Sons, Willesden.]

(_c_) _Grinding the Mixture._

The mixture is now pa.s.sed 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 pa.s.sing between the rolls, a dry powder--the explanation is that the sugar having been more finely crushed now requires a greater quant.i.ty of cacao b.u.t.ter 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 pa.s.s 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 _melangeur_, where curiously enough the whole becomes once again of the consistency of dough. The grinding between the rolls and the mixing in the _melangeur_ 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.

[Ill.u.s.tration: GRINDING CACAO NIB AND SUGAR.

(Messrs. Cadbury Bros., Bournville).]

[Ill.u.s.tration: 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 b.u.t.ter. In this process the chocolate is put in a vessel shaped something like a sh.e.l.l (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 quant.i.ties 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, ca.s.sia, 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.

[Ill.u.s.tration: "CONCHE" MACHINES.

Reproduced by permission of Messrs. J. Baker & Sons, Willesden.]

[Ill.u.s.tration: SECTION THROUGH "CONCHE" MACHINE.]

[Ill.u.s.tration: MACHINES FOR MIXING OR "CONCHING" CHOCOLATE.]

(_f_) _Moulding._

Small quant.i.ties of cacao b.u.t.ter 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 _melangeur_ or the conche) to the moulding rooms. Before moulding, the chocolate is pa.s.sed 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 ma.s.s 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.

[Ill.u.s.tration: CHOCOLATE SHAKING TABLE.]

The most important factor in obtaining a good appearance is the temperature, and chocolate is frequently pa.s.sed 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 b.u.t.ter is about 32 C, it will be realized that the b.u.t.ter is super-cooled and is ready to crystallize on the slightest provocation. Each mould has to contain the same quant.i.ty 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 b.u.mp. 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 pa.s.ses 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.