[Illustration: PLATE I
The Cacao Tree—Theobroma Cacao, Linné.
Zipperer, Manufacture of Chocolate etc. 3^{rd} edition.
Verlag M. Krayn, Berlin W. 10.]
THE
MANUFACTURE
OF
CHOCOLATE
AND OTHER CACAO PREPARATIONS
BY
DR. PAUL ZIPPERER.
THIRD EDITION
REARRANGED, THOROUGHLY REVISED, AND LARGELY REWRITTEN.
EDITOR
DR. PHIL. HERM. SCHAEFFER
FOOD CHEMIST AND MANAGING DIRECTOR.
WITH 132 ILLUSTRATIONS, 21 TABLES AND 3 PLATES.
[Colophon]
BERLIN W.
VERLAG VON M. KRAYN.
LONDON NEW YORK
E. & F. N. SPON LTD. 1915 SPON & CHAMBERLAIN
PUBLISHERS PUBLISHERS
57 HAYMARKET. 123-125 LIBERTY STREET.
ALL RIGHTS RESERVED.
Rosenthal & Co., Berlin NW.21, Alt-Moabit 105
Preface to the third edition of “The Manufacture of Chocolate” by Dr.
Zipperer.
It is now a decade since the appearance of the last edition, and owing
to continual delays in the compiling of the present volume, the book
has been out of print for several years. These delays ensued because
the editor wished to take into account the most recent determinations
and decrees of the guilds and various legislative factors connected
with the industry; but he was at length forced to the conclusion that
notwithstanding the excellent organisation and lofty standing of the
branch under consideration, it was useless to wait for anything final
and absolute in such a field. Suggestions of possible improvements and
indications of blemishes are therefore earnestly invited, in order
that they may be duly allowed for in the event of a new edition. — The
plan followed by Zipperer has been adopted in the main; a tribute due
to its previous success. Yet on the other hand, the arrangement of the
book has undergone some alteration, and is, at least in the editor’s
opinion, a perceptible improvement. — All scientific, industrial and
technical progress has been treated as fully as possible, the economic
part in particular having been diligently recast.
It would, of course, have been impossible for the editor to write all
these chapters without external aid, his knowledge of the respective
branches being by no means exhaustive enough. He may therefore
be allowed to express here his obligation and thanks to all his
fellow-workers; and in particular, to the ~Association of German
Chocolate Manufacturers~, Dresden; its managing director, Herr
Greiert; the director of the ~Cocoa Purchase Co.~, Hamburg,
Herr Rittscher, who contributed the whole of the chapter headed;
~Commercial Varieties of Cacao Beans~; further to Prof. Dr.
Härtel, Chief Inspector of the Royal Research Institute, Leipsic;
Dr. R. Böhme, Managing Director of Messrs. Stollwerck Bros. Chemical
Laboratory, Cologne; and to Superintendent Engineer Schneider, of
the firm J. M. Lehman, Dresden, among many others. Mention must also
be made of the manufacturers who so kindly placed material at the
editor’s disposal. Let us hope that the work will meet with a success
corresponding to the pains taken by the editor and publishers, and
prove a really serviceable ~Handbook to the Chocolate Industry~.
Dr. Schaeffer.
Extracts from the prefaces to the first and second editions.
The object of this work is to furnish a source of information and
advice for those who are interested in the branch of industry to which
it relates.
The author of this treatise has therefore endeavoured not only to
describe the manufacturing processes; but he has also devoted special
attention to the raw materials employed, and endeavoured to make them
generally familiar by reference to the literature on the subject, as
well as by providing a precise account of the chemical constituents of
these substances and discussing the consequently necessary procedure to
be observed in the course of manufacture. The art of chocolate making
is no longer what it was a few decades ago; it has for the most part
passed from small operators into the hands of large manufacturers. A
short historical resumé will serve as a sketch of this development and
a cursory description of some forms of apparatus which have now merely
historical interest will serve to show how improvement in the industry
has been effected.
Chocolate is a favourite and most important article of food, and in
that sense it is subject to legal regulations for which allowances must
be made, as well as for the most suitable analytical methods by means
of which a manufacturer can ascertain the presence of unlawful mixtures
in competing products, so that knowing the regulations in force, he may
avoid any infringement of the same.
* * * * *
Within the ten years that have elapsed since the first edition of this
work appeared, the manufacture of chocolate has undergone considerable
expansion. Not only has the ~modus operandi~ been simplified
and improved by the introduction of a number of new mechanical
appliances, but the technique of the subject has been so extended,
both from chemical and mechanical points of view, as partly to furnish
a new standard in estimating and determining cacao constituents and
preparations. The author has endeavoured to take due account of all
these advances, and made a point of collecting the material scattered
through the various professional journals, sifting or supplementing
where necessary, in order that all engaged in the industry, ~the
manufacturer as well as the food analyst and the engineer~, may be
in a position to derive a vivid impression of existing conditions in
the chocolate manufacture, from the present volume.
In consideration of the importance which several branches of the
industry have recently acquired, such as the preparation of cocoa
powder, soluble cocoa, cacao butter, pralinés and chocolate creams,
space has been given to descriptions of the respective details. On the
other hand no attempt has been made to introduce calculations as to the
cost of manufacture, since statements to that effect would possibly be
rather detrimental than otherwise.
Costs of production as regards cacao preparations is subject to great
variation, according to the scale on which they are carried out, so
that estimates made on the basis of large operations might eventually
lead to the conclusion that a small factory might be profitable, and
with no better result than that of creating undue competition in prices
and occasioning eventual failure. Moreover, the fluctuations in the
market price of cacao and sugar are so frequent, and there is such
possibility of new sources of expense, that calculations can only apply
to the time when they are made; they soon become out of date, and then
afford no trustworthy indication of probable profit and loss.
The section treating of legislative regulations relating to the trade
in cacao preparations has undergone complete revision to adapt it to
existing conditions.
To render the book more useful, an appendix has been added in which the
production and composition of a few cacao preparations are treated of,
providing valuable data for reference.
Dr. Paul Zipperer.
CONTENTS
First Part: =The Cacao Tree= Page
A. =Tree and Beans= 1
a) Description of the Cacao Tree and its Fruit 1
b) Geographical Distribution and History of the Cacao Tree 4
c) Cultivation of the Cacao Tree; Diseases and Parasites 7
d) Gathering and Fermentation 9
e) Description of the Beans 12
f) The Commercial Sorts of the Cacao Bean 16
1. American Cacao Varieties 19
2. African Cacao Varieties 28
3. Asiatic Cacao Sorts 32
4. Australian Cacao Sorts 33
g) The Trade in Cacao and the Consumption of Cacao Products;
Statistics 33
B. =Chemical Constitution of the Bean= 43
a) The Cacao Bean Proper 43
1. Water or Moisture 49
2. Fat 49
3. Cacao red or Pigment 59
4. Theobromine 62
5. Albumin 67
6. Starch 70
7. Cellulose or crude fibre 72
8. Sugar and plant acids 73
9. The mineral or ash constituents 73
b) The Cacao Shells 76
Second Part: =The Manufacture of Cacao Preparations=
A. =Manufacture of Chocolate= 85
I. The Preparation of the Cacao Beans 87
1. Storing, cleansing and sorting 87
2. Roasting the Beans 89
3. Crushing, hulling and cleansing 100
4. Mixing different kinds 108
II. Production of the Cacao Mass and Mixing with Sugar 109
5. Fine grinding and trituration 109
6. Mixture with sugar and spices 117
7. Treatment of the Mixture 119
a) Trituration 119
b) Levigation 123
c) Proportions for mixing cacao mass, sugar and
spices 136
III. Further Treatment of the Raw Chocolate 138
8. Manufacture of “Chocolats Fondants” 138
9. Heating Chambers and Closets 141
10. Removal of Air and Division 143
IV. Moulding of the Chocolate 149
11. Transference to the Moulds 149
12. The Shaking Table 156
13. Cooling the Chocolate 162
a) Cooling in Chambers.
b) Cooling in Closets.
V. Special Preparations 176
a) Chocolate Lozenges and Pastilles 176
b) “Pralinés” or coated goods 182
B. =The Manufacture of Cocoa Powder and “Soluble” Cocoa= 195
a) The various methods of disintegrating or opening up the
tissues of cacao 195
b) Methods of disintegration 197
1. Preliminary Treatment of the Beans 197
2. Expression of the Fat 199
3. Pulverising and Sifting the defatted Cacao 209
c) Disintegration after Roasting 216
1. Disintegration ~prior~ to Pressing 217
2. Disintegration ~after~ Pressing 224
3. Opinions to these methods 225
C. =Packing and Storing of the Finished Cacao Preparations= 228
a) General hints 228
b) Suitable storage 228
c) Machines for packing en masse 229
Third Part: =Ingredients used in the Manufacture of Chocolate=
A. =Legal enactments. Condemned ingredients= 230
B. =Ingredients allowed= 231
I. Sweet Stuffs 231
a) Sugar 231
b) Saccharin and other sweetening agents 234
II. Kinds of Starch, Flour 236
1. Potato starch or flour 236
2. Wheat starch 236
3. Dextrin 237
4. Rice starch 237
5. Arrowroot 237
6. Chestnut meal 238
7. Bean meal 238
8. Salep 238
III. Spices 238
a) General Introduction 238
b) Vanilla 241
c) Vanillin 243
d) Cinnamon 246
e) Cloves 247
f) Nutmeg and Mace 247
g) Cardamoms 248
IV. Other Ingredients 248
a) Ether oils 248
b) Peru balsam and Gum benzoin 249
V. Colouring Materials 250
Fourth Part: =Examination and Analysis of Cacao Preparations=
A. =Chemical and microscopial examination of cacao and cacao
preparations= 253
a) Testing 253
b) Chemical analyses 254
1. Estimation of moisture 254
2. Estimation of ash 255
3. Estimation of silicic acid in the ash 256
4. Estimation of alkalis remaining in cocoa powders 256
5. Determination of the fatty contents 258
6. Determination of Theobromine and Caffeine 263
7. Determination of Starch 264
8. Determination of crude Fibre 266
9. Determination of Cacao husk 267
10. Determination of Sugar 269
11. Determination of Albuminates 271
12. Investigation of Milk and Cream Chocolate 272
c) Microscopical-botanical investigation 275
B. =Definitions of Cacao Preparations= 279
a) Regulations of the Association of German Chocolate Manufacturers
relating to the Trade in Cacao Preparations 279
b) Final Wording of the Principles of the Free Union of German
Food Chemists for the estimation of the Value of Cacao
Preparations 282
c) Vienna Regulations 284
d) International Definitions 285
C. =Adulteration of Cacao Wares and their Recognition= 288
a) Introductory 288
b) The Principles 288
c) Laws and Enactments as to Trade in Cacao Preparations 291
1. Belgium 291
2. Roumania 293
3. Switzerland 294
4. Austria 298
5. Germany 301
Fifth Part: =Appendix=
A. =Installation of a Chocolate and Cacao Powder Factory (with
2 plates=) 304
1. Chocolate Factory (Table I) 305
2. Cacao Powder Factory (Table II) 306
3. Appendix containing an account of the methods of preparation
and the composition of some Commercial dietetic and other
cacao preparations 306
INDEX
A. Index to literature 319
B. Tables 320
C. Figures 321
D. Authors 323
E. Alphabetical index to contents 326
+Part I.+
The Cacao Tree.
A. Tree and Beans.
a) Description of the Cacao Tree and its Fruit.
The cacao tree with its clusters of red blossom and golden yellow
fruits is conspicuous even in tropical vegetation. Of considerable
diameter at the base, it often attains a height of eight metres. Its
wood is porous and light; the bark is cinnamon coloured, the simply
alternating leaves are from 30 to 40 cm. in length and from 10 to 12
cm. broad, growing on stalks about 3 cm. long. The upper surface of
these leaves is bright green, and the other one of a duller colour, and
slightly hairy.
The flowers, which are often covered with hairs, occur either singly or
united in bunches not only on the thicker branches but also all along
the trunk from the root upwards. (Fig. 1 A.)
The formation of the fruit takes place only from the flowers of the
stem or thicker branches, and for a thousand flowers there is only one
ripe fruit.
The flowers (fig. 1 B & C) are very small and of a reddish white
colour. Calyx and corolla are five partite, the ten filaments are
united at their base (fig. 1 G) and only half of them are developed to
fruitful organs, such as bear pollen (fig. 1 J) in their four separate
anther compartments (fig. 1 H).
The pistil is formed of five united carpels and bears in each of its
five compartments eight ovules. (Fig. 1 E & F).
The fruit is at first green, and afterwards turns yellow, but with
streaks and tints of red occurring; many varieties also are entirely
crimson. Resembling our cucumber in size, shape and appearance (see
fig. 2 A & B), it has a length of about 25 cm. and a diameter of 10
cm., and the thickness of its shell is from 15 to 20 mm. This shell is
of rather softer consistency than that of the gourd, and has five deep
longitudinal channels, with five others of less depth between them.
[Illustration: Fig. 1. (After Berg & Schmidt, Atlas.)
_A_ Twig in bloom (1/2). _B_ Flower (3/1). _C_ Flower in vertical
section (3/1). _D_ Leaf of flower (6/1) _E_ Bean-pod in vertical
section (6/1) _F_ Bean-pod in cross section (9/1). _H_ Anther. _J_
Pollen.]
The shell encloses a soft, sweetish pulp, within which from twenty-five
to forty almond shaped seeds are ranged in five longitudinal rows,
close to each other. The white colour of these seeds is frequently
tinged with yellow, crimson, or violet (Sec. Fig. 2 C. D. & G).
[Illustration: Fig. 2. (After Berg & Schmidt).
_A_ Fruit with half of shell removed (1/2). _B_ Fruit in cross section
(1/2). _C_ Side view of seed (1/3). _D_ Front view of seed (1/1). _E_
Seedling (1/1). _F_ Kotyledon or Seed-leaf (1/1). _G_ Seed in cross
section (1/1).]
The fruits ripen throughout the whole year, though but slowly during
the dry season; and the time needed for its full development is about
four months. It may be gathered at all times of the year, although
there are regular gathering seasons, determined and modified by the
respective climatic conditions. So, for example, we find that in Brazil
the principal gathering takes place in February and July, whilst in
Mexico it is in March and April. In the primeval Amazonian forests the
fruit of the cacao tree is gathered and brought to market at all times
of the year, wherever Indian tribes obtain.
b) Geographical Distribution and History of the Cacao Tree.
The cacao tree flourishes in a warm, moist climate. It is therefore
indigenous to tropical America, from 23° north to 15° or 20° south
latitude.
Consequently the area in which it grows comprises the Central American
republic of Mexico down to the Isthmus of Panama; Guatemala, the
Greater and Lesser Antilles, Martinique, Trinidad, St. Lucia, Granada,
Cuba, Haiti, Jamaica, Puerto Rico, Guadeloupe, and San Domingo; in
South America, the republics of Venezuela, Columbia, Guiana, Ecuador,
Peru and the northern parts of Brazil, especially the districts lying
along the middle Amazon.
In all other countries where the cacao tree now flourishes, it has been
naturalised, either by colonists, or with government aid, as in Asia,
where the Philippine Islands, Java, Celebes, Amboyna and Ceylon in
particular are deserving of mention; and in Cameroon (Bibundi, Victoria
and Buea), Bourbon, San Thomé and the Canary Islands in Africa, where
the tree is sometimes found growing at an elevation of about 980 ft.
above sea level. Ceylon offers an instructive illustration of the zeal
with which the cultivation is carried on in some districts. According
to information furnished by Mr. Ph. Freudenburg, late German Consul
at Colombo, cacao had been planted in a few instances during the time
Ceylon was in possession of the Dutch, but only since 1819 has seed
been distributed out of the botanical gardens at Kalatura, and it was
still later before planters could obtain it from those established
at Peradenija. Systematic cultivation for commercial purposes was
commenced in 1872 or 1873. The principal seats of cacao plantations are
Dumbara, Kurunegalla, Kegalla and Polgahawella, together with North,
East and West Matala, Urah and Panwila.[1] According to statistical
records, the relation between the growth and export of cacao is shown
by the following table, which also shows the development of its
cultivation:
Year Area under Exports
cultivation (acres) (cwts)
1878 300 10
1879 500 42
1880 3000 121
1881 5460 283
1885 12800 7247
1892 14500 17327
1895 18278 27519
1898 22500 32688
1908 39788 62186
Like all other articles of human food, cacao has a history of some
interest, the most essential points of which are here summarised from
the excellent work of A. Mitscherlich.[2]
A knowledge of the cacao tree was first brought to Europe in 1519 by
Fernando Cortez and his troops. He found in Mexico a very extensive
cultivation of cacao, which had been carried on for several centuries.
In the first letter addressed by Cortez to Charles the Fifth, he
described cacao beans as being used in place of money. Cortez applied
to the cacao tree the name of “Cacap”, a word derived from the old
Mexican designation “Cacava-quahitl”. The Mexicans called the fruit
“Cacavacentli”, the beans “Cacahoatl” and the beverage prepared from
them “Chocolatl”[3], said to be derived from the root “Cacava” and
“Atl”, water. This term was adopted by the Spaniards, and it gave rise
in the course of time to the word “Chocolate”, which is now universal.
The botanical definition of the typical form of the cacao tree, which
belongs to the family BUTTNERIACEAE, is referable to Linnaeus, who gave
it the name “Theobroma Cacao” (food of the gods, from “Theos”, God,
and “Broma”, food). Probably chocolate was a favourite beverage with
Linnaeus, who may have been acquainted with the work of the Paris
physician Buchat, published in 1684, in which chocolate is alluded
to as an invention more worthy of being called food of the gods than
nectar or ambrosia. Clusius first described the cacao tree in his
“Plantae exoticae”. The taste for chocolate soon spread throughout
Spain after the return of Cortez’ expedition from the New World, not,
however, without encountering some opposition, especially on the part
of the clergy, who raised the question whether it were lawful to
partake of chocolate on fast days, as it was known to possess nutritive
properties. However, it found an advocate in Cardinal Brancatio, who
described it as an article belonging, like wine, to the necessaries of
life, and he therefore held that its use in moderation could not be
prohibited. In 1624 Franciscus Rauch published a work at Vienna, in
which he condemned the use of chocolate and suggested that the monks
should be prevented from partaking of it, as a means of preventing
excesses. About the commencement of the 17th century, the use of
chocolate spread from Spain to Italy, where it was brought to the
notice of the public by the Florentine Antonio Carletti (1606), who had
lived for some time in the Antilles. The method of converting cacao
beans into chocolate was also made known in Europe by Carletti, while
the Spaniards had kept it a secret. Under Theresa of Austria, wife of
Louis XIV, the habit of taking chocolate appears to have become very
common in France after the partial introduction of cacao by importation
from Spain. The first cacao imported from the French colony of
Martinique arrived in Brest in 1679 in “Le Triomphant”, the flagship of
admiral d’Estrées. Opinion in France as to chocolate was then divided:
Madame Sévigné, once an admirer of chocolate, afterwards wrote to her
daughter: “il vous flatte pour un temps et puis il vous allume tout
d’un coup fièvre continue qui vous conduit à la mort”, a theory which
nowadays must necessarily be regarded as ridiculous.
Chocolate was in general use in England about the middle of the 17th
century. Chocolate houses, similar to the coffee houses of Germany,
were opened in London. Bontekoë, physician to the Elector Wilhelm of
Brandenburg, published in 1679 a work entitled “Tractat van Kruyd,
Thee, Coffe, Chocolate,” in which he spoke very strongly in favour
of chocolate and contributed very sensibly to the increase of its
consumption in Germany. The first chocolate factory in Germany is said
to have been erected by Prince Wilhelm von der Lippe about the year
1756 at Steinhude. This prince brought over Portuguese specially versed
in the art of chocolate making.
c) Cultivation of the Cacao Tree; Diseases and Parasites.
The first information regarding the cultivation of the cacao tree
in Mexico is that obtained on the invasion of the country by the
Spaniards. Prior to that time there is a total absence of anything
definite. The tree flourishes best in situations where the mean
temperature is between 24° and 28° C. The farther the place of
cultivation from the equator the poorer is the product. The other
most essential conditions are long continued moisture of the soil
and a soft, loose texture with abundance of humus, and above all,
shelter from the direct rays of the sun. For these reasons, planters
select for their cacao areas ground the virgin soil of which has not
been exhausted by the cultivation of other plants. The plants are
either raised in a nursery until they reach the most suitable age
for transplanting, or the seeds are sown on the ground selected for
the plantation. The transport of live seed for new plantations is
attended with some difficulty, since the seeds very quickly lose their
vitality. C. Chalot[4] recommends that this vitality be preserved by
gathering the fruit before it is perfectly ripe, immersing it in melted
paraffin oil, and then wrapping it in paper; on which the fruit may be
transported without losing any of its nutritive qualities.
In the sheltered valleys of tropical countries, where the soft soil,
rich in humus, is kept constantly moist by large rivers, the cacao tree
blossoms throughout the whole year. When growing wild it is generally
isolated under the shadow of larger trees; when cultivated, the young
plant is placed under the shelter of banana trees, and at a later
period of its growth shelter is provided by the coral (called Erythrina
corallodendron or Erythrina indica), further known as “Coffie-mama”
among the Surinam Dutch and madre del cacao among the Spaniards. Yet
this tree, like the Maniok, is said not to enjoy so long a life as the
cacao plant, which sometimes reaches an age of forty years. On this
account the Castilloa or also Caesalpina dashyracis have recently been
recommended as a more lasting protection. The fact that it does not
lose its leaves during the dry season (e. g. on Java, during the East
Monsoon) is an additional advantage.
A cacao plantation requires a considerable area, in the proportion of
50 hectares for 20,000 trees. The quantity of fruit to be obtained
from that number of trees, as an annual crop, would be worth from
£ 1,200-1,300. In planting the seeds, they are set in rows that are
from 8 to 10 m. apart, four or five seeds being planted within from
1 to 2 m, the shading trees being planted between the rows. Of each
five seeds planted the greater number often fail to germinate, either
in consequence of unfavourable weather or as the result of attacks
by insects etc.; but if more than one plant grows, the weaker ones
are pulled up. Until the plants are two or three years old, they are
protected by a shed open at one side, and they are transplanted after
they have attained a height of 3 ft. The chief enemies of tropical
cultivation—weeds, aerial roots, insects, bacterial infection—have to
be provided against continually, so as to prevent damage; accordingly
if the ground be not moist enough, it should be systematically watered,
and so drained if marshy, for the tree requires most careful nursing
if it is to develop into a prolific fruit-bearing specimen. The seed
germinates about fourteen days after being planted; but flowers are not
produced till after 3 or 5 years. After the tree has once born fruit,
which may occur at the end of the fourth year it often continues to
do so for fifty years. The tree is most prolific when from twelve to
thirty years old.
As in the case of all cultivated plants and domestic animals, the
existence of which does not depend on the principal of natural
selection, and among which life is not a continuous development of
endurance in the face of adverse elements, the cacao tree has its
peculiar diseases. Indeed, it would seem as though it were beset by all
vermin extant. The reader may obtain some idea of the extent of the
damage done to cacao plantations by such noxious agents, if he turns up
the clear and exhaustive account published by the Imperial Biological
Institute for Agriculture and Forestry (Germany).[5] Unfortunately we
have not space here to mention more than a few of the most frequently
occurring and important diseases, such as the GUM DISEASE, which is
especially destructive, gum formations in the wood tissue and bark of
the tree eventually killing it. Next to be dreaded are the various
fungus growths, cancers and cancer-like incrustations (“Krulloten”) and
broom formations. It often happens that specii of beetle attack the
tree, causing decay and rot to set in; such e. g. are the wood-borer,
bark bug, and woodbeetle. Other parasites, again, do not destroy the
whole tree, but are equally detrimental, as they also preclude all
prospects of a harvest. Fruit rot and its like, fruit cancer, and
cacao moths, are notorious in this connection. There are also several
larger creatures which betray a preference for the nutritious fruit of
the cacao tree, various species of rat, and the squirrel, which unite
to make the planter’s life a burden.
d) Gathering and Fermentation.
The gathering of the fruit is effected by means of long rods, at
the end of which is a semi-circular knife for cutting through the
stalk. The fruits are then split in two, the beans separated from the
surrounding pulp and spread out on screens to dry, or exposed to the
sun on bamboo floors. Beans so prepared are described as unfermented.
In most lands where cacao is cultivated, another process is adopted,
calculated to heighten the flavour of the fruit and develop its
nutritious constituents. The newly gathered beans are first partially
freed from the fruity substances always adhering, then piled up into
heaps and covered with banana skins or cocoa-nut matting, in order
that they may be shut off as far as possible from all atmospheric
influence, and so left for some time, while the chemical processes of
warming and fermentation are gradually consummating. This procedure
is alternated with repeated exposures to the sun, according to the
maturity and species of the cacao bean, and the prevailing weather
conditions; though details as to the length of time and number of
repetitions necessary to the production of a marketable article
still await determination.[6] It may be taken as a general rule that
fermentation should proceed till the bean, or rather the cotyledon,
has acquired the light brown colour characteristic of chocolate. This
principle is nevertheless often violated, especially as loss of weight
in the bean is often intimately connected with complete fermentation.
Unsufficiently fermented varieties, but which were fully ripe when
gathered, develop a violet colour during this process; it is possible
for them to pass through what is known as “After fermentation” before
reaching the factory. This is not so in the case of beans developing
from unripe fruit, for obviously the valuable constituents of the
cotyledon are here not prominent, and scarcely calculated to ferment
properly. Such can be recognised by their betraying a bluish grey
colour in the drying processes, and the soft and smooth structure which
they then acquire. A normal progress of fermentation is indicated where
the interior of the mass of beans registers, on the first morning after
gathering, a temperature not exceeding 30-33° C, 35-38° on the second
day, and on the third morning a temperature not exceeding 43° C. If the
outer shells are marked, the heating has been too severe. In countries
where the harvest season suffers from the periodical rains, drying over
wooden fires[7] is often resorted to. The value of many specimens is
hereby greatly diminished when the roasting is carelessly managed, for
the smoke must on no account be allowed to come into contact with the
bean. Yet “Smoky” lots among the St. Thomas, Accra, and Kameroon sorts
were formerly much more frequent in commerce than now, for the planter
has learned to avoid this evil. After they have been fermented, the
beans are washed, or trodden with the naked foot, in some countries,
and so cleansed from the pulp remains still adhering. They are then
allowed to dry in the open air, and packed into sacks; contact with
metal or stone is strictly to be avoided, which as good conductors of
heat and rapid cooling agents are most disadvantageous. Instead of
piling the beans up in loose heaps, they may be fermented in “Tanks”
made of wood, and where possible, provided with partitions. According
to Kindt, cedar wood has been proved best for this purpose, because
of its enormous resisting capacity. It used to be thought that in
fermentation ensued a germination of the seed,[8] as in the preparation
of malt; but this idea has been proved erroneous. The contrary is
rather the case, for the process almost kills the seed; and when the
sensitiveness of the latter is taken into consideration, and also
the fact that it only develops under the most favourable conditions,
it must be allowed that the statement contains an obvious truth. Yet
chemical change does take place in the fermentation of the seed; but
as to its precise nature, owing to the lack of scientific research on
the scene of operations, we are still unable to dogmatise. It would
therefore be useless to discuss the manifold theories and speculations
bearing on this point, and waste of time to discuss the various
kinds of fermentation and the chemical processes therein involved.
Yet it may almost be taken for granted, that the fresh-plucked bean
contains a so-called glycoside[9] which decomposes into grape sugar,
into an equally amyloids colour stuff (the so-called cacao-red), and
the nitrogeneous alkaloids Theobromine and Kaffein; a change probably
incidental to the fermentation.[10] The sugar might further split
up into Alcohol and Carbonic Acid Gas, although this is by no means
established.
Whilst we have lost our bearings as far as the chemical aspect of
this process is concerned, we are much more firm in respect to the
biological, thanks to researches which Dr. v. Preyers has conducted on
the spot in Ceylon. Preyer’s[11] experiments leave absolutely no room
for objection, and it can safely be accepted that there are no bacteria
present in fermentation, but a fungus-like growth rich in life, a
kind of yeast by him called Saccharomyces Theobromae, and described
in passing;[12] facts which constitute the gist of his findings. He
further establishes that the presence of bacteria often noticed is
absolutely undesirable, and that better results are obtained when all
life is energetically combated, and especially these bacteria. We
should, then, be confronted with the same phenomenon in the preparation
of cacao as are already met with in beer brewing, and the pressing of
wine and which are still waited for in the preparing of tea and tobacco.
The kernel of the fresh bean, “Nips”, is white and has a bitter taste
and alternates in colour between whitish yellow, rose and violet; the
mere influence of solar heat is sufficient to produce the brown cacao
pigment, but drying is not so effective as fermentation in removing
the harsh bitter taste and hence fermented beans are always to be
preferred. These have often acquired a darker colour in the process,
their weight is considerably diminished, and their flavour modified to
an oily sweetness, without losing an atom of the original aroma[13].
Commercially and for manufacturing purposes only the seeds of the
cacao tree are of importance. The root bark is said by Herr Loyer of
Manila to be of medicinal value as a remedy for certain common female
complaints and is employed by the natives of the Philippine Islands as
an abortifacient. According to Peckoldt[14] the fruit shell contains
a considerable amount of material that yields mucilage and might
therefore be utilised as a substitute for linseed.
e) Description of the Beans.
The varieties of the cacao tree which yield the beans at the present
time occurring in commerce are.
Theobroma cacao, Linné the ~true cacao~, spread over the widest
area, and almost ~exclusively cultivated on plantations~, with
many varieties (Crillo, Forastero etc.) and Theobroma ~bicolor~, a
party-coloured cacao tree the seeds of which are mixed with Brazilian
and Caracas beans.
Theobroma speciosum Wildenow, which yields, like Theobroma cacao,
Brazilian beans (magnificent tree).
Theobroma quayanense, yielding Guiana beans.
Theobroma silvestre or forest cacao.
Theobroma subincanum, ~white-leaved-cacao~, and Theobroma
microcarpum, ~small-fruited cacao~, ~are met with as
admixtures~ in Brazilian beans.
Theobroma glaucum, ~grey cacao~, fruits of which variety are found
among Caracas beans.
Theobroma angustifolium the ~narrow-leaved~ and Theobroma
ovatifolium, ~oval leaf~, may be regarded as characteristic of
Mexican cacao.
Before describing the commercial kinds of cacao, a knowledge of which
is of first importance to manufacturers, it is desirable to consider
the beans in regard to external form and microscopial structure, in
order that the use of some indispensable scientific expressions in the
subsequent description of particular commercial kinds of cacao may be
intelligible.
The bean, page 3 Fig. 2 C-G, consists, according to Hanousek[15], of
a seed-shell, a seed-skin and the embryo or kernel with the radicle.
The oval-shaped seed is generally from 16 to 28 mm. long, 10 to 15
mm. broad and from 4 to 7 mm. thick. At the lower end of the bean
there is a depressed, flattened and frequently circular hilum visible,
from which a moderately marked line extends up to the apex of the
bean where it forms the centre of radiating longitudinal ribs—
vascular bundles-extending to the middle of the bean through the outer
seed-coating back to the hilum.
The outer seed shell (cf. Fig. 3) is of the thickness of paper,
brittle, scaly externally and reddish brown, lined with a colourless
translucent membrane peeling to the so-called silver membrane
(previously but falsely known as seed envelope) and penetrating into
the convolutions of the kernel in irregularly divided folds. The shells
of some of the better sorts of beans, such as Caracas, are frequently
covered with a firmly adherent, dense, reddish-brown powder, consisting
of ferruginous loam originating from the soil on which the beans have
been dried and serving as a protection against the attacks of insects.
But opinions are divided as to, the utility of this process.
The fermented kernel consists of two large cotyledons occupying the
whole bean; it is of fatty lustre, reddish grey or brown colour and
often present a superficial violet tinge; and under gentle pressure
readily breaks up into numerous angular fragments the surfaces of
which are generally bordered by the silver membrane. The fragments can
be easily recognised when laid in water. At the contact of the lobes
there is an angular middle rib and two lateral ribs are connected with
the radicle at the broader end of the bean. The ripe fresh-gathered
cacao-kernel is undoubtedly white and the reddish brown or violet
pigment is formed during the fermenting of the bean. But there is
also a white cacao, though seldom met with. According to information
furnished by Dr. C. Rimper of Ecuador, it is of rare occurrence and is
not cultivated to any great extent. In Trinidad also a perfectly white
seeded cacao, producing large fruit and fine kernels, was introduced
from Central America by the curator of the Botanic Gardens in 1893.
The microscopic structure of the shell, Fig. III., presents no
remarkable peculiarity that requires to be noticed here.
The delicate inner membrane (fig. 3) coating the cotyledons and
penetrating into their folds consists of several layers. Connected
with it are club-shaped glandular structures, fig. 4, consisting of
several dark coloured cells that are known as the ~Mitscherlich
particles~. According to A. F. W. Schimper[16] they are hairs fallen
from the epidermis (fig. 4) of the cotyledon and do not originate, as
was formerly supposed, in the inner silver membrane.
These structures, named after their discoverer, were formerly supposed
to be algae, or cells of the embryo sac, unconnected with the tissues
of the seed cells. They are, however, as true epidermoid structures,
similar to the hairs of other plants.
[Illustration: Fig. 3. Cross Section of Shell of Cacao Bean
(Tschirsch).
_gfb_ vascular bundles
_co_ cotyledon
_pc_ ducts
_f_ pulp
_fe_ endocarp, or inner coat of fruit
_se_ epicarp, or skin
_sch_ mucilagenous, or slime cells
_lp_ parenchyma, or cellular tissue
_st_ sklerogenous, or dry cells
_is_ silver membrane
_co_ cotyledon
_gfb_ vascular bundles]
These Mitscherlich particles are not only ~characteristic of the seed
membrane~, but also of the entire seed as well as the preparations
made from it. Wherever ~cacao is mixed with other materials~,
its presence may be ascertained by microscopical detection of these
structures, which are peculiar to cacao.
In the large elongated, hexagonal cells of the seed membrane there are
two other structures to be seen with the aid of high power (250 fold),
one appearing as large crystalline druses, while the other consists of
extremely fine needles united in bundles.
[Illustration: Fig. 4.
Cross section of the cotyledon, showing “Mitscherlich particles”
(Moeller).]
By addition of petroleum spirit the former, consisting of fat acid
crystals, are dissolved, the latter, remaining unaltered, are
considered by Mitscherlich to be theobromine crystals, since their
crystalline form closely resembles that of theobromine. A more
scientific explanation has not been forthcoming.
The cotyledons are seen under the microscope to consist of a tissue
of thin walled cells, without cavities, lying close together, and
here and there distributed through the tissue, cells with brownish
yellow, reddish brown, or violet coloured contents. These latter are
the pigment cells which contain the substance known as cacao-red and
analogous to tannin; it, together with theobromine, gives rise to
the delicate taste and aroma of cacao. The other cells of the tissue
are filled with extremely small starch granules the size of which
rarely exceeds 0.005 mm.; with them are associated fat, in the form of
spear-shaped crystals, and albuminoid substances.
In order to discriminate between these substances they must be stained
by various reagents. According to Molisch[17], theobromine may be
recognised, in sections of the seed, by adding a drop of hydrochloric
acid and after some time an equal drop of auric chloride solution (3
%) After some of the liquid has evaporated, bunches of long yellow
crystals of theobromine aurochloride make their appearance. On addition
of osmic acid the fat is coloured greyish brown. On addition to the
microscopic section a drop of iodine solution, or better iodozine
chloride, the starch becomes blue, while albuminous substances are
coloured yellow. Cacao starch granules are very small and cannot well
be mistaken for other kinds, except the starch of some spices such
as pimento or that of Guarana, prepared from the seeds of Paulinna
sorbilis. According to Möller the blue iodine colouration of cacao
starch takes place very slowly and it is probably retarded by the large
amount of fat present; but the point has been contested by Zipperer and
later investigators.
In order to make the starch granules of cacao and the cells containing
cacao-red distinctly visible under the microscope, it is advisable
to immerse the section in a drop of almond oil, because the addition
of water renders the object indistinct in consequence of the large
amount of fat present. Another excellent medium for the microscopic
observation of cacao is the solution of 8 parts of chloral hydrate in 5
parts of water, as recommended by Schimper.[18]
By these means it may easily be seen that the pigment or cacao red in
different sorts of cacao varies more or less in colour.
To complete the account of the microscopic characters of the cacao
cotyledon, mention must be made of the small ~vascular bundles~,
generally spiral, that are distributed throughout the tissues of the
cotyledons and are readily made visible by adding a drop of oil or a
drop of chloral hydrate solution.
f) The Commercial Sorts of the Cacao Bean.
Mindful of Goethe’s dictum: ~Friend, the paths of theory are
uncertain, and hid in gloom~, we propose to devote this chapter
to an exclusively practical discussion of the commercial value of raw
cacao, and from the merchant’s point of view.
Such differences of opinion prevail in manufacturing circles as to
the possible uses of each separate sort, that for this reason alone
any other than a purely geographical classification would scarcely be
feasible. But apart from this, varying as it does with the protective
duties imposed, the commercial value of cacao can by no means remain
a universal constant; and it must be noted that variations in the
national taste serve to heighten its instability.
This latter circumstance also causes a deviation from the nearly
related principal that the Motherland becomes chief consumer of the
varieties grown in her colonies. The cacao sorts of the English
Gold-Coast running under the collective name of ~Accra~, have
taken complete possession of the German market; Trinidad cacao enjoys
immense popularity in France, and the Dutch pass on the larger part of
their Java importations to other consuming nations. As regards this
latter sort, however, the fact they are chiefly employed as colouring
and covering stuffs for other cacaos must be taken into consideration.
In most cases either the producing country or a principal shipping
port gives its name to the different sorts. Yet paradoxical exceptions
will at once occur to the reader. The inferior and mediocre Venezuelan
varieties of the Barlovento district shipped from La Guayra are
generally denominated as ~Caracas~, notwithstanding the fact
that the capital of the republic Venezuela, situated as it is 1000
metres above sea level (being about 3300 feet), and therefore quite
outside the cacao zone, has practically no connection with the cacao
trade. The collective name, Samana still holds good for the cacaos
of the Dominican republic, at least in Germany, although this outlet
of a tiny mountainous peninsular has long ceased to export any but
very insignificant quantities. Consequently, and rightly, the French
merchant specifies these sorts as ~Sanchez~, adopting the name
of the principal cacao exporting port of the republic. Arriba, the
choicest product of Ecuador (port, Guayaquil) takes its name from the
Spanish word arriba, above, the plantations being situated along the
upper sources of the Rio Guayas (to wit, the rivers Daule, Vinces, and
Zapotal). Other Guayaquil cacaos are named after the rivers (Balao,
Naranjal) and districts (e. g. Machala) where they are most cultivated.
As in the case of so many other cultivated plants, distinguishing
characteristics of the various sorts are not only determined by the
different species of tree, but are rather and principally dependant on
the combined effect of physical and climatic conditions. So whether
the seedling Criollo, the splendid Creole bean native to Venezuela,
belongs also to the more fruitful Forastero species (spanish forastero,
foreign), a variety less sensitive and consequently commoner, is a
problem which can only claim secondary consideration.
Apart from the geographical influences mentioned, method and nicety
of procedure are of prime importance in the preparation of the cacao
sorts. Yet technically perfect implements do not always prove the
best means to an attainment of this end; it being a fact recorded by
experience that the chemical constituents of the cacao bean reach
their fullest developement in such simple and primitive processes as,
e. g. are still patronised in Ecuador and Venezuela. It is scarcely
necessary to observe that these simple and primitive methods postulate
nicety and carefulness, which failing, there will be no lack of defects
in the cacao prepared. On the Haiti/Domingo island, e. g. a variety
of cacao is harvested which is in itself very profitable, as stray
specimens finding their way to the market testify, but which as an
article of commerce proves most unreliable, being generally brought
on the market in such an unprepared state, that fermentation first
takes place on the sea voyage, and then of course only in insufficient
measure. During this period appear those disagreeable and accompanying
symptoms technically known as “Vice propre” and the beans, which
were not completely ripe in the first place, do not develop further,
and greenish breakings in the skin become pronounced, and remain a
source of terror to the manufacturing world. All attempts made in
European interests to bring about an alteration in this deplorable
state of affairs have hitherto been lost on the indolence of the
native planters. Indeed, until the political and economical conditions
prevalent among the mixed Negro population of Haiti/Domingo are
thoroughly reformed, no perceptible improvement can be expected in
the qualities of the Samana and Haiti cacaos, for which reason, with
rapidly disappearing exceptions, there are scarcely any well organised
plantations in these parts.