英文科學讀本 第五冊·Lesson 18 Cocoa

Lesson 18 Cocoa

A cup of hot cocoa forms a very pleasant beverage, and is esteemed by most people as a luxury. It differs from both tea and coffee in that it contains, in addition to its other properties, a considerable amount of flesh-forming matter. It is really food as well as drink, and is therefore a most valuable beverage.

If, again, we compare the three drinks—tea, coffee, and cocoa—we shall find that while the two former are simple infusions, the latter is rather a sort of soup or gruel than an infusion.

We are now going to inquire into the nature and source of this third beverage-making material. But before inquiring what it is, it will be well to say what it is not. Cocoa is not made from the coconuts which we see in the fruiterers' shops. It has no connection with them or with the palm-trees on which they grew. Its real name is cacao, and it is the produce, not of a palm, but of a tree very much like the common cherry-tree. This tree is a native of America. It was found growing there by the first European discoverers of the continent, four hundred years ago. The Indians called it cacao, and they used it, as we do now, for the preparation of a refreshing beverage.

It is now grown extensively in the West Indies, and in Central and South America, and has lately been introduced into some of the tropical countries of Asia and Africa.

The cacao-tree, in its natural or wild state in the forests of Demerara, grows to the height of 30 feet, but under cultivation the pruning-knife keeps it down to the size and shape of an ordinary cherry-tree. It is an evergreen, the leaves being very similar to those of the cherry, except that they are smooth and glossy, as is the general case with evergreens. The tree does not begin to bear till its sixth year, but after that it is very prolific. The flowers, which are small, grow in thick clusters on the trunk and main branches. The fruit is a kind of oblong pod, from 7 to 9 inches in length, and about 4 inches in breadth. It is covered with a thick, outer rind, which takes various colors—yellow, red, purple—as it ripens.

The tree presents an unusual and interesting appearance, as it bears at the same time its abundance of bright, glossy, green leaves; buds in all stages of growth; thick clusters of flowers; and above all, fruit-pods, some yellow, some red, and some purple.

The pod is a hard, tough, woody case, smooth on the outside, oblong in form, and somewhat pointed towards the end. It is divided lengthwise into five compartments or cells, which spring from a central core. Such a pod we call a capsule. In each cell or compartment a number of seeds or nuts are packed closely together round the central core, and embedded in a pinkish-white pulp. Each pod usually contains from twenty to forty of these nuts. They are known as cocoa-beans; it is from them that all preparations of cocoa are made.

The first process in preparing the newly-gathered nuts for the market is to induce them to ferment. This is usually done by burying a heap of them in the damp earth for two or three days, and then spreading them out in the sun. When this fermenting process has advanced far enough, the beans are roasted in revolving metal cylinders, just as coffee is roasted. The roasted beans are next crushed, and broken up into small pieces, commonly known as cocoa-nibs.

Some people prefer to use the cocoa-nibs themselves in the preparation of the beverage. They make excellent cocoa, but they require long and careful boiling. They give out, during the boiling, a very large amount of oil, which may be seen floating on the surface of the liquid when it is cooked. Cocoa is more frequently used in the form of thin, flaky slices, or as a powder. The former is known as flaked cocoa, the latter as soluble cocoa.

Flaked cocoa is prepared by grinding the nibs to a very fine powder, mixing the powder with water into a paste, and rolling the paste into thin sheets, which are then allowed to dry and harden.

In the preparation of soluble cocoa, which is the commonest form in which the article is used, the beans are first pressed, to extract all the oil, and then ground into a powder with a certain quantity of starch. This kind of cocoa thickens when boiling water is poured on it. It is really the starch and not the cocoa that thickens.

Chocolate is the highest form in which cocoa is prepared. The nuts for this purpose are treated as if for ordinary soluble cocoa, except that they are mixed with a certain quantity of sugar and starch, and the whole is then ground into a soft, smooth paste on hot metal tables. In this form, with, generally speaking, a little flavoring matter added, it is moulded into sticks, cakes, balls, etc., which are sold at the confectioners' shops, under the name of chocolate creams.

The name chocolate is our form of the Mexican word chocolatl, the name by which the prepared cacao-bean was known to the natives of Mexico before Europeans visited them.