Preparation Of Coffee The For Market
( Originally Published 1900 )
THE cherries as gathered each contain normally two seeds or coffee beans. Each bean is enveloped by the thin delicate silver skin, and outside this by the parchment, and both are enclosed in the fleshy pulp of the outer portion of the fruit. All these coverings have to be removed to prepare the beans for consumption. This may be done in one of two ways, (1) the older or dry method, still practised in Arabia and some other countries, and (2) the modern or wet method, often spoken of as the West Indian process.
THE DRY METHOD OF PREPARATION
The beans are spread out on stone drying grounds, commonly known as barbecues, in a layer a few inches deep. During the first day or two they are frequently stirred so that all are exposed to the sun, and afterwards means are usually adopted so that they can easily be removed under cover at night or at any other time when there is any chance of their being made damp again. The pulpy covering ferments and gradually dries, the whole processes taking two or three weeks. When thoroughly dry the beans can be stored any length of time until wanted, when all that has to be done is to remove the dried pulp in a primitive manner by pounding in a mortar similar to those used in the process of husking rice, or, as is now more usual, in a hulling machine. In either case the dried covering is broken up and the beans set free.
The dry method, although it is simpler and requires less - expensive machinery, is gradually falling into disuse, and even in Brazil, where it is still prevalent, it is losing ground, because the modern wet method is quicker and is independent of the continuance of settled fine weather over a considerable period.
THE WET METHOD OF PREPARATION
In the " wet " method of preparation the cherries as brought in from the field are placed in a large tank full of water. The well-developed cherries are heavy and sink to the bottom, whence they are drawn off through pipes, whilst the immature and bad fruits (which are light) float on the surface, and are treated separately. The ripe cherries are carried directly to machines called' pulpers.
Pulping. Pulpers are of various types, but one of the oldest, and yet most effective, consists essentially of a rough cylinder—more or less like a very large cylindrical nutmeg grater—which is made to revolve facing a curved metal plate. Between the two there is not room enough to allow the cherries to pass. The cherries are reduced to a pulp by the rasping action of the revolving cylinder. The mixture of seeds and pulp is carried away into a vat full of water, where it is mechanically stirred to cause the seeds to separate from the pulp. The heavy. seeds settle to the bottom whilst the lighter pulp is carried away by an overflow of water. The seeds or beans are drawn off and carried in a stream of water to a kind of sieve, and the water is drained away.
Fermentation. The beans are not yet clean, but the parchment " which is still uninjured is covered with a slimy layer which cannot be got rid of in the pulping machine. To remove it the beans are placed in a cistern or vat. Fermentation is set up and allowed to continue from twelve to forty-eight hours or more. When the fermentation has proceeded for a sufficient length of time the beans are removed to another vat and washed.
Washing. This is sometimes effected by running in enough water to cover the beans and trampling on them with bare feet when the adherent tissue becomes loosened. Successive rinsings with water, stirring with rakes or by special machinery result finally in leaving the parchment coverings quite clean.
During the washing process those beans which are not developed sufficiently and are light float on the surface and are collected separately to be sold as " tailings " of inferior quality. When the washing is completed the beans are strained again and removed to the drying place.
Drying. The way in which this operation is carried out depends largely on climatic considerations. With an assurance of continuous sunshine and a dry atmosphere it is sufficient to spread the beans out on a barbecue or drying floor usually made of stone, with a raised edge. By having sliding roofs to the barbecues, or by the provision of portable drying floors on rails, protection against rain and dew is easily secured. Other planters use trays, which can be placed on supports above the level of the ground and readily carried under cover when necessary. Drying coffee in such trays is illustrated in the picture shown at p. 90. When the sun's heat cannot be relied upon, artificial heat has to be resorted to. One method is to have special drying tables, fitted with steam pipes. The beans are spread on these tables or trays, constantly stirred, and rapidly dried by the application of heat which- can be regulated as desirable.
The colour of coffee, which has such great influence on the market price, chiefly depends on the quantity of water which the beans contain. Blue beans contain more moisture than the green, and these again more than yellow ones, while slow drying in a damp atmosphere gives the beans the colour of lead.
The dried beans are now in the state known as parchment coffee." Each bean is still covered by the delicate silver skin and that again by the parchment which is harder and stronger in Liberian than in Arabian coffee. The produce is frequently exported in this state, and, for some time at any rate, its quality appears to improve whilst it is kept in this condition.
Before, however, the beans can be used the parchment and silver skin must be removed, and this may be done on the estate, at the port of shipment, or at the receiving port or elsewhere, according to weather conditions, supply of labour, and other considerations.
Peeling. The removal of the final coverings is known as peeling. Machines of various types are employed, but in all, the essential is to crack the parchment without injuring the bean. The coffee must be thoroughly dry before this is done, as then the parchment is brittle and more easily broken up, for example, by rollers. Winnowing removes the light pieces of parchment and leaves the heavy beans behind. A further simple rubbing and winnowing gets rid of the silver skin, leaving the beans clean and in the condition of ordinary unroasted coffee.
A very large proportion of the crops of several of the Central American states—notably Costa Rica and Guatema'a—is treated here in the various bonded warehouses. Seeing that the shipping of coffee in this state, that is, with the parchment unremoved, must necessarily take up more room and therefore cost more for freight, it is rational to ask why this is done. In many coffee-growing countries the supply of labour is one that is most difficult to meet, and the planter is not only saved from this but from the expense of erecting machinery—which is afterwards expensive to keep in repair. Probably the principal reason, how-ever, is that coffee freshly husked or " cleaned " is of a brighter and therefore better colour than that cleaned in the country of origin, and which has been thus transported to the various consuming markets. Colour, as we shall see later, being a dominating factor in the value, a higher price is mostly obtained for such London-cleaned parcels. The process of cleaning in this country is as follows :—In the first place, each bag is separately tested to see that the parchment has been sufficiently dried, otherwise the husking cannot be done. The coffee is then shot into a hopper covered with a coarse grating to catch sticks or other refuse. It passes down into a long cylindrical machine internally fitted with blunted knives, which break off the parchment and eventually is pressed through an aperture almost closed in by a strong iron shutter, but sufficiently open to allow the coffee to come through. As it passes out of the cleaner, it has to fall through a second hopper fitted with a powerful fan which effectually blows the parchment skin away, leaving only the cleaned coffee to be dealt with in the sizing machines. Even after the sizing machines it is often found that the pea-berry is mixed with the ordinary flat berries, and an ingenious machine has been devised whereby the berries fall on to a slightly sloping and moving canvas, so arranged that the pea-berry shall roll downwards, but the slope is so gradual that the flats will cease rolling and be carried upwards and in this way are almost perfectly divided. After all this care in separating, the coffee having probably passed through three or even four sieves, it is sometimes found necessary to handpick it in order to remove the discoloured berries. This is done by boys or girls working with a foot treadle which keeps a sheet of canvas revolving, on to which the coffee slowly falls and separates, so that all imperfections can be seen and readily removed. The dust and broken parchment which amounts to from 18 to 20 per cent. of the original shipment is practically valueless.
Sizing. To secure uniformity in size, which is desirable when roasting, the beans are sorted into large, medium and small by passing them through sieves with meshes of certain sizes. The last stage is to pick them over carefully by hand to remove all foreign bodies, broken or discoloured beans, and anything in fact which would lower the value of the product.
The sizing of coffee is, however, by no means universal. For instance, Mocha is not so treated, nor many of those kinds, generally lower grades, which are prepared in what has been described as the dry method, on the estates- where they are grown. Moreover, there is no actual standard for sizing. British-grown -coffee carries the system out to the greatest extent, but even then there is no uniformity ; that marked A or 1 on one estate being no larger than that marked B or 2 on another, in fact it would be wise to discontinue the lettering on the bags, though not to discontinue the sizing.
Transportation. Probably no article of commerce is conveyed to the port of shipment from the plantation in a greater variety of ways owing to the fact that it is grown in such diverse countries and, from its necessitating a high altitude, often in inaccessible -)arts. In Central Africa human porters are employed ; in Arabia camels; in Guatemala, in Costa Rica, and some other Central American states where railroads have not been built, ox-carts ; while in other countries, where obtainable, mules or ponies are requisitioned. Owing to the magnificent inland water navigation which the rivers of Brazil and Colombia provide the transportation to the seaports is considerably easier than in less favoured countries. In all parts, however, the opening up of new railways is solving the transport difficulties and cheapening the cost of production. Further the opening up of new steamship routes, as well as the railways, is the means of accelerating the delivery at the principal consuming markets, so that the various new crops are obtainable some months earlier than used to be the case. In former days, when sailing vessels were chartered to bring a full cargo of coffee, beyond a portion possibly becoming sea-damaged, it mostly arrived in excellent condition ; but with the present system of shipping in large steamers, with many other kinds of merchandise it often happens that the coffee becomes impregnated with objectionable scents and flavours, causing a deterioration of many shillings, and possibly pounds, per ton in value. At times this evil is so pronounced that a parcel, which from its appearance should command a very high price, can only be sold as the lowest grade.
After the beans come on the market they only require roasting and grinding to be ready for use.