permanent shade trees are generally planted about 12 to 14 m apart. It is desirable to plant a large number at first and gradually thin them out. They should have their canopy about 10 to 14 m above the coffee plants. Shade trees require constant attention by pruning and lopping to furnish the required shade.
Shade trees are usually raised from seeds and also from stakes. Seedlings are grown in the nursery for a year before being transplanted in the soil.
HARVESTING AND PROCESSING
Quality is a summative index of many characteristics of coffee, such as its appearance in the raw, roast tastes and its liquor qualities comprising factors like aroma , body and acidity. Quality can be influenced by nutritional factors and weather conditions during the development stages of the beans. Correct processing techniques are essential to prevent deterioration in quality. Coffee is processed in two ways:
(a)wet processing by which plantation or parchment coffee is prepared, and
(b)the dry method by which cherry coffee is prepared.
Parchment coffee prepared by using the wet method is generally favoured by the market. Cherry coffee, due to its very nature of preparation and longer contact with the mucilage and fruit skin, is usually associated with a characteristic fermenting flavour.
Harvesting. For the preparation of both parchment and cherry types of coffee, picking of the right types of fruit forms an essential part of processing. Coffee is picked when the fruits are just ripe. Under and over-ripe fruits cause deterioration in quality, the former gives "immature beans" and the latter "foxy" coffee. They may be dried seperately for making cherry coffee. the bags used are frequently washed and dried. Bags in which fertilisers, pesticides and fungicides are stored should never be used for this purpose.
Preperation of parchment coffee
PULPING. The preperation of coffee with the wet method requires pulping equipment and clean water supply. Fruits are pulped on the same day to avoid fermentation. The pulper should be checked everyday to prevent cuts. The pulper-nipped beans and other deformed beans will result in defective parchment.
Fruits may be fed into the pulper through a sipho arrangement to ensure uniform feeding and to seperate lights and floats from sound fruits. Uniform feeding ensures the proper removal of skins and prevents cuts, choking of the pulper etc. The pulped parchment should be sieved to eliminate any unpulped fruits and skins.
The skins seperated by pulping are led away from the vats into the collection pits, so that their microbial decomposition will not affect the bean quality when they get mixed with the bean.
DEMUCILAGING AND WASHING. The mucilage on the parchment skin can be removed by using any one of the following methods: (a)natural fermentation, (b)treatment with alkali, and (c) frictional removal in machines like 'Raoeng' and 'Aqua pulpa'.
Natural fermentation is the most commonly used method for demucilaging coffee. The mucilage breaks down in the process of fermentation. In the case of arabica, it is complete in 24 to 36 hours. Fermentation takes longer in cool water than in warm weather. If the parchment is under fermented, the sticky mucilage is left on the parchment. This condition leads to the absorption of moisture by the bean and to m[ustiness in the final product. When correctly fermented the mucilage comes off easily and the parchment does not stick to the hand after washing. The beans feel rough and gritty when squeezed by hand.
The robusta coffee has more of sticky mucilage. Fermentation will not be complete even after 72 hours. Quite often the mucilage breakdown is not complete even after a very long period. Thus we resort to alkali treatment or frictional removal of the mucilage.
When the mucilage breakdown is complete clean water is let in and the parchment is washed pebble-clean with 3 to 4 changes of water.
Treatment with alkali. The removal of mucilage by treating with alkali takes about one hour for arabica and one and a half to two hours for robusta. The pulped beans are drained off excess water and furrowed with gorumanes (wooden ladle with long handle). A 10 % solution of caustic soda is evenly applied to the furrows using a rose can. About one kg of sodium hydroxide dissolved in 10 litres of water is sufficient to treat 25 to 30 forlits of wet parchment . The parchment is agitated thoroughly with gorumanes as to make the alkali come into contact with the parchment and is trampled for about half an hour. When the parchment is no longer slimy, and rattles, clean water is let in and the parchment washed clean with 3 or 4 changes of water.
Removal of mucilage by friction. There are pulpers such as 'Raoeng' and 'Aqua Pulpa' which pulp and demucilage the beans in one operation. A number of naked and bruised beans may occur in the parchment. It is thus necessary to adjust the machines to obtain uniform pulping and demucilaging. The sorting of fruits for uniform feeding by a siphon arrangement may also rectify this to a cosiderable extent. these machines are also often used for demucilaging after removing the fruit skins in the traditional pulpers.
UNDERWATER SOAKING. Wherever water supply is abundant and additional vats are available, the parchment is soaked for 12 hours and then given a final wash. This improves the quality both in appearance and in the cup.
DRYING the next stage in processing consists of drying the parchment in the sun until the moisture content is sufficiently reduced to permit the storage of beans till they are despatched to curing works.
When coffee is being dried it is necessary that all naked beans , pulper-nipped and bruised beans are sorted out and despatched to curing works seperately.
The coffee is then bagged into clean new gunnies. The coffee of different lots should be bagged seperately. New gunnies should always be turned inside out and well aerated before use , as otherwise coffee will absorb natural oils and off odours from the bag and give rise to an 'acrid' cup.
