The fruit contains within a pericarp a pulp slightly viscous and sweet, within which, covered by a membrane, are the two hemispherical coffee beans placed face to face and each covered by a tender pellicle. It is not unusual to find a single bean in the fruit, which then takes the shape of an ellipsoid grooved in its longer axis—and this is called moka owing to the resemblance which it bears to the coffee of that name.
The coffee chiefly cultivated in Brazil is the Arabica L. and to a small extent also the Liberica Hiern, but other varieties have developed from those, and there are crosses of local kinds such as the Maragogype, which takes its name from the place where it was discovered (Bahia Province). Those varieties are locally known as Creoulo, Bourbon, Java, Botucatú (or yellow bean coffee), the Maragogype, and the Goyaz. The Creoulo, the Botucatú and the Maragogype are wilder and show more resistance than the Java and Bourbon sorts, which are nevertheless more productive under good conditions and with careful cultivation, which the first three qualities do not exact.
The coffee tree is a most serviceable plant, every part of which can be used. Its wood is much used in cabinet making, and makes excellent fuel; its leaves, properly torrefied, and then stewed in boiling water, give a palatable kind of tea; from the sweet pulp of its fruit an agreeable liqueur can be distilled; from its beans can be made the beverage we all know, and from the shells and residue of the fruit a good fertilizer can be produced.
The chemical examination of the cinders of the coffee bean shows that it contains 65·25 per cent of potash, 12·53 per cent of phosphoric acid, 11·00 per cent of magnesia, 6·12 per cent of lime, and some traces of sulphuric and salicylic acid, oxide of iron and chlorine.
An interesting study has been made by Dr. Dafert of the weight of the various components of the coffee tree at different ages, from which it appears that the proportion of potash increases progressively in the organs as they are more and more distant from the roots. The contrary is the case with lime and phosphoric acid, which preponderate generally in the seeds.
With this knowledge a scientific cultivator can judge exactly how to treat the exigencies of the different trees at different ages. Naturally, the condition of the soil has to be taken into consideration in any case. According to experiments made by Dr. Dafert each kilo of coffee beans has extracted from the soil—potash 0·7880 gramme; phosphoric acid 0·4020 gramme; magnesia 0·3240 gramme; lime 0·1470 gramme.
These experiments apply merely to coffee grown in Brazil, and are no doubt at variance with experiments on coffee grown elsewhere. Taking all things into consideration, it has been proved by chemical analysis that the Brazilian coffee comes as near as any in its components to what the normal or perfect coffee should be.
The soil, the elevation of the land, the zone and the climate naturally have considerable influence on the quality of the coffee. The Coffea Arabica seems to feel happy enough in a temperate zone and at elevations from 1,500 to 2,300 ft. The States of São Paulo, Minas Geraes, Rio de Janeiro and Espirito Santo fulfil most if not all these conditions.
Dr. Passos.