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Coffea arabica L.

Rubiaceae
Arabica coffee, Arabian coffee, Abyssinian coffee, Brazilian coffee

Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.

  1. Uses
  2. Folk Medicine
  3. Chemistry
  4. Toxicity
  5. Description
  6. Germplasm
  7. Distribution
  8. Ecology
  9. Cultivation
  10. Harvesting
  11. Yields and Economics
  12. Energy
  13. Biotic Factors
  14. References

Uses

Dried seeds "beans" are roasted, ground, and brewed to make one of the two most important beverages in the western world. In its native Ethiopia, used as a masticatory since ancient times, it is also cooked in butter to make rich flat cakes. In Arabia a fermented drink from the pulp is consumed. Coffee is widely used as a flavoring, as in ice cream, pastries, candies, and liqueurs. Source of caffeine, dried ripe seeds are used as a stimulant, nervine, and diuretic, acting on central nervous system, kidneys, heart, and muscles. Indonesians and Malaysians prepare an infusion from dried leaves. Coffee pulp and parchment used as manures and mulches, and is occasionally fed to cattle in India. Coffelite, a type of plastic, made from coffee beans. Wood is hard, dense, durable, takes a good polish, and is suitable for tables, chairs, and turnery. Coffee with iodine is used as a deodorant (List and Horhammer, 1969-1979). Caffeine has been described as a natural herbicide, selectively inhibiting germination of seeds of Amaranthus spinosus (Rizvi et al, 1980). Caffeine is a widespread additive in over-the-counter diet pills, pain killers, and stimulants (Duke, 1984b).

Folk Medicine

Reported to be analgesic, anaphrodisiac, anorexic, antidotal, cardiotonic, CNS-stimulant, counterirritant, diuretic, hypnotic, lactagogue, nervine, stimulant, coffee is a folk remedy for asthma, atropine-poisoning, fever, flu, headache, jaundice, malaria, migraine, narcosis, nephrosis, opium-poisoning, sores, and vertigo (Duke and Wain, 1981; List and Horhammer, 1969-1979).

Chemistry

Rager's Handbuch (List and Horhammer, 1969-1979) devotes pages of fine print to the chemicals reported from coffee, but perhaps the more hazardous ones are acetaldehyde, adenine, caffeine, chlorogenic acid, guaiacol, tannic acid, theobromine, ard trigonelline. Tyler (1982) produces a chart comparing various caffeine sources to which I have added rounded figures from Palotti (Industric Alimentaire 16:) (1977).

Cup (6 oz.) expresso coffee 310 mg
Cup (6 oz.) boiled coffee 100 mg
Cup (6 oz.) instant coffee 65 mg
Cup (6 oz.) tea 10-50 mg
Cup (6 oz.) cocoa 13 mg
Can (6 oz.) cola 25 mg
Can (6 oz.) coca cola 20 mg
Cup (6 oz.) mate 25-50 mg
Can (6 oz.) pepsi cola 10 mg
Tablet Caffeine 100-200 mg
Tablet(800 mg) Zoom (Paullinia upana) 60 mg
In humans, caffeine, 1,3,7-trimethylxanthine, is demethylated into three primary metabolites: theophylline, theobromine, and paraxanthine. Since the early part of the 20th century, theophylline has been used in therapeutics for bronchodilation, for acute ventricular failure, and for long-term control of bronchial asthma. At 100 mg/kg theophylline is fetotoxic to rats, but no teratogenic abnormalities were noted. In therapeutics, theobromine has been used as a diuretic, as a cardiac stimulant, and for dilation of arteries. But at 100 mg, theobromine is fetotoxic and teratogen (Collins, FDA By-lines No. 2, April 1981). Leung (1980) reports a fatal dose in man at 10,000 mg, with 1,000 mg or more capable of inducing headache, nausea, insomnia, restlessness, excitement, mild delirium, muscle tremor, tachycardia, and extrasystoles. Leung also adds "caffeine has been reported to have many other activities including mutagenic, teratogenic, and carcinogenic activities; ... to cause temporary increase in intraocular pressure, to have calming effects on hyperkinetic children...to cause chronic recurring headache... Coffee drinking has also been linked to myocardial infarction... cancer of the lower urinary tract (e.g. bladder), ovaries, prostrate, and others." Most of these reports have been challenged (Leung, 1980). According to Tiscornia et al (Rev. Ital. Sostanze Grasse 56(8): 283. 1979) the sterol fraction of coffee seed oil contains 45.4-56.6% sitosterol, 19.6-24.5% stigmasterol, 14.8-18.7% campesterol, 1.9-14.6% 5-avenasterol, 0.6-6.6% 7-stigmasterol, and traces of cholesterol and 7-avenasterol. Coffee pulp is a valuable cattle feed, unpalatable to cattle at first. The pulp is comparable to corn in total protein, and superior to it in calcium and phosphorus content. In India, cattle feed on the pulp with no apparent ill effects. The ash of "cherry" husk is rich in potash and therefore forms a valuable manure. Air dry coffee pulp contains 1.34% N, 0.11% phosphoric acid (P2O5) and 1.5% potash (K2O). After composting these values change to 0.91% N, 0.31% P2O5, 0.71% K2O (C.S.I.R., 1948-1976). Leaves and reject seed may also be used as compost. Leaves are reported to contain, per 100 g, 300 calories, 6.4% water, 9.3% protein, 5.5 g fat, 66.6 g total carbohydrate, 17.5 g fiber, 12.2 g ash, 1910 mg Ca, 170 mg P, 96.6 mg Fe, 2360 ug carotene equivalent, 0.00 mg thiamine, 0.21 mg riboflavin, and 5.2 mg niacin. Seeds contain per 100 g, 203 calories, 6.3% water, 11.7 g protein, 10.8 g fat, 68.2 g total carbohydrate, 22.9 g fiber, 3.0 g ash, 120 mg Ca, 178 mg P, 2.9 mg Fe, 20 4 beta-carotene equivalent, 0.22 mg thiamine, 0.6 mg riboflavin, and 1.3 mg niacin (Duke, 1981b). Raw coffee contains ca 10% oil and wax extractable with petroleum ether. The fatty acids consist chiefly of linoleic, oleic, and palmitic acids, together with smaller amounts of myristic, stearic, and arachidic acids. From the unsaponifiable matter, a phytosterol, sitosterol, cafesterol, caffeol, and tocopherol have been isolated. Among the identified components of the volatile oil present in roasted coffee are: acetaldehyde, furan, furfuraldehyde, furfuryl alcohol, pyridine, hydrogen sulphide, diacetyl, methyl mercaptan, furfuryl mercaptan, dimethyl sulphide, acetylpropionyl, acetic acid, guaiacol, vinyl guaiacol, pyrazine, n-methylpyrrole, and methyl carbinol. All these substances do not preexist in the unroasted coffee beans; some are undoubtedly the products of the roasting process and others are produced by the decomposition of the more complex precursors (C.S.I.R., 1948-1976).

Toxicity

As a long term drinker of 5-10 cups of coffee a day, I do not think I do myself any favors by drinking the coffee. Still I will quote some of the alarming things I have read. Tyler (1982) cites "some evidence linking coffee and cancer of the pancreas." "...Caffeine...in large amounts produces many undesirable side effects--from nervousness and insomnia to rapid and irregular heartbeats, elevated blood sugar and cholesterol levels, excess stomach acid, and heartburn. It is definitely a teratogen in rats" (Tyler, 1982). Michael Jacobson cites numerous studies on pregnant animals and humans in which the equivalent of 3-4 daily cups of coffee caused birth defects such as cleft palate and missing bones (Washington Star, December 20, 1978). I am seeking from MMWR documentation for a rumor I heard that several people were killed in one year by colonic irrigation with coffee, more than were killed by all other herbs combined that year (excluding alcohol, cocaine, heroine, marijuana, and tobacco). In some individuals, caffeine causes nervousness, restlessness, excitement and insomnia. Patients with peptic ulcers, hypertension, and other cardiovascular and nervous disorders are usually advised by their physicians to refrain from drinking coffee. Chlorogenic acid may induce rhinitis and dermatitis in workers engaged, in roasting, sorting, or grinding coffee (Morton, 1977). Mitchell and Rook (1979) note that the role of chlorogenic acid in the respiratory symptoms were discounted. Still workers develop asthma, dermatitis, rhinitis, and urticaria. Inhalation of coffee bean dust can produce coffee worker's lung, a type of allergic alveolitis. Coffee extracts are GRAS ([[section]]182.20), but the GRAS status of caffeine ([[section]]182.1180) is being reassessed (Duke, 1984b).

Description

Evergreen, glabrous shrub or small tree, up to 5 m tall when unpruned; leaves opposite, dark green, glossy, elliptical, acuminate-tipped, short-petioled, 5-20 cm long, 1.5-7.5 cm broad, usually 10-15 cm long and 6 cm broad; flowers white, fragrant, in axillary clusters, opening simultaneously 8-12 days after wetting; corolla tubular, 1 cm long, 5-lobed; calyx small, cup-shaped; fruit a drupe, about 1.5 cm long, oval-elliptic, green when immature, ripening yellow and then crimson, black upon drying, 7-9 months to maturity; seeds usually 2, ellipsoidal, 8.5-12.5 mm long, inner surface deeply grooved, consisting mainly of green corneous endosperm and small embryo; polyembryony recorded. 2,500 dried seed/kg. (Reed, 1976).

Germplasm

Reported from the African Center of Diversity, Arabica coffee, or cvs thereof, is reported to tolerate disease, high pH, insects, laterite, low pH, Photoperiods, shade, slope, and virus (Duke, 1978). Many varieties and cultivars are recorded with 'Typical', 'Bourbon', 'Mundo Novo', and 'Caturra', most popular in Brazil. C. arabica is only natural tetraploid and completely self-fertile coffee. Over 30 mutants are recognized. Disease resistance and cold-resistance bred into some cultivars. 'Kona', grown in Hawaii, with mild flavor; 'Harrar', Ethiopian type; 'Caracolla' or 'Pea Berries 'are seeds or beans derived from one instead of two-seeded berries, usually developed at tips of branches. Crosses between two diploid species, C. eugenioides S.Moore and C. liberica Bull, have produced a hybrid with foliage similar to that of C. arabica (Reed, 1976). Some cvs are short day,others indeterminate. (x = 11, 2n = 44)

Distribution

Despite its name, C. arabica originated in Ethiopia, where it grows at elevations between 1,375 to 1,830 m. It is believed to have been introduced into Arabia prior to the 15th century. It was first planted in Java in 1690, and in the early 18th century was carried to Surinam, Martinique, and Jamaica. Cultivation soon spread throughout the West Indies and Central America and favorable regions of South America. Later, it reached India and Sri Lanka. Today, nearly 90% of the world's coffee comes from this species (Morton, 1977).

Ecology

Ranging from Warm Temperate Dry to Rain (with little or no frost) through Tropical Very Dry to Wet Forest Life Zones, coffee is reported to tolerate annual precipitation of 4.8 to 42.9 dm (mean of 109 cases = 15.8), annual temperature of 16.0 to 28.5°C (mean of 108 cases = 24.8), and pH of 4.3 to 8.4 (mean of 45 cases = 6.4) (Duke, 1978, 1979). Arabica coffee thrives from the humid tropics to temperate climates from 5°N lat. to 34°S lat. where temperatures average 11-26.5°C, and from sealevel to 2,500 m altitude. Rainfall needs to be regular, abundant, and well-distributed, from 800-2,500 mm. Ideal conditions at the equator are 1500-1800 mm. A short, relatively dry season may facilitate flowering and/or pollination. Native Ethiopian soils are deep red to brown-red lateritic loams or clay loams of volcanic origin of high to medium fertility with pH 5.3-6.6. In Brazil, similar soils are used plus red-yellow podzolic types with pH 5-7. Optimal pH has been suggested as 4.5-7.0.

Cultivation

Propagation is usually by seed; however, budding, grafting, and cuttings have been used. Traditional method of plants on virgin soil is to put 20 seeds In each hole 3.5 x 3.5m at the beginning of rainy season. Half are eliminated naturally. In Brazil, a more successful method is to raise seedlings in shaded nurseries. At 6-12 months, seedlings are taken to fields, hardened, and then planted on contoured fields 2-3 m apart in 3-5 m rows. Holes are prepared 40 x 40 x 40 cm and 4 seedlings placed in each. Plants may be shaded by taller trees or left undshaded. Coffee is often intercropped with food crops, such as corn, beans, or rice, during the first few years. Clean weed control is necessary throughout the entire season. Pruning is common practice in some districts. Mulches and green manure are commonly used with chemical fertilizers coming more and more into use. Typical application consists of 175 g N per bush, 100 g P, and 175 g K. P and K added in two applicationa and N added over a longer period with 4-5 applications. Other elements added as soils require them. Shading tends to favor leaf and shoot growth at the expense of root growth. It may be useful when plants are young, but later shading may reduce yields, especially when the trees are fertilized.

Harvesting

Average economic age of plants 30-40 years, with some 100 year old plantations still bearing. Trees come into bearing 3-4 years after planting and are in full bearing at 6-8 years. Fruits mature 7-9 months after flowering. Selective picking of ripe red fruits produces highest quality. Crop ripens over a period of several weeks. In Brazil all berries are stripped at one time onto ground cloths, usually in April to June; in Ethiopia, harvest season is October to December after the rainy season. Berries are dried in sun; in some humid areas, artificial heat is used. Depulping after picking is increasingly practiced. (Reed, 1976)

Yields and Economics

Wild Ethiopian stands yield 200-300 kg/ha/year of clean coffee, with 1 MT/ha as a maximum. Cost of production is 20 30 cents/kg. Brazilian average yield is 400 kg/ha with record yield of 6,600 kg/ha. Cost of production 14-55 cents/kg. In 1979, the world low production yield figure was 120 kg/ha in Sao Tome, the international production was 521 kg/ha, and the world high production yield was 1,736 in Sri Lanka. Leaf-fall from coffee fincas should be 1-2 times production, prunings 1-2 times production, culls 1/4 times production, pulp 1/2 times production, seed coat 1/10 times production. Arabica coffee makes up 90% of the world's coffee; world production being about 70.7 million bags of 60 kg each. Largest producers in order are: Brazil, Colombia, Ivory Coast, Mexico, Angola, Uganda, Indonesia, El Salvador, Ethiopia, and Guatemala. After importing a record 6.1 million pounds of caffeine in 1981, US suppliers report that demand trailed off considerably during the first quarter of 1982. Synthetic caffeine imports averaged 330,000 pounds per month in 1982, cf 513,205 in 1981. Primarily as the result of novel dietary formulations which combine caffeine with phenylpropanolamine, some observers estimate that pharmaceutical applications accounted for perhaps 40% of all caffeine consumption in 1980, compared to the usual 25-30% (CMR, 1982).

Energy

Coffee production usually generates at least four kinds of residue (1) prunings, (2) culls, (3) pulp, and (4) seed coat. Until I can find a published figure, I estimate that trees could be pruned by 1-5 MT/ha/yr, (depending on life zone, age, shading and disease) following harvest with no great loss in production. Purseglove (1968-72) describes five methods of pruning. Plants are topped to check upward growth and encourage secondary branch formation. Pruning should remove all shoots which have borne flowers or fruit, dead and diseased branches, as well as tangled branches. In India, crop bearing tends to be biennial - a heavy crop alternating with a light crop. Regular drastic pruning every year acts as a check on the biennial habit leading towards more systematic but moderate yields. According to an NAS (1977b), dried red coffee bean peels have energy potential of 3,500 calories per kg, compared to 10,000 for fuel oil, 11,000 for natural gas. Coffee hulls contain 3,885, and dry robusta coffee contains3,915 calories. Burkill (1966) reports that 1 MT fruit pulp should yield 127 liters alcohol. The cost of a utilization process can be relatively low, such as the use of waste products--coffee grounds or refuse, sawdust, bagasse, or peanut shells--as fuels by the firms producing them. These wastes can be burned directly or converted to ethanol, reethanol or methane. If legume shade trees are interplanted with the coffee, we expect more firewood from the intercrop and less from the coffee. The energy contributions from intercropped legume's nitrogen fixation are not always insignificant. Young coffee can be intercropped with beans, peanuts or cowpeas for the first two or three years to advantage. Purseglove reported yields of over ca 2,000 Kg/ha clean coffee in Hawaii, with averages of ca 360 in Brazil, 450 in Colombia, 720 in El Salvador, 850 in Costa Rica, and 896 in Kenya. According to Purseglove, defective beans are sometimes picked out by hand. These culls or rejects, may or may not show up in production figures, remaining at the farm or processing plants. I would estimate culls at 5-25% of harvest. Culls could be fermented for alcohol production. In Panama, I was told by Sitton Coffee Company that the pulp constituted 50% of the green fruit, the seed coat (burned with diesel) 5% of the dry seed. In Puerto Rico, it is estimated that an acre producing 1,500 lbs. of market coffee per acre will provide about 2 1/2 tons of pulp yearly (USDA Production Research Report No. 32, 1959).

Biotic Factors

Raw and Free (1977) found that bushes caged with bees yielded 52% more berry than bushes caged without bees. Yields from non-caged bushes were intermediate. These effects were more marked on bushes in full sun. Of the numerous insects captured from the flowers of non-caged bushes, honeybees were more abundant. Many fungi attact Arabica coffee plants, among them the following: Aithaloderma longisetum, Armillaria mellea, Ascochyta tarda, Botrytis cinerea, Botryodiploidia theobromae, Capnodium brasiliense, Cephaleuros mycoidea, C. virescens, Ceratocystis fimbriata, Cercospora coffeicola, Colletotrichum coffeanum, C. dematium, C. coffaephilum, Corticium salmonicolor, C. solani, Curvularia prasadii, Cyphella heveae, Fomes lamonensis, F. lignosus, Fusarium bulbigenum, F. coffeicola, F. decemcellulare, F. diversisporum, F. equiseti, F. graminearum, F. lateritium, F. moniliforme, F. oxysporum, F. semitectum, F. solani, F. sporotrichioides, F. stilboides, F. tumidum, Gloeosporium coffeanum, F. coffeicola, Glomerella cingulata, G. coffeicola, Hemileia vastatrix, Hymenochaete noxia, Irenina isertiae, Leptosphaeria coffeicola, L. coffeigena, Macrophomina phaseoli, Meliola coffeae, M. psychotriae, Mycena citricolor, Mycosphaerella coffeae, M. coffeicola, Myrothecium advena, Nectira tropica, Nematospora coryli, N. gossypii, Phyllosticta coffeae-arabica, Ph. coffeicola, Physarum cinereum, Polyporus coffeae, P. occidentalis, Rhizoctonia bataticola, R. lamellifera, R. solani, Rosellinia bunodes, Rostrella coffea, Sarsopodium coffearum, Sclerotium rolfsii, Scolecopeltis longispora, Septoria coffea, S. berkeleyi, Stilbella flavida, Tripospermum gardneri, Xylaria rhizocala. Pseudomonas garcae is a bacterial disease, and stem pitting is caused by a virus. Cuscuta and Loranthus spp. parasitize trees in some areas. Witches' broom also occurs. Many nematodes have been found with Arabica coffee trees, including the following: Achromadora longiseta, Aphelenchoides parietinus, Aphelenchus coffeae, Cephalobus persegnis, Criconemella curvata, Cryptonchus abnormis, Ditylenchus procerus, Dorylaimus subulatus, Eucephalobus filiformis, E. longatus, Helicotylenchus concavus, H. erythrinae, Ironus ignavus, Meliodogyne africana, M. coffeicola, M. exigua, M. incognita, Monochus gymnolaimus, Paratylenchus besoekianus, Pratylenchus brachyurus, P. coffeae, P. pratensis, Radopholus similes, Rotylenchulus sp., Tricephalobus longicaudatus, Trichodorus sp., Tylenchus acutocaudatus, T. caudatus, Xiphinema basilgoodeyi, X. brevicolla, X. insignis, X. radicidola (Golden, p.c., 1984). Many insects attack coffee plants at various stages and on various structures. Local agricultural agents should be consulted.

References

Complete list of references for Duke, Handbook of Energy Crops
last update July 8, 1996