For growing Arabica coffee beans, there are two optimal growing climates:
The subtropical regions, at high altitudes of 16-24° (Illy, 21). Rainy and dry seasons must be well defined, and altitude must be between 1800-3600 feet. These conditions result in one coffee growing season and one maturation season, usually in the coldest part of autumn. Mexico, Jamaica, the S. Paulo and Minas Gerais regions in Brazil, and Zimbabwe are examples of areas with these climate conditions (Illy, 21).
The equatorial regions at latitudes lower than 10° and altitudes of 3600-6300 feet (Illy, 21). Frequent rainfall causes almost continuous flowering, which results in two coffee harvesting seasons. The period of highest rainfall determines the main harvesting period, while the period of least rainfall determines the second harvest season. Because rainfall is too frequent for patio drying to occur, artificial drying with mechanical dryers is performed in this type of coffee growing environment. Examples of countries that have this climate are Kenya, Colombia, and Ethiopia (Illy, 21).
Robusta coffee is grown at much lower altitudes (sea level-3000 feet) in an area 10° North and South of the equator (Illy, 22). It is much more tolerant to warm conditions than Arabica coffee.
Arabica Coffee Bean Varietals
Coffea Arabica Coffee Beans
Although many varietals of Coffea Arabica exist, C. arabica varietal Arabica (includes var. typica) and C. arabica var. bourbon (named from the island of Bourbon where it was first cultivated) are considered to be the first coffee varietals. Other varietals are believed to be a product of these two cultivars.
Production and resistance generally governs the types of coffee beans that a farm will choose to plant. Coffee quality is a secondary factor most of the time.
Coffee Bean Types
Typica - This is the base from which many coffee varietals have been developed. Like the other Coffea Arabica varietals that have been developed from it, Typica coffee plants have a conical shape with a main vertical trunk and secondary verticals that grow at a slight slant. Typica is a tall plant reaching 3.5-4 m in height. The lateral branches form 50-70° angles with the vertical stem. Typica coffee has a very low production, but has an excellent cup quality.
Bourbon - Bourbon coffee plants produce 20-30% more coffee than Typica, but have a smaller harvest than less most coffee varietals. Bourbon has less of a conical shape than Typica coffee plants, but has more secondary branches. The angles between the secondary branches and the main stem are smaller, and the branch points on the main stem are closely spaced. The leaves are broad and wavy on the edges. The fruit is relatively small and dense. The cherries mature quickly and are at a risk of falling off during high winds or rains. The best results for Bourbon coffee are realized between 3,500-6,500 feet. Cup quality is excellent and similar to Typica.
Caturra - Caturra is a mutation of Coffee Bourbon discovered in Brazil. It is a mutation with high production and good quality, but requires extensive care and fertilization. It is short with a thick core and has many secondary branches. It has large leaves with wavy borders similar to Coffee Bourbon. It adapts well to almost any environment, but does best between 1,500-5,500 feet with annual precipitation between 2,500-3,500 mm. At higher altitudes quality increases, but production decreases.
Catuai - Catuai is a high yielding coffee plant resulting from a cross between Mundo Novo and Caturra. The plant is relatively short, and the lateral branches form close angles with the primary branches. The fruit does not fall off the branch easily, which is favorable with areas with strong winds or rain. Catuai also needs sufficient fertilization and care.
Pache comum - Pache comum is a mutation of Typica coffee first observed on the farm El Brito, Santa Cruz Naranjo, Santa Rosa, Guatemala. Many consider the cup to be smooth or flat. This coffee varietal adapts well between 3,500-5,500 feet.
Pache colis - Pache colis was found in Mataquescuintla, Guatemala in a farm consisting of Caturra and Pache comum. The coffee fruits are very large and the leaves are roughly textured. Pache colis provides some resistance to phoma. It has secondary and tertiary branching, and typically grows to 0.8-1.25 m. It adapts well to altitudes of 3,000-6,000 feet with temperatures between 20-21°C.
Catimor - Catimor is a cross between Timor coffee (resistant to rust) and Caturra coffee. It was created in Portugal in 1959. Maturation is early and production is very high with yields equal to or greater than the yield of other commercial coffee varietals. For this reason the method of fertilization and shade must be monitored very closely. The Catimor T-8667 descendants are relatively small in stature, but have large coffee fruits and seeds. The Catimor line T-5269 is strong and adapts well to lower regions between 2,000-3,000 feet with annual rainfall over 3,000 mm. T-5175 is very productive and robust, but can have problems at either very high or very low altitudes. At low altitudes there is almost no difference in cup quality between Catimor and the other commercial coffee varietals, but at elevations greater than 4,000 feet Bourbon, Caturra, and Catuai have a better cup quality.
Kent - Kent is used for its high yield and resistance to coffee rust.
Mundo Novo - Natural hybrid between Typica coffee and Bourbon coffee. The plant was first found in Brazil. The plant is strong and resistant to disease. Mundo Novo has a high production, but matures slightly later than other kinds of coffee. It does well between 3,500-5,500 feet with an annual rainfall of 1,200-1,800 mm.
Maragogype - This coffee varietal is a mutation of Typica coffee and was discovered in Brazil. The Maragogype coffee plant is large and is taller than either Bourbon or Typica. Production is low, but the seeds are very large. Maragogype adapts best between 2,000-2,500 feet. The cup characteristics are highly appreciated in certain coffee markets.
Amarello - This coffee varietal, as its name indicates, produces a yellow fruit. It is not widely planted.
Blue mountain - Blue mountain is a famous coffee varietal favored for its resistance to the coffee berry disease and ability to thrive in high altitudes. It was first grown in Jamaica and is now grown in Kona, Hawaii. Blue mountain coffee, however, cannot adapt to all climates and maintain its high quality flavor profile.
Analysis of Soil: Correcting Problems
Lime is often used to help correct acidic soils to a pH between 4.5-5.5 in the first 20 cm of soil. When planting coffee, the holes should be covered with 250-500 g of limestone per meter (Mavolta, 199). Production increases of up to 500% have been observed by adding limestone. In Brazil the highest producing plantations had a pH from 6.0-6.5, a cation exchange capacity of 40-50%, and the base saturation in the upper 20 cm was 60% (Malavolta, 198). The requirement for lime can be calculated as follows:
Lime needed = (T(V1-V2)/RPTN)p where
T - meq/100 cm3 of exchangeable H+Al+K+Ca+Mg
RPTN=Relative Power of Total Nutrition. The average is 75%.
p=factor of compensation for depth:
= 0.5 for 0-10 cm.
= 1.0 for 0-20 cm.
=1.5 for 0-30 cm.
(From Malavolta, 198).
To correct problems with acidity below 20 cm deep phosphogypsum is often applied. Mavolta suggest that phosphogypsum should be applied when aluminum saturation is higher than 20% or the participation of Ca in the effective CEC is lower than 40% (Malavolta, 200).
The following guide explains the fertilizer components recommended when planting coffee seedlings:
Before you plant coffee, Mavolta recommends that 80 g of P2O5, 12 g of K2O, 200 g of dolomitic limestone (or 100 g of calcined limestone), 0.2 g of boron, 0.2 g of copper, and 1.0 g of zinc in a 0.4 x 0.4 x 0.4 meter hole (201) in each coffee planting hole. After the coffee plants are established, four applications of 5.0 g of nitrogen, 10-15 cm from the trunk, are recommended (Mavolta, 201). In the first year 10 g of nitrogen and K2O is applied 3-4 times. In the second year 12 g of nitrogen and K2O is applied 3-4 times. After this time the amount of fertilizer recommended depends on productivity and is given in Table 1.
Table 1. Recommended amounts of N, P2O5, and K2O relative to coffee plant productivity.
|Productivity: 60kg bag/hectare2||Nitrogen||Element P2O5||K2O|
Coffee rust, or coffee leaf rust, first destroyed Brazil's crop in 1970. Since the occurance of coffee rust in Brazil, it has spread to every coffee growing country in the world. Coffee rust and its symptoms were first observed in Sri Lanka in the 1860's. Many countries, including Sri Lanka and Ethiopia, replaced much of their arabica coffee with disease resistant robusta coffee. Coffee leaf rust is spread by wind and rain from spores from lesions on the underside of the plant (Mitchell, 84).
The rust diesease in coffee is prevented by spraying with copper-based fungicides at 3-5 kg/ha at 4-6 week intervals during the rainy season (Mitchell, 85).
Coffee Berry Disease
Coffee berry disease was first discovered in Kenya in 1920 and is caused by the virulent strain of Colletotrichum coffeanum (Mitchell, 85). The fungus lives in the bark of the coffee tree and produces spores which attack the coffee cherries. Spraying has been determined to be the best way to avoid the coffee berry disease. Captafol and copper-based fungicides have been effective. The Kenyan coffee hybrid Ruiru 11 is resistant to both coffee berry disease and coffee leaf rust.
Each year coffee is harvested during the dry season when the coffee cherries are bright red, glossy, and firm.
How to Harvest Coffee Beans
Ripe cherries are either harvested by hand, stripped from the tree with both unripe and overripe beans, or all the coffee beans are collected using a harvesting machine. These processes are called selective picking, stripping, and mechanical harvesting, respectively. To maximize the amount of ripe coffee harvested, it is necessary to selectively pick the ripe coffee beans from the tree by hand and leave behind unripe, green beans to be harvested at a later time.
For more information about coffee harvesting equipment or the methods of coffee bean harvesting, read "Coffee Harvest" by Michael Clark.
++Brazil's Process of Coffee Bean Harvesting
In Brazil, harvesting the same coffee tree several times is less cost effective than separating and discarding the unripe or overripe cherries. Therefore, Brazil typically harvests using the stripping method when 75% of the coffee crop is perfectly ripe. Stripping is feasible and cost effective in Brazil due to the uniform maturation of Brazilian coffees. In stripping, the coffee beans are pulled from the tree and fall to the ground where they are caught by sheets. The beans are removed from tree debris by tossing the coffee in the air allowing the wind to carry away sticks and leaves. The coffee is then put in 60 L green baskets, which is the tool are measurement used by coffee producers to determine wages. Some coffee estates, such as Fazenda Monte Alegre in Sul de Minas Brazil, have a computerized system to determine wages for picking coffee beans. This system accounts for the amount of coffee collected from each person, the difficulty of the coffee harvesting conditions, and the production of the region being harvested.
About 12-20 kg of export ready coffee will be produced from every 100 kg of coffee cherries harvested.