Climates suitable for coffee cultivation

Most coffee grown is made up of two species: Coffea arabica (Arabica) and Coffea canephora var. Robusta (Robusta), with the former making up 70% of all coffee grown globally, and the latter encompassing the remaining 30%.

The production and productivity of both species are largely dependent on the climate for attain high yields and quality.

Temperature and rainfall are important variables as the onset of the dry season and drops in temperature are key in terms of the plant flowering and, thus, producing beans.

Arabica coffee evolved in the cool shady environment of the Ethiopian highlands, where this region has well-distributed rainfall patterns, ranging from 1400–2000 mm for two thirds of the year, with the last third being the dry season and coinciding with the coldest months. The optimum temperature range is about 15 to 24 °C with a precipitation of 1500 to 2000 mm per year. Arabica coffee can tolerate temperatures as low as 15 °C and up to 25 °C.

Arabica coffee needs more than seven months of rainy weather but a relatively high temperature for an abundant differentiation of flower buds. The deep root system permits reasonably good drought tolerance.

Robusta is slightly hardier, as it evolved in lowland equatorial Africa, but grows well in areas with abundant rainfall of about 2500 mm per year. Robusta’s optimum rainfall is between 2000 and 2500 mm. For robusta the rainfall should be well distributed as the plants are shallow rooted. The optimum temperature range for robusta is 24 to 30 °C, but it is more sensitive to lower temperatures. Climate disturbance have led to fluctuations in yield in almost all the coffee growing countries.

Both coffee species, Arabica and robusta tolerate shade and share quite similar growth requirements with various forest crops and trees, thus predisposing them to be grown in agroforestry ecosystems. Growing coffee under full sun with little or no forest canopy causes the berries to ripen more rapidly and the bushes to produce higher yields; this requires shade clearing and increased fertilizer and pesticide uses.

The possible yield and quality of coffee is determined by weather condition. The extended drought periods, which resulted in the reduction of coffee amount and quality. In other cause of climate change such unreliable precipitation throughout growth stages of the crop, be able to influence the easy to discover the soil water and reduce of the crops production.
Climates suitable for coffee cultivation

Timing of the roasting process

Roasting is a process of exposing the green beans to a heating process that is  rapid enough to drive off the free and bound moisture and later the dry bean is heated above 180 °C to a moisture level of 2 to 2.5 %. The amount of time that the beans remain in the roaster determines the strength and flavor of the brewed coffee in the cup.

Actual contact roasting is no longer importance because heat transfer is uneven and the roasting times required are long (20-40 min).

In the contact convection roasting process (roasting time 6-15 min), efforts are made to increase the convection component as much as possible by suitable process management. Centrifugal roasters, revolving tube roasters, fluid-bed roasters etc. are used either batch or continuously.

In the new short-time roasting process (roasting time 2 to 5 min), the heating–up phase is significantly shortened by improved heat transfer.

What is important is to generate and control the correct temperature at the right moment then stop when the aroma has fully developed and the color of the coffee is homogenous throughout the whole bean.

To cater to different tastes, five different roasts have been developed. It is a rundown from very light to very dark.
*Cinnamon roast
*Regular roast
*City roast
*Dark roast
*French roast
Timing of the roasting process

Coffea Canephora

Coffea Canephora
Coffea canephora, which produces the popular robusta beans, is the second most important variety of the coffee plant.

Like its arabica cousin, C. canephora can grow tall; if left to its own device, it can attain a majestic thirty feet in height.

But like the Arabica plant, it is kept to about eight feet in height to allow for harvesting.

In other ways, too, the robusta plant resembles the arabica plant.

C. canephora doesn’t deliver a crop until three to five years after it is planted, after which the fruits take almost a year to mature. And the plant can continue to bear cherries for twenty to thirty years.

Like C. arabica and C. canephora appreciates sixty inches of rain per year. However, this plant likes it considerably hotter than its arabica cousin, and also tolerates higher humidity.

Grown mainly in West and Central Africa, Southeast Asia and parts of South America, robusta plants do best in equatorial conditions with temperatures ranging from the mid- seventies to the mid eighties, and altitudes ranging from sea level to 3,000 feet.

They also differ in that they are both more resistant to disease and higher yielding than robusta plants. The typical robusta tree yields as much as two to three pounds of beans per year – about twice the amount produced by an arabica plant.

Moreover, at 2 percent caffeine by weight, the caffeine content of robusta coffee is higher than that of arabica.

Robusta beans are considered inferior to arabica because they are far less flavorful, with a distinct bitterness.

This is why robusta beans are less expensive than arabica beans and are often used in lower grade commercial coffee blends, as well as in the processing of many instant coffees, both flavored and unflavored.
Coffea Canephora