Coffee should be black as hell, strong as death and sweet as love. – Turkish Proverb
Coffee grows in tropical regions between the tropics of Cancer and Capricorn in what is known as the ‘bean belt’. Arabica generally likes higher altitudes of 550 to 1,950 metres (1,800 to 6,300 feet); anything above 1200 metres is ideal. Coffee grown below about 1,000 metres may be of inferior quality, although Hawaii is an exception. Robusta varieties prefer a lower elevation of 180 to 750 metres (600 to 2,400 feet) with warmer temperatures. Within those ranges, the altitude profoundly impacts the coffee. High elevation coffee will produce more acidic, aromatic and flavourful coffee; lower elevation coffee tends to have less acidity and a more muted character.
Coffee plants are evergreen shrubs that can grow up to 4-6 metres tall with broad, glossy leaves and white flowers. Older varietals take 3 to 4 years to bear fruit while recent varietals will bear their first crop two years after being planted out.
The fruit, the coffee cherry, ripens around eight months after the emergence of the flower. The cherries are harvested once they have changed colour from green to deep red. In most coffee-growing countries, there is one major harvest a year. A few countries, including Colombia, have a primary and secondary crop: the main harvest is from April to June and the smaller one from November to December.
Just as there are two main kinds of coffee, arabica and robusta, there are two main methods of coffee cultivation: sun-grown and shade-grown. Shade-grown coffee is the more traditional approach that mimics the natural way coffee trees grow in the wild, underneath a forest canopy. Farmers, particularly in Brazil, began growing coffee in full sun in the 1970s to increase yields and production.
Coffee trees growing in the shade of a forest maintain the forest’s biodiversity, particularly its wildlife, and shade-grown coffee often trades at a premium to full-sun coffee. However, the thick forest cover – combined with the steep mountain slopes where coffee grows – makes harvesting more difficult and costlier. It is much cheaper to produce coffee on open flat land, especially if it is mechanically harvested.
There are different degrees of shade-grown coffee production. Rustic shade-grown coffee is where the trees are planted in an existing forest with only the lowest levels of the original forest removed. Once planted, the coffee trees require little care and often no pesticides or herbicides. It is the least capital-intensive method of coffee production. It suffers from a low yield and is quite rare except in India and some of the western coffee areas of Ethiopia.
Traditional polyculture involves planting other (usually food-bearing) trees alongside the coffee trees under a natural forest’s canopy. Commercial polyculture consists of removing or pruning much of the native forest trees to allow sunlight to pass and to give space for the coffee and other crops to grow. The shaded monoculture system is where farmers plant and then prune a single species of tree to provide shade for the coffee trees, allowing them to be grown more densely.
Over the past half-century, growers have developed new sun-tolerant coffee trees and shrubs to combat disease (particularly rust-leaf disease) and provide higher yields. As a result, the percentage of coffee that is shade-grown has been steadily falling. The increase in global production over the past twenty years has almost all been full-sun coffee. Shade-grown coffee fell from 43 per cent of the total cultivated area in 1996 to 24 per cent in 2014. It has almost certainly continued to fall since then.
Coffee is picked by hand in most countries. In Brazil, where the landscape is relatively flat and the coffee fields immense, the process has been mechanised. Mechanical harvesters strip-pick all the cherries from the trees in one go, whether they are unripe (green), ripe (red) or overripe (purple/black). Mechanical harvesting can stress and damage the trees, reducing the yield the following year.
Coffee is sometimes also strip-picked by hand, particularly the lower quality arabica or robusta varieties. Better quality coffees tend to be selectively picked by hand. The pickers rotate among the trees every eight to ten days, choosing only the cherries which are at the peak of ripeness.
Selective hand picking is more labour intensive and more costly; it is used primarily to harvest the higher quality arabica beans. Red berries, with their higher aromatic oil and lower organic acid content, are more fragrant, smooth and mellow. As such, coffee picking is one of the most critical stages of coffee production.
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This is an extract from my book Crop to Cup – Conversations over Coffee now available on Amazon.