Growing and processing coffee seed

There are 2 commercially important species of coffee tree, Coffea Arabica and Coffea Canephora (robusta). Arabica was first cultivated in the Yemen whereas Robusta started in the Democratic Republic of Congo in central Africa.

For the botanist, any tropical plant of the Rubiaceae family which produces coffee beans is considered a “coffee tree”. Over 100 coffee species have been discovered by botanists since the sixteenth century and they continue to discover new wild varieties in the tropical forests of Africa.

Robusta coffee typically grows anywhere from 500m to 1500m above sea level and Arabica between 800m and 2000m. Approximately 60% of coffee grown is Arabica with the most popular types being Typica, Caturra and Bourbon. In the early 1980’s the necessity to develop rust resistant Arabica varieties lead to genetically modified varieties being developed. It is generally considered that higher grown coffees have superior flavour, this also leads to lower productivity and therefore higher price.

With the continued advance of climate change the need for higher yield and more tolerant varieties of coffee trees is constantly being researched in order to meet the ever increasing world wide demand for coffee. This creates a difficult environment for many small farmers who are located in very remote areas and so they don’t have access to these new varieties and advanced growing methods. There is a lot of effort being put in changing this situation to assist these producers. Many coffee growing countries rely on the export sales of coffee to help sustain their economies and as such it is vital they are able to produce enough raw materials to meet demand.

Coffee is cultivated in more than 50 countries in the intertropical belt around the equator. The most important elements required for successful cultivation is the correct balance of annual rainfall and the duration of the dry season. It has been found that slower ripening at higher altitudes along with lower air temperatures or under shading leads to improved quality and therefore flavour. Coffee naturally evolved in the undergrowth of tropical forests but this leads to lower yields and a greater potential for leaf rust.

In the 1970’s farmers switched to full-sun methods where farms were deforested and coffee was planted in dense hedgerows and given heavy doses of fertilizer and pesticides. Whilst this lead to increased yield it soon became apparent that this was detrimental to the environment. Whilst there is still a vast amount of coffee grown in this way many farmers have reverted to the shade grown method as it produces a higher quality of bean due to the longer ripening process and lower air temperatures. Consumers are also more environmentally aware and are looking for coffee that is sustainably grown. The amount of shade that is beneficial to the harvest needs to be carefully managed as too much shade inhibits flowering and fruiting and can result in lower yields. It is however argued that a reduction in yield can be offset by the higher price that can be demanded for a more environmentally produced product. Further benefits of shade growing is often a marked reduction in the need for fertilizers or pesticidesas well as the choice of shade tree often results in another cash crop being produced. Examples of this are wood and bamboo for the construction industry along with edibles, oils and resins. Fruits such as Durian, Bananas, citrus and macadamia nuts are often grown along with orchids. All of which help to supplement the farmers income.

Coffee is susceptible to attack from pests as well as fungi which will result in loss of yield or the quality of the beans. Whilst there are many insect parasites that prey on coffee cherries the main cause of damage is from the Coffee Borer Beetle. The beetle bores a hole in the tip of the cherry and tunnels into the bean itself where it lays its eggs. This not only opens up the bean to fungicidal infection but the larvae feed on the bean causing damage. The most common fungal problem is Berry blotch or iron spot. This occurs where there isn’t enough nutrition especially nitrogen. The fungus generates red lesions from induced early ripening that later turns brown and necrotic resulting in a loss of crop.

Assuming you have the right conditions for growing a coffee tree it will usually take around 5 years for it to reach a point where it will start pricing fruit. The tree will produce lovely white flowers which eventually fall and the fruit begins to grow. This is known as a Drupe and usually contains 2 coffee seeds back to back. The Drupe is green to begin with and will slowly ripen over around 7 months. As they ripen the drupes turn from green to a bright red or yellow to indicate they are ripe and ready for picking. As with most fruit they do not all ripen at the same time so the pickers will work throughout the plantation over several weeks harvesting, by hand, only the ripe cherries.

Whilst the basic flavour of an individual coffee is determined by its variety and where it is grown the next step in the beans journey can fine tune this flavour.  The coffee cherry has several layers covering the seeds: pulp (skin), mucilage, parchment and silver skin. There are two basic methods to process the cherry to get the all-important seeds.

Wet processing

Coffee cherries need to be fermented in order to breakdown the pulp and mucilage in order to remove it. In the wet process this takes place either with or without water. The ripe cherries are placed in large tanks, sometimes with the addition of water, and are usually left for  up to 72 hours for the mucilage to naturally breakdown  The coffee beans are then washed to remove any remaining mucilage and then dried. The result in terms of flavour is a very clean taste. Great care must be taken if the beans are left in water to ensure there is no degradation of the beans which would result in earthy, musty or even moldy flavours.

Dry processing

As the name suggests this process doesn’t involve any water. Instead the beans are left to ferment naturally which can take several days. The beans are then spread out on drying tables or on the floor to dry. This involves manually turning the beans at regular intervals to ensure proper drying. In some countries mechanical drying takes place in the final stages of the process.

There are other more complex methods of production such as Pulped Natural and Honey processed coffees which have been developed to meet the demands of the specialty coffee market. These processes involve leaving varying quantities of mucilage on the beans for different time scales to achieve specific flavour profiles. The main benefits of these methods is more refined sweetness, acidity and fruitiness. These processes need much more attention to detail and can be labour intensive resulting in considerably more expensive raw coffees.

Regardless of which method of formation is used the finished parchment has to be removed to finally get to the actually coffee bean. This process is called hulling and is nearly always done by machine. Once this has been completed the raw beans can be bagged in sacks ready for export. As you can see there is considerable cost and expertise required to process the ripe cherries which for a large number of farmers is way beyond their experience or means. This results in a lot of the them sending their crop to large processing plants in order to arrive at the finished product. The growth of the specialty market has however allowed some producers to manage their own processing and achieve much better financial rewards for themselves in the increase value of the finished product.

Indian monsooned coffee

This special coffee was launched by India back in 1972 long before the specialty market emerged. This distinctive coffee was discovered very much by accident. Sometime around 1850 a consignment of coffee left the Malabar coast bound for a Scandinavian buyer. This was a journey of around 6 months and involved sailing around the Cape of Good Hope through the monsoon rains and eventually emerging from the Arabian Gulf. The raw beans packed in jute sacks absorbed moisture whilst in the holds of the vessel which caused the beans to swell in size, undergo a chemical change as well as turning a creamy golden yellow colour. On arrival in Scandinavia the beans were roasted and the customers grew accustomed to the unique flavour of this coffee. Over time the way coffee was transported changed with containerization as well as short shipping times, this meant the coffee arrived without getting the benefits of the monsoon moisture and resulted in a very different taste profile. Customers complained and officials from India were despatched to try and ascertain what had gone wrong. It was only then that they realized that the effects of “monsooning “ had resulted in this very distinctive flavour.  Nowadays the monsooning process is highly controlled and carried out in vast warehouses on the West coast of India between June and October. Coffee from the latest harvest is chosen and the beans are spread on the floor and turned regulary. They are exposed  to the moisture and salt laden winds for about a week. Once they have changed size and colour they are bagged and then left for more than a week to absorb even more moisture from the monsoon winds. The bags are then emptied and the whole process is repeated until the beans have achieved the correct golden colour to develop their unique flavour.