COFFEE BEAN – HARVESTING AND PROCESSING
With great curiosity and enthusiasm Grandpa and Rohit are off to visit Mr. Krishna to observe coffee harvesting and processing that are taking place in his estate. The whole process takes a while so grab some coffee and enjoy this journey.
This process is carried out during the dry season between Nov – Feb for the Arabica variety and Dec – Mar for the Robusta variety. Processing of the coffee is greatly dependent upon how it is sold/consumed. For instance, whether it is meant for mass consumption or is a speciality coffee.
“Soon after the flowers fall, the cherries start to grow, slowly changing its colour from green to red, maturing in a period of 8 months.
“The coffee cherries are picked soon after they are ripe,” said Mr. Krishna“How do you know if a cherry is ripe?” asks Rohit with great interest. Mr. Krishna picks a ripe cherry amongst many that are being picked and shows that when you gently press a ripe cherry the seeds pop out through the skin. This is how you identify ripe cherries.”
“While it might take a long time for someone like us to pick the ripe cherry, the workers on the farm are skilled enough to spot and pick the cherries very quickly. Rohit and Grandpa gaze at the workers busy picking hundreds of cherries from each branch of a plant and repeating the process on all the plants.
DID YOU KNOW?
A good picker can pick about 50 – 100 kgs of coffee cherries per day that produces 10 – 20kgs of raw coffee.
“There are three different ways to harvest coffee cherries:
- Selective Picking – This is a labour-intensive process that involves skilfully picking only the red ripe cherries by hand and is mostly followed for picking the finer Arabica beans. The labourers go around the farm for 8 – 10 days picking only mature cherries and therefore the labour cost is high. A small percentage of undesirable cherries get picked even by the most skilled labourers.
- Stripping – This method is employed for picking cherries that are meant for mass consumption. The workers hold the branch and pluck all the cherries at once dropping them over on large sheets of polythene. Both ripe and unripe cherries are picked while stripping. This is followed for picking both Arabica and Robusta variety cherries that grow in large bunches and processed for mass consumption.
- Mechanical Harvesting –One cannot implement this method for coffee grown on hills however, for countries like Brazil, which has a relatively flat land uses tools to harvest the crop. In this method too both ripe and unripe cherries are plucked.
“Now that the harvest is ready, it should be processed within 10 hours to prevent fermentation within itself. The unripe and overripe fruits should be removed before they are processed to ensure good quality of coffee.
“Before going into the processing details it is important to understand the structure of the coffee fruit. The outermost layer that is red or green in colour is also referred to as fruit skin. The next layer is filled with thick sticky mucilage. Just below the mucilage lies the inner skin or layer. A very thin layer of parchment lies under the inner skin. The last layer is the silver skin which covers the beans.
“Processing is carried out in two different ways – wet processing which is most commonly followed for the Arabica variety that results in ‘parchment coffee’ and dry processing followed for the Robusta variety that results in ‘cherry coffee’. The processing step has to be carefully carried out, paying attention to the undesirable cherries at every stage to ensure uniform cup quality.
“Wet processing – As the name suggests, water is used primarily in this method to process coffee. The coffee thus produced is called fully washed coffee. Arabica coffee and speciality coffee, in areas with abundant supply of fresh water, is mostly processed using this method.
“The fruits are first ‘washed’ and then ‘sorted’, separating the floaters (the overripe cherries) from the sinkers (the ripe and green coffee berries). The overripe and green cherries are often dried as cherry and processed.
“The second step is called pulping which involves removal of the outer fruit skin by directing the cherries through a de-pulper. A slight pressure gently squeezes the fruit when the skin breaks and is depulped. The residue from this step can be used as compost.
“The third step involves removal of the mucilage using various methods - most commonly by fermentation for 24 – 72hrs depending on the weather conditions and the coffee variety. This step is called de-mucilization. After this step the coffee is thoroughly washed for about 3- 4 times with fresh water to remove the mucilage. An additional step of soaking may be carried out to remove any traces of mucilage.
DID YOU KNOW ?
In areas with intense dry weather like India& Ethiopia the coffee is sometimes dried on the trees and later dry hulled which results in a fruity taste developed due to the prolonged contact with the cherry pulp.
“Next, the coffee with its parchment skin is evenly spread to dry on large concrete ground or on polythene sheets. Surfaces such as earth should be avoided for drying directly because coffee absorbs foreign taints and produces those flavours. The beans are raked every hour for even drying for about 7 – 10 days until the moisture is reduced from 60% to 11%. This step is very crucial as over-drying and under-drying would result in poor quality beans.
“Finally, the coffee is sorted once again to remove dust, leaves, etc. followed by bagging and packing to store them.
“Dry processing – This is the oldest method of drying coffee by placing the cherries directly under the sun. This method uses very little to no water to process the cherries and is practised in areas with ample sunlight during the dry weather and least possibility of rains. The coffee produced using this method is called ‘cherry coffee’.
“Just like the wet processing, the first step involves separating the overripe, under ripe and damaged cherries before the processing begins. The traditional method involves picking them by hand and sorting the cherries while they could be washed under water to remove the floats.
“Once sorted, the cherries are spread evenly on clean drying patios. The berries are raked every hour to ensure even drying and avoid over or under drying. The cherries are covered in the evening and spread again the next morning. It takes about 8 -10 days for the cherry to dry under the Sun.
“The final step involves winnowing to removes leaves, twigs, dirt etc. after which the cherry coffee is packed and stored.
“Both parchment coffee and cherry coffee is further processed. This is secondary processing.
“Coffee has travelled half way through to land in your cup. Read Coffee Bean – Secondary processing to know where it further moves.