• From Plantation to Washing Station

Cultivation of Coffee Trees

The cultivation of coffee trees is made by each producer member on his/her farm with traditional farming methods. Tilling is done by hoe, weeding and, harvesting is manual. These methods are practiced by all coffee producers of COOPAC.

Area Cultivated

The total area under cultivation is 1,500 ha and the average area cultivated by small producer members of COOPAC varies between 0.2 and 15 ha. Small producers cultivate Bourbon Mayaguez variety of Arabica coffee either by cuttings or by seeds - seeds are selected from seed gardens of ISAR (High Institute of Agronomy of Rwanda).

Nursery Trees.

Once seeds are selected, COOPAC proceeds with creation of seedbeds and nurseries. Seedlings are evolved from the end of October to early November. Seeds spend 3 to 4 months and then seedlings are carefully removed and sorted before being transplanted into nurseries. Seedlings spend there eight months before being transplanted into the farms.

• Planting Young Coffee Trees

Transplantation is most often in October-November during the short rainy season and ends no later than early December and that, with manure in a 40x40x40 cm hole. The density of coffee trees in the plantation is of 2,500 plants per hectare.

• Maintenance of coffee
  

Maintenance at coffee feet is done by weeding and hoeing for protection of coffee trees against weeds. Then mulching is done to protect coffee trees against erosion and sunshine (good mulch should have and maintain a thickness of 10-15 cm. It also records the contribution of organic matter for fertilization and increase yields.

Pruning is done to give coffee tree a solid structure, able to produce and bring bountiful harvests, regular and well distributed. Better harvest gives 5 kg of coffee cherries, one kilogram of parchment per coffee tree.

There are three kinds of pruning :

1. Pruning or false Agobiada or Areuse: it is done one month after planting. Young coffee trees of 0.8 to 1 meter are arched east-west direction to cause the occurrence of discharges at the base of the trunk (10 to 20 cm of soil). We choose three releases when their height reached 50 cm and the stem-mother is also cut or removed.

2. Pruning of production: it aims to keep coffee trees in the form adopted. It includes the following phases: periodical sucker cutting and cut dead branches at the lower base of trunk.

3. Regeneration pruning or renewal of stems: its aim is the restoration of stems. It is made after a production cycle of 5 - 7 years. The first year, 2 stems out of 3 are chopped down leaving more inclined stem with a promise of harvest. A year after the onset of shoots, the remaining stem is removed.

Wet Processing System

• Reception and Selection

After harvesting (great harvest from February to May or small harvest from October to December), each coffee producer carries his/her cherries to the nearest COOPAC washing station for sale. Every purchase is preceded by an earlier control of quality of cherries in baskets or bag by producers themselves.

On arrival of cherries at the station, a second strict control is performed in the cherry bucket at selection countertop level for the sole purpose of preserving coffee. At the first stage only red cherries harvested the same day are accepted ; duration from crop to reception does not exceed 8 hours. This leaves a margin of time because after 12 hours fermentation begins in the pulp which spoils the quality. Green or yellow, black or faded cherries harvested the previous day are removed.

At the second stage, cherries are poured into containers half water-filled. Dense cherries dense under water are retained and floated cherries are thrown out.

• Weighing

Good cherries selected and accepted pass through the weighing room where producer and two officers committed to weighing, each with its balance, weigh independently and communicate weight to the cashier who, in turn, gives the producer a receipt which entitles him to be paid the same day or the next.

• Pulping and Pregrading

Pulping consists of removing exocarp from cherries. This is a tricky process because if beans are damaged, they become vulnerable to bacterial attack and to undesirable elements penetration.

Coffee cherries are dropped into reception tanks by water driven by gravity flows them to the chain of pulper. Pulper separates different qualities depending on density of beans. The first quality that is the densest ones that represent 85% of production, second quality, 10% and third quality, 5%.

• Fermentation

Fermentation consists of two distinct processes: dry fermentation and wet fermentation.

Dry fermentation or "degumming" eliminates the mesocarp from cherries which sticks to parchment coffee after pulping. This takes 12 hours in the fermentation tank. After those 12 hours, cherries are washed manually with water to remove the remaining mucilage. The mucilage-laden water is discharged to percolation pits where it seeps, protecting the environment.

Wet fermentation or fermentation under water immersion or pulped beans after degumming aims to improve the color and the taste of the coffee shop allowing exosmose internal constituents including terpenes and various phenomena generators tastes. Beans ferment under water for 24 hours. After those 24 hours, wet parchment beans are washed to release the mucilage that still sticks. Then they are sorted manually in order to identify beans that have defect and floating parchment that were not detected previously.

• Washing and Gradage

The washing down the drain channel consists of washing manually and grading in order to remove the mucilage fluidized and prevent that the brown mucilage can enter the bean.

• Soaking

Soaking in water is done in order to eliminate any trace of mucilage on the surface of the parchment and enhance the quality of coffee. This is necessary because during draining and even drying, mucilage can adhere to parchment and cause a significant detrimental fermentation to the taste of green coffee. Soaking takes about 16 hours but if the bottleneck at the pre-drying, soaking can be extended to 48 hours, provided that the coffee is actually under water.

• Pre-drying and Draining

While the coffee is still damp, it is easier to detect defaults. The draining and pre-drying are successively done on the same pre-dryer while beans are shaded from sun and are designed to remove water from the outer parchment. During these operations, water content fells down from 100 to 47% between 3 and 6 hours. Duration of this operation depends on the thickness of the layer, the frequency of manual riddling and atmospheric conditions.
Draining is used to keep quality because if wet parchments leave soaking tubs and are exposed to the sun, they would explode and lose quality.

• Drying

After pre-drying, coffee parchments are carried to drying tables in baskets of 20 kg – trellis tables. Drying process lasts between 10 and 15 days depending on sunlight. Coffee parchments are continually turned manually for drying being uniform unless there is rain or sunshine. The maximum duration is dependent on climatic conditions.

Drying is an operation that determines the color and appearance of green coffee, tasting quality
and resistance to conservation. Coffee parchments are removed from coffee tables only when the
humidity varies between 10 and 12.5%.

• Storage

After drying, the coffee husks are packed in plastic bags and transported to the washing station to the warehouse located at headquarters in Gisenyi. Transportation is by lake.

• From Dry Processing to Export

HULLING

Dry parchment coffees are carried out of the warehouse and carried to the dry processing unit to be hulled. Hulling is carried through the following steps and machines :

•    Reception : This is the quality required is received.
•    Pre-cleaner : This is the machine that separates the coffee beans with stone and other products such as beans.
•    Destoner :
•    Hullers : Two machines that perform dissect the coffee husks to obtain green coffee.
•    Catadors : Two machines that are used to differentiate green coffee according to the weight and density.
•    Grader : Here is the size. Green coffee is distinguished by seed size in grades below:

Grades         %
• 18 +          27.53
• 18             34.41
• 17             25.18
• 16               5.48
• 15               5.44
• 14               1.97

The first quality includes three grades: 16, 17, 18 and beyond. The second includes grades between 14 and 16 and the third, grades below 14.

Packaging

On leaving dry processing unit, green coffees are packaged in jute bags of 70 kg and stored in COOPAC warehouse in Gisenyi before being carried to OCIR-CAFE warehouse in Kigali.

Export

After coffee processing, COOPAC sends a sample per production batch to its regular buyers. The customer/buyer, after testing the sample in his laboratory, places an order. Depending on the quantity ordered, COOPAC carries green coffee to OCIR-CAFÉ warehouse in Kigali, 150 km from Gisenyi. Then green coffee is manually resorted and packed in jute bags of 60 kg each and loaded into 20-feet container truck for shipment by road to the port of Dar-es-Salaam or Mombasa. Each container contains between 300 and 320 bags or 18,000 kg and 19,200 kg of green coffee respectively.
Transport of green coffee from dry processing in Gisenyi to the warehouse of OCIR-CAFE is done via a 20-ton truck or a 5-ton truck belonging to COOPAC or via vehicles hired. Exportable coffee is transported by road from the warehouse of OCIR-CAFE in Kigali to Dar es Salaam or Mombasa and by sea to the final destination.