To achieve high quality coffee production standards, farmers must carry out good crop agricultural practices which include careful harvesting and post-harvest handling.
The farmer should harvest only red, ripe coffee fruits and process them as soon as possible.
Processing involves the extraction of beans from the fruit either soon after harvesting when they are still fresh or after the coffee cherries have been fully dried.
Dry processing is removing beans from the coffee cherries after drying and wet processing is the extraction of the beans before drying.
After wet processing the coffee beans are dried under the sun for up to two weeks. The basic thing is to ensure that it dries up to 13-14 per cent moisture.
Dry processing of coffee is the oldest and most commonly practiced method by farmers in Uganda.
The cherries are spread out under the sun to dry for up to two weeks if the weather conditions are bright.
Uganda Coffee Development Authority (UCDA) Corporate Communications Manager, Laura M Walusimbi says, “The drying process should begin immediately after harvest to avoid the development of undesirable taints and moulds in coffee.”
The cherries are spread out to dry in the sun on clean, suitable drying surfaces such as tarpaulin sheets, mats, clean cemented floors, or raised drying racks.
Advantages of racks
Joseph Nkandu, the executive director of National Union of Coffee Agri-business and Farm Enterprises (NUCAFE) is a practicing coffee farmer who also dries all his coffee on drying racks. The best method of drying coffee is using drying tables or racks. This technology is efficient for both the wet processing and natural coffee processing methods.
On the drying rack, coffee is spread thinly on raised wire mesh racks. This allows air to pass through all sides of the coffee as it dries much faster. The coffee on racks can easily be turned about by hand and the drying that takes place uniformly.
This method is cheaper compared to electric driers and more environmentally friendly compared to diesel driers which rely on fossil fuel.
Using raised beds allows for convenience since it is easier to collect the coffee once dry and also cover the coffee on the beds with tarpaulins in case of rain.
This method allows for management of coffee in big quantities, which is an important measure for ensuring traceability and it also ensures that quality is not compromised since coffee at different moisture levels can be dried on separate beds.
Once coffee is raised off the ground, the brilliance and cleanness of the coffee is preserved and transferred into the coffee cup.
With this the customer is assured of exceedingly pleasant taste, sparkling acidity, strong aroma and rich, creamy body in the cup.
Sufficient air flow that occurs when coffee is dried on racks prevents heat accumulation, over fermentation and oxidation that generates aldehydes and ketones with unpleasant odours often observed in coffees dried on cemented floors.
Drying coffee on raised beds prevents contamination from soil living organisms, small ruminants, and poultry.
It also ensures that once dry, the coffee does not pick up moisture either from the floor or from the tarpaulin. Having achieved this, farmers in their households are able to prevent moulding of coffee during drying and storage.
Lastly, raised wire mesh racks last long and longer more than 10 years before they are replaced.
However, coffee drying racks with wire mesh base complete with tarpaulin sheets for covering the coffee in case of rain are quite expensive and beyond the reach of most small holder farmers who should dry their coffee on mats or clean cement floors.
It requires strong timber, wire mesh, tarpaulin, and good workmanship to make good coffee drying racks and Nkandu recalls that he could have spent close to Shs8m on the racks in his farm house compound. He said the expenses depend on the size and number of racks the farmer believes to be enough for the average amount of coffee harvested on the farm.
Drying on the racks ensures that the coffee is free from dust and animal contamination. It is important to avoid areas with high moisture content.
The coffee should not be rewetted at any time during the drying regime. The drying coffee should be stirred frequently to ensure it dries uniformly.
The farmer should endeavour not to rub it as this will cause abrasions and the coffee will turn dark fast giving it the appearance of having dried before its time.
It is also important to ensure that the coffee is not dried or stored near anything with a strong odour as coffee picks odours easily.
“Coffee should be dried to a moisture content of 13-14 per cent before it is taken to a huller to remove the husks. Good harvest and post-harvest practices result in a high cup quality,” says Walusimbi.