Uganda, like most other coffee producing countries sees limited value addition through roasting and soluble coffee manufacturing mainly because there is limited consumption yet the investment is high.
This is why the bulk of the coffee, nearly 90% is exported.
An economical investment in a soluble plant is approximately above $20.0m which is high for some multinational companies that would be interested.
The effort to attract multinationals is constrained by low level of domestic consumption and the fact that they already have excess capacity in the traditional consuming countries.
However, there are other forms of value addition being done at farm level which directly improve the incomes of the farmers such as production of specialty quality, organic and other certified coffees which can double the income.
Low level of coffee roasting is now done mainly in the urban areas such as Kampala to serve the upcoming coffee shops/cafe culture. As consumption grows there is no doubt the value addition through roasting will also grow.
The final flavour of coffee is heavily dependent on how coffee beans are roasted. Roasting is a time and temperature dependent process. The roasting temperature needs to be about 2000C. The degree of roast is usually assessed visually and one method is to watch the thin white line between the two sides of the bean.
When this starts to go brown, the coffee is ready. It is always important to find out the locally acceptable degree of roast in any market.
Coffee beans can be roasted in a saucepan as long as they are continually stirred, but an improvement is roasting the coffee in sand as this provides a more even heat.
Use of a coffee roaster is preferred as it produces a high quality product. The simplest roaster is a tin can with a handle so that it can be rotated slowly over a fire. There are various other roasters suitable for larger scale units.
Grinding is a key value addition process. It underpins the preparation of beverage coffee and other coffee by-products.
Grinding is best done by use of grinding mills, manual or motorised.
There are many manual grinders that can be used to grind coffee. Manual grinders can be attached to a bicycle or treadle to make work easier and increase output.
It is always important to find out the degree of fineness consumers want and the grinding mill adjusted to deliver the desired ground product. Motorised grinding mills involve the use of a hammer plate, vertical plate or hammer mills and are required for large scale production of 100kg of ground product per day.
Apart from exporting green coffee beans, coffee can also be roasted, ground to make coffee powder which is in local coffee shops to prepare coffee drinks. Encouraging of local coffee shops and local people to consume coffee could also help on value addition.
Production of instant coffee is unsuitable for small-scale enterprises as it requires very expensive machinery such as an extractor, a freeze and a spray drier.
Presently, the smallest economically viable instant coffee factory is 1000mt/ year. Machinery can be obtained from countries such as India, China and other European countries.
To produce instant coffee, the soluble coffee solid and other compounds have to be extracted and then dried it to powder or granules.
The extraction of the soluble coffee solids is done using different methods that include use of percolation batteries, countercurrent system or slurry extraction. The extracts can then be dried in a spray drier, freeze drier or a drum drier.