One of the biggest challenges facing the coffee sector is poor harvesting. Farmers harvest immature coffee and mix it with mature beans.
This kills the quality of the produce. During harvesting, most farmers kuwulula (harvest everything on the twig) and yet, coffee should be ‘picked’. That is only pick the ripe beans and leave the rest. Mature coffee beans are cherry red.
The green beans should be left on the tree to ripen further. Always pick, do not strip. When you pick immature coffee, you lose on two sides.
On one hand, you lose at least 30% of the weight you would have got if you harvested them when mature since immature coffee weighs less. On the other hand, you also lose customers if they discover that you harvest immature coffee.
Immature coffee is not only light, but also tastes different from the one that is mature.
- Do not let coffee beans drop on the ground during harvesting to minimise contamination. Tarpaulin or other soft sheets must be spread on the ground below the coffee tree to avoid coffee beans from dropping to the bare ground. If the coffee beans drop to the bare ground, they should be picked carefully.
- Remove all green beans, leaves, twigs and foreign matter from harvested beans. Pick the coffeee regularly, that is every two weeks, to get good yields and better quality.
The ripe coffee fruits (cherries) go through a number of processes to extract the beans from their covering of pulp, mucilage, parchment and film to improve their appearance.
The resulting clean coffee can then be roasted and ground to obtained the coffee powder fit for human consumption. There are two main techniques used to obtain clean coffee, that is, wet and dry processing.
The real implications of poor postharvest handling are seen at the grading stage, when good quality coffee is separated from the poor quality one. Coffee is graded in different ways, however, the best grade is 18 and above.
The process involves the use the colour and smell of the green coffee to give an indication of the botanical species, age of the crop, husbandry, handling and processing conditions.
The sizes of coffee beans range in descending order from screen 18, screen 15, screen 12, screen 11.9 and B.H.P (broken half pieces). The bigger the size, the higher the quality of the coffee. For example, if your coffee is screen 25, then that has a higher quality compared to screen 12.
The bean size is a product of the botanical species, age and husbandry practice. The bean size and weight also determines the out-turn at processing level.
If a farmer selected the right variety, nurtured it well and harvested only mature, ripe beans, then he is likely to get a higher grading, which also fetches more money.
The amount of moisture is measured by a moisture metre which is calibrated in percentages. Moisture metres can be bought from shops at sh50,000. The moisture content is a function of drying, storage and transportation conditions.
This is when farmers who never properly dry their coffee realise their folly. If the coffee beans are stored when they are not properly dried up, that also affects the final flavour of the product.
The final grading involves the liquor content of the product. The liquor content is determined by carrying out cup-tasting.
The liquor quality is a function of the coffee variety and crop husbandry, especially soil management.
Coffee is packed in standard sacks of 60kg before it is stored. Coffee must be stored in a well-aerated, covered area, once it is dried properly. The structure should not have water leaking through it. If you store your coffee is a leaking shelter, then it will get mouldy and loose the flavour.
It is not expensive to create a good storage facility for your coffee at homes. All you need is the space, depending on the volumes that you harvest, plus the jute/gunny sacks to put it in.
The floor of the storage facility must be free of any other contaminating elements such as soil and stones. Use pallets at least a feet above the ground to rest on the sacks.
In some instances, farmers store coffee in the same shelters with animals. This is bad because it affects quality. For instance, coffee dealers have received coffee beans mixed with goats droppings. Do not keep coffee in houses shared by animals because they will contaminate the beans. Others elements to avoid include;
- Products such as beans, soya etc
- Oily elements in the storage area
- Keep fumes, for example generators away
- Well-dried coffee can be kept for a year.