How post-harvest processing is changing Nepal’s coffee ?

How post-harvest processing is changing Nepal’s coffee

The true potential of the specialty grade coffee is not only determined by where it is grown but also shaped by what happens after the coffee is harvested. In fact, the post-harvest process largely determines the quality, consistency, and market value of the beans. In Nepal, farms use different processing methods such as washed fermentation, natural process, honey fermentation and so on. There is a journey in the post-harvesting, which includes the handpicking, fermentation, drying, sorting, and storing that preserves the best flavour profile in coffee.

The journey begins with selective handpicking, in which only the red ripe coffee cherries are selected. In Nepal, the coffee usually comes from smallholder farms from the hilly terrains, which makes handpicking the most effective method for maintaining the quality. Cherries in hilly regions grow and ripen slowly for which farmers have to be patient to pluck them at the right time. Picking the right cherry is a very important task as under-ripe cherries fail to roast properly, causing the presence of quakers. Quaker is an underripe, undeveloped coffee bean that fails to brown properly during roasting and stays pale, tan, or peanut-colored. A single quaker in 350 grams coffee is enough to discard the whole lot from the specialty grade.

The next step is the controlled fermentation, which is essential for developing a desirable flavour profile while also preventing defects like sour and black bean defects. Under-fermentation does not let the mucilage layer around the coffee bean to fully break down which leaves beans with underdeveloped flavour compounds. This results in a brew that tastes grassy and the beans lack sweetness, acidity and complexity, which is expected from a specialty roasted coffee. Over-fermentation causes the sugar to break down excessively, resulting in the coffee often being “fermenty”.

Additionally, drying is equally important to control the moisture level in the coffee. Drying also helps to prevent mold growth, and it preserves the bean integrity. For the coffee to be graded as specialty grade, the beans’ moisture level should be between 9% to 13% as per Specialty Coffee Association. However, 10% to 12% is widely recognized by experts as the optimal moisture level. Moisture level in green coffee beans is crucial because moisture level affects how the coffee tastes and how it roasts.

For the beans to have a consistent moisture level, farmers regularly turn the beans and protect them from excessive heat during drying. Most of the farms in Nepal dry their coffee in the raised beds until they reach the ideal moisture content level.

When the beans reach their ideal moisture level, the beans are then sorted. Typically, the objective of sorting is to eliminate any primary and secondary defect beans. Primary defects include full black beans, full sour beans, beans with fungus or mold damage, and severe insect damage. While secondary defects include partial black and partial sour beans, quakers, slight insect damage, floaters and broken, chipped, or cut beans. SCA policy tolerates none of the primary defects while only 5 secondary defects are tolerated in 350 grams of coffee beans. Nepalese farms are seen to use both machine sorting and hand sorting methods. Farms in Nepal use hand sorting methods to eliminate the primary and secondary defects, while machine sorting is used to differentiate the beans as per their screen size.

The final crucial step is the storage and quality preservation in which beans are stored as parchment coffee in clean, dry, and well ventilated facilities. Farms in Nepal use hermetic liners to protect their coffee from losing their original aroma and flavour profile. The hermetic liners help the beans to be protected from moisture level absorption, contamination, quality deterioration before they go for hulling and further processing.

Farms in Nepal are putting extra effort into maintaining the traceability of beans based on farms, harvest date, or processing method. This is essential for the Nepalese Specialty Coffee industry as it will allow buyers to reward quality and transparency.