HARVESTING AND PROCESSING
A coffee plant usually starts to produce flowers three to four years after it is planted, and it is from these flowers that the fruits of the plant (commonly known as coffee cherries) appear, with the first useful harvest possible around five years after planting.
Once the cherries have reached a level of ripeness where the outer skin turns red, the picking begins. All arabica coffee in Indonesia is picked by hand, whether it is grown by smallholders or on medium-sized estates. As for Robusta coffee, strip picks using machinery are often used whereas the smaller plantations will hand pick the coffee cherries. Hand picking is of course the preferred method as only the choice cherries picked and the pest infected beans and debris can all be sorted out. Beans at this newly picked stage can only last two days before they need to be further processed. This is the processing method most commonly used for Toraja coffee.
The next stage of processing produces “green coffee”. There are two methods that are used to do this: the dry method or the wet processing system. The dry method is predominately used in Sumatra and by small hold farmers in Java, Bali, and Flores. This method involves drying the beans outside under the sun. The beans are laid out either on a concrete pad, or on sacking laid out on the side of the road. Ideally the stacks of bean should not be more than 5 cm high and the beans need to be turned every two hours to ensure correct humidity level is achieved before hulling. It is vital to avoid being rained upon.
The drying process can take several weeks. Over this time the beans are raked and turned as often as needed to ensure a universal drying effect is achieved. Once the outer area of the bean begins to fall off, the coffee is ready to have the pulp removed. It is normally dried until the moisture content of the bean is approximately 11%. The mulching is done by machinery- although some of these mulching machines are still hand driven! The final product is a green bean, about 1/3 the size of the original cherry. The dry method produces coffee that is heavy in body, sweet, smooth, and complex.
The second method of drying coffee is the wet processing system. Wet processing means the bean can begin the final preparation stage immediately after being picked. Instead of drying under the sun the cherries are processed through a water system. This process results in a coffee that is cleaner, brighter, and fruitier. The pulp of the coffee cherries is removed to release the two coffee beans inside. The beans then sit in water for 24-48 hours to ferment. This is the heart of wet processing--when the fine, acidy flavor of great coffee is produced.
The fermenting process softens the outer skin which makes it easy to remove. The system works well although there are often times when the sugar in the beans can ferment, causing the flavor of the beans to be affected. Most large coffee estates in Java use this system as it speeds up processing and generally makes selection of the final green bean much easier. The quality of green bean from wet processing is generally higher.
After fermentation, the remaining pulp is washed off and the beans spread out to dry. The coffee can also be dried in a mechanical dryer, powered by a wood, gas or solar power. As in the dry method the beans need to be dried until the moisture level reaches a[proximately 11%. The coffee is then referred to as parchment coffee and is ready to be warehoused in sisal or jute bags until readied for hulling.
Machines are used to hull the parchment layer (endocarp) from the wet processed coffee. Hulling dry processed coffee refers to removing the entire dried husk -- the exocarp, mesocarp and endocarp -- of the dried cherries. Green coffee can last for years if it is stored in the correct conditions. It is vital that it is not exposed to high humidity as this will cause molding. It can also absorb flavor from other things stored around it so to avoid tainting the taste care must be taken in choosing the warehouse location.