Amid rows of lush green trees covered in ripe red fruits, skilled pickers carefully remove coffee cherries and place them in bushels destined for processing. Once these ripe red fruits have been separated from their trees the clock begins ticking as the possibility of spoilage looms. Therefore transitioning them into a processing stage as quickly as possible is key.
Coffee processing sounds like a rather unimaginative and mechanical step following the rather romantic stage where fruits are nurtured for months on nourishing trees. However, coffee processing is in fact a critical part of the overall value chain, and when done skillfully, one that can add great character and a great deal of flavor to the coffee.
Coffee cherries are generally processed by one of three ways -- washed, natural or honey methods. In terms of natural and honey, innovative small lot farmers have been experimenting with techniques that stretch these processing styles into delicious directions. The following is a brief introduction into some of the key processing methods.
Washed processing involves removing the ripe cherries pulp (skin), and literally washing the coffee beans with water in an effort to remove the fruit's sticky mucilage. The cleaned beans are then put into fermentation tanks to soak in more water generally for 24-48hrs before being laid out on vast patios to dry in the sun. Washed coffees are probably the most common coffees available, as they are known for exhibiting clean, consistent and complex flavor.
Natural processing involves drying the coffee cherry fully intact prior to removing the coffee bean from its skin. This allows all of the cherry's sweet liquid and outer layers to impart a variety of delicious natural flavors to the bean, as the cherry dries 'naturally' under the sun. Natural-processed coffees burst with yummy stone fruits, dried fruits and other amazing flavors!
Honey processing is more commonly found in Central American coffee producing farms. This unique processing method involves removing much of the cherry's pulp (skin), but leaving the sticky sweet inner liquid on the beans to dry in the sun. Like with natural processed coffees, honey processed coffees are filled with amazing natural fruit flavors.
Raisin honey process is something of a marriage between dry the natural and honey processes. The raisin honey process starts with a brief period of whole fruit sun drying until the cherries resemble raisins. Then the skin is peeled and a 2nd fermentation occurs in traditional honey process fashion. This is essentially a double fermentation process that creates naturally sweet coffees.
Ripe red cherries are picked then placed into polystyrene bags where they are left to ferment, become black, and develop their winey character. The coffee is then placed on raised beds to dry to approximately 11% moisture. The coffee rests to allow enzymes to settle and balance, which takes around four weeks. When done right, a winey natural coffee like the TRIBO Colombia is well-balanced with low acidity and a wonderful natural sweetness.
As the name suggests, coffee is fermented in sealed tanks without oxygen. Pressure begins rising as CO2 is created inside the tanks through the fermentation process. Increased levels of CO2 push any remaining oxygen out of the tanks via release valve, creating an oxygen free environment. At this point the theory suggests that the high pressure created by the CO2 essentially injects the coffee cherry's sweet mucilage into the beans. From the farmer's perspective, this process involves a high level of sugars, temperature, pressure, pH and time management. When done right, the results are quite delicious, as the final products generally have distinct acids and striking flavors.
Double anaerobic processing refers to the process by which the coffee goes through “double” or two-stage fermentation in a sealed oxygen-evacuated tank, first in the whole fruit for two days, then after removal of skin and fruit pulp, for two more days.