Processing coffee so separating the coffee cherry’s fruit flesh and skin from the coffee beans is one of the most crucial aspects of farming coffee.
The goal of processing coffee for farmers is to separate the bean from the coffee cherry, also preserve the coffee’s profitability. Even if the coffee was picked perfectly ripe and the harvest has gone really well. Bad coffee processing can lead to defects which decrease the value of the coffee. Some processing methods require more time. Investment and natural resources that others so choosing the right processing method can be crucial decision for a coffee farmer or producer. In this post, Pritish Kumar Halder explains some interesting points about coffee.
Natural – dry process
Also known as the dry process. Natural processing is most old school way to process coffee. After picking the coffee cherries from the coffee trees, they are spread out in thin layers to dry in the sun. The drying stations can be a little different depending on the farm or region. Some use brick patios, others special raised beds which enable air to flow around the cherries. To avoid mould, fermentation or rotting, the cherries are turned regularly. The skin and dried fruit flesh are removed mechanically and green coffee is stored and “rested” before exporting it.
This process is common in regions where there is no access to water such as Ethiopia and some regions in Brazil.
Natural processed coffees definitely adds flavors to the coffee such as fruitiness and sweetness regardless of variety and region. Common flavor notes for natural processed coffee are blueberry, strawberry, tropical fruits and honey but on the flip side.
WASHED – WET PROCESS
Also know as wet processing method, is the other main way to process coffee. In the washed process all of the fruit flesh is removed mechanically from the coffee bean before the beans are dried. Removing of the fruit flesh is done with a machine called depulper. After depulping the beans are put to a water tank where fermentation process will remove the remainder of the fruit flesh. The amount of time that the fermentation requires depends on the climate and altitude. In hotter regions the fermentation will take less time and vice versa. Usually the fermentation requires 24-72 hours and if the coffee beans are fermented for too long, it will have negative effect on the flavor of the coffee. After the fermentation is ready, the coffee beans are washed to remove any leftover flesh and then it is ready to be dried. Drying in the washed process is done similarly as in natural process so in brick patios or raised beds. To ensure even drying the beans are turned regularly as in natural processing. The beans can be also mechanically dried, especially in regions where there isn’t enough sunshine or excess humidity.
Washed process leads to bright and acidic flavors in the cup. Many farmers or producers choose the washed process because properly done it reduces the risk of defects and it’s more stable way to process coffee.
HONEY – PULPED NATURAL PROCESS
Honey process is used commonly mainly in Central American countries such as Costa Rica and El Salvador. The cherries are mechanically depulped. But the depulping machines are set to leave a specific amount of flesh on the beans. After depulping the beans go straight to the drying tables to dry. As there is less flesh surrounding the beans, the risk of over-fermentation is lower than in natural process. But the overall sweetness and body in the cup are increased by the sugars in the remaining flesh. Honey processed coffee have positive attributes from washed and natural coffees; sweetness of naturals and brightness of washed.
This kind of coffee are quite often referred with colors; black, red, yellow and white honey. The color referrers to the amount of fruit flesh that is left on the bean after depulping.
Similar to honey processing is pulped natural process which uses a bit more water and strips the beans fully during depulping. Pulped natural process is mainly used in Brazil.
Anaerobic ( = oxygen-free) fermentation is one of the newest methods to process coffee and has gotten popularity especially among really high end coffee such as competition coffees. Anaerobic process is similar to washed process but the fermentation is done in fully sealed and oxygen deprived tanks. The methods is still quite experimental but anaerobic processed coffees have often wild, unexpected and complex flavors.
This method is similar to the anaerobic and it has been stolen from the winemaking world. The biggest difference to anaerobic process is that the cherries are fermented as whole and the process breaks down the cell walls of the fruit flesh from inside out. All the crazy flavors from the fruit flesh is soaked into the beans during the fermentation and carbonic maceration yields extremely crazy and incredible flavors such as red whine, whisky, banana and bubblegum to the cup.
Sounds something not related to coffee but in fact it means “wet hulled” in Indonesian language. As you might then expect, it is only common in Indonesia. Giling basah is similar process to washed process but the beans are dried to only 30-35% moisture content (11-12 % in washed process). After initial drying the parchment is removed from the beans and the “naked” beans are then dried again until they are dry enough to be stored. Giling basah yields earthy flavors such as wood, mustiness, spice and tobacco which is why it isn’t highly appreciated among coffee professionals.
After the coffee has beans processed, they are still enclosed by the parchment layer. Now the beans’ moisture content is low enough to be stored so that they don’t rotten. Usually the beans are stored in reposo ( dry warehouse) for 1-2 months before exporting. Just before exporting the beans are hulled to remove the parchment. The hulling is done mechanically in a dry mill. After hulling the beans are graded and sorted with machines that examine the size and color of the beans. Once the beans have been sorted and graded they packed into bags. The bags are packed into a shipping container which protects the beans during their long journey to a roastery.
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