Processing
The type of processing used can vary a lot. This is sometimes based on the country that the farm is located in and the resources that are available.
For example, Ethiopian coffees are often dry processed because water is a scarce resource.
So they favor dry processing more than other countries that have wetter climates.
Coffee beans are processed using several methods before roasting, with the main categories being
A. washed (wet)
B. natural (dry)
C. pulped natural.
D. Honey
E. Anaerobic
F. Monsoon
Each method impacts the final flavor profile of the coffee.
In fact how the bean is processed is probably as important as the type or species of the bean itself.
A. Washed Process (Wet):
1. Depulping: This is done 1st after harvesting.
The outer skin and pulp of the coffee cherry are removed mechanically or by hand.
2. Fermentation:
The beans, still coated in mucilage, are placed in tanks of water to ferment, breaking down the remaining fruit layer. (24 - 48hrs)
3. Washing:
The beans are thoroughly washed to remove the fermented mucilage.
4. Drying:
The beans are dried to a specific moisture content, often using mechanical dryers or the sun.
The drying stage is very very impt. This stage takes up a huge portion of the coffee's life.
The drying stage can be for up to a couple of weeks depending on the conditions.
Sometimes they are laid out on tarps, sometimes they are elevated.
The washed process probably gives the cleanest and truest representation of the terroir of what the coffee can be.
B. Natural Process (Dry):
Also known as "clean natural".
Here, the coffee cherries are harvested and spread out to dry, either on patios or raised beds.
This method is probably the oldest method. They can be left for several weeks like this without removing the seed.
The cherries dry in the sun, with regular raking to prevent spoilage.
They ferment naturally and the cherry that surrounds the seed simply rots away exposing the seed/bean.
Depulping: After drying, the dried fruit (cherry) is removed, and the bean is extracted.
The bean is then left to dry again and its bagged.
It is not washed.
Sorting: The beans are sorted to remove defects.
This is possibly the most difficult method. It's very difficult to control fermentation., temperature,
the weather, etc.
You tend to have lots of fruity notes in these sorts of coffees.
C. Pulped Natural:
In Central America, pulped naturals have come to be referred to as honey processed coffees.
Depulping: The skin of the coffee cherry is removed (often by squeezing the cherry), but all of the mucilage (the sticky layer) is left on the bean. The removal of the skin is typically done within 24 hrs after harvest. There is often less fermentation that the dry method.
Drying: The beans are dried with most of the pulp & mucilage still attached.
The beans are dried to a specific moisture content, often using patios or mechanical dryers.
The coffee will ferment (as it is exposed to air and microorganisms) until it reaches an inhospitable moisture content for them ( typically 11% moisture). The trying time can be as long as 10-15 days.
The exposed fruit material increases risk of taints, spoilage, etc. It requires more labor in drying.
The coffees will also often have an uneven appearance in their green forms, which can be unappealing for roasters who are used to the more uniform cleanliness of a Washed coffee.
D. Honey:
Pulped natural and honey processing are often used interchangeably. Esp in Central America.
Both pulped natural and honey processes involve removing the skin of the coffee cherry
(often by squeezing the cherry) and popping the bean out.
The beans are then dried with some or all of the mucilage (the sticky fruit layer) still attached.
The key difference lies in the extent of mucilage removal.
Pulped natural typically removes only the skin, leaving all the mucilage, while honey processing removes some of the mucilage, with the amount removed determining the "color" (yellow, red, or black) of the honey process.
Since the amount of mucilage left on the bean varies, this has lead to different classifications:
Yellow Honey: Less mucilage.
Red Honey: More mucilage than yellow, less than black.
Black Honey: Most mucilage is left on the bean.
Often associated with Costa Rican coffee production.
The term "honey process" is more recent and has become widely used in various coffee-producing regions.
In essence, both processes aim to create a coffee with a sweeter, fruitier flavor profile than washed coffee, but with less intense and potentially more nuanced characteristics than natural processed coffee.
E. Anaerobic
The anaerobic coffee process involves fermenting whole, de-pulped, or de-pulped coffee cherries in a sealed, oxygen-free environment for a set period.
This controlled fermentation shifts the microbial activity to specific bacteria and yeast that produce distinct acids, alcohols, and esters from the coffee's natural sugars, resulting in complex, fruity, and sometimes wine-like flavors in the final cup.
After fermentation, the coffee is dried using various methods, such as the natural, honey, or washed process, to create a range of flavor profiles.
Biochemical Transformation: The naturally occurring sugars and compounds in the coffee cherry are broken down by anaerobic microorganisms into different byproducts, such as lactic acid and esters.
Absorption by Beans: These flavor-producing compounds are absorbed into the coffee beans, influencing their eventual taste.
After fermentation, the coffee can be dried as a natural (dried with the whole cherry), honey (dried with some or all of the mucilage), or washed coffee (fully de-pulped and washed).
The Resulting Flavor Profile:
Exotic Flavors: Anaerobic processing can produce more exotic and intense flavors compared to traditional methods.
Complex Acids & Sugars: The process yields distinct acids and sugars, contributing to a complex taste.
Boozy or Wine-Like Notes: Some coffees processed anaerobically can have a boozy, oak-barrel, or even whiskey-like note.
Fruity & Aromatic: Expect more pronounced fruity aromas and flavors.
F. Monsoon
Monsoon coffee, also known as Monsooned Malabar, is a specialty coffee from the Malabar Coast of India that undergoes a unique post-harvest process.
During the monsoon season, green coffee beans are exposed to the humid, moisture-laden winds for several months, which causes them to swell, change color, and develop a mellow, low-acidity flavor with notes of spice and chocolate.
History: The process originated in the 18th century when coffee beans were shipped from India to Europe on wooden sailing ships. The long, humid sea voyage caused the beans to absorb moisture and change, which the British eventually found developed a unique flavor.
Modern process:
After harvest, high-quality "A" grade Arabica beans are placed in open-sided, well-ventilated warehouses along the West Coast of India.
From June to September, the beans are piled in thin layers and regularly raked and re-bagged to ensure they are exposed to the humid, moist monsoon winds.
This exposure causes the beans to absorb moisture, swell to almost double their size, and change color from green to a pale gold or yellow.
The beans are carefully monitored and re-bagged frequently to prevent mold growth and ensure uniform moisture absorption.
After 12 to 16 weeks, the beans are sun-dried, sorted, and polished.
Flavor profile
Low acidity: The process strips away the bean's acidity, resulting in a very smooth, mellow cup.
Rich and complex: Monsoon Malabar is known for its full-bodied texture and rich, complex flavor profile with notes that can include spice, caramel, chocolate, and nuts.
Ideal for espresso: The full body and rich crema make it an excellent choice for espresso, particularly for those who enjoy a darker roast style.
The flavor is distinct, often described as earthy and robust, with a unique aroma that some might find different at first.
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Other Methods:
Semi-Washed/Semi-Dry:
This method uses a machine to remove the skin and some of the mucilage, but not all, before drying.
Wet-Hulled (Giling Basah):
A unique Indonesian method where the parchment is removed while the beans are still wet and pliable.
Glossary
Some terms you'll need to know:
Coffee beans grow inside coffee cherries, which have a skin and pulp surrounding the beans.
This removes this outer layer, leaving the beans covered in a sticky mucilage.
This process is often done mechanically using a depulping machine, though hand depulping is also possible.
This is a crucial step in coffee processing, preparing the beans for further treatment like fermentation and drying.
The depulping method (and subsequent processing) can influence the final flavor profile of the coffee.
The depulped beans are typically fermented in water to further break down the mucilage.
After fermentation, the beans are washed and then dried.
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