What Are The Different Coffee Processing Methods?

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How do the different coffee processing methods affect our coffee? This topic rarely makes it into industry headlines or coffee shop discussions, however, it is an essential part of crafting the flavours and characteristics of our cup of coffee.

What do we mean by coffee processing? Well coffee processing is the removal of the various layers of the coffee fruit. 

  • The outer skin or pulp. 
  • The mucilage - A sticky layer that is responsible for much of the coffee’s sweetness.
  • The parchment - A papery layer. 
  • The silver skin - A membrane which covers the two seeds.

Now let’s dive in and learn more about the wonderful world of coffee processing methods.

Natural Processing

The natural processing, also known as dry process is a back-to-basics approach that stems from Ethiopia, where coffee cherries are placed on raised drying beds to slowly dry in the sun, allowing the coffee seeds to absorb fruit flavors and sugars from skin and mucilage. 

For this process, the fruit is left on the bean, and there’s little disruption to the coffee while it dries. Once sufficiently dried the fruit and parchment are removed at a dry mill. 

This method is used in dry environments where there is no access to water, mainly Ethiopia and Brazil, additionally, the natural coffee is one of the most eco-friendly methods compared to other coffee processing techniques.

This process definitely adds flavours such as fruitiness and sweetness to the coffee, regardless of the variety and region. The most common flavour notes found in natural processing coffees are: Tropical fruits, honey and berries.

 

Our Sippy pick for this processing method is:

Washed Processing

The washed processing, also known as wet processing method, is one of the most commonly used processing methods within the coffee industry. During this process  all of the skin of the fruit  is removed mechanically from the coffee bean before the beans are dried. 

The removal of the fruit skin is done with a machine called depulper. After depulping the beans are put into a water tank where the fermentation process will remove the remainder of the fruit skin. The amount of time that the fermentation requires depends on the climate and altitude. Usually the fermentation requires 24-72 hours and if the coffee beans are fermented for too long, it will have a negative impact on the flavour of the cup. 

After the fermentation is done, the coffee beans are washed to remove any leftover skin and then it is ready to be dried. Drying in the washed process is done in brick patios or raised beds. The beans can be also mechanically dried, especially in regions where there is not enough excess humidity or sunshine.

The washed process leads to bright and acidic flavors in the cup. Many farmers choose the washed process over other processing methods as it can lower the risk of irregularities, making it a more stable way to process coffee. 

This process can truly highlight the character of a single origin bean like no other process, it is the reason why so many specialty coffees are washed.

Our Sippy pick for this processing method is:

 

 Honey Processing

The honey processing method has been mainly known to be used in Central American countries such as Costa Rica and El Salvador. During this process the cherries are mechanically depulped but to leave the exact amount of skin on the beans.

After depulping the beans go straight to the drying tables or patios to dry. As there is less skin surrounding the beans, the risk of over-fermentation is lower than in the natural process but the overall sweetness and body in the cup are increased by the sugars in the remaining skin. 

The name Honey comes from the coffee cherry skin being sticky. There are actually different types of honey processed coffees: white, yellow, red, golden and black, with black being the one that has been left to dry the longest.

Honey processed coffee, when executed correctly it can have positive attributes from washed and natural coffees, acquiring both, the brightness from a washed method and the sweetness from a natural method.

Our Sippy pick for this processing method is:

 

Anaerobic Processing

The anaerobic processing method, anaerobic meaning oxygen free, is one of the most recent modern processing methods, it has gained popularity due to being used increasingly more during coffee competition. 

During this process, similarly to the washed method, there is fermentation involved, however, this time the fermentation takes place in tanks that have been sealed for no oxygen to get in contact with the coffee. This process allows for a high level of control of the sugars, temperature, pressure, pH and even time. 

The fermentation process can last up to 23 hours, it all depends on if the mucilage has been inside long enough to be consumed but not so long that it would be turned into alcohol. 

Lastly, one the fermentation process has been finalised the coffee is the dried for 4 hours in the sun to avoid fermentation to carry on and alter the flavours already achieved.

Even though this new method is very experimental it can lead to complex and unexpected flavours in a cup that can positively surprise your taste buds.

Our Sippy pick for this processing method is:

Wet-hulled Processing

The wet-hulled processing method is predominantly used in Indonesia, however, this method is also used in other very humid environments. 

Wet-hulled tends to get confused with wet-processed or washed coffee, however, these two processes have completely different end results in a cup. Wet-processing highlights delicate acidity and sweetness, on the other hand, wet-hulling highlights body, earthy flavours and mutes acidity.

During this process the goal is to remove the parchment skin from the coffee bean. Hulling away the parchment is optional as sometimes coffee beans are sold in parchment

After coffee beans have been dried, either in the sun or in drying machines, similarly to other methods,  the parchment skin is crumbly and dry, so it can be easily removed. In the case of wet process coffee, hulling removes the dried husk surrounding the coffee bean. 

Regardless of how many layers are being removed during hulling, it is all taken care of in one step by a machine called a huller. Hullers range from high-end machines to simple millstones that tap away at the coffee to remove the hulls.

The fast pace of the wet-hulling process is necessary in countries such as Indonesia due to the rainy climate and high humidity making it challenging for farmers to dry coffee consistently for extended periods. 

 

Our Sippy pick for this processing method is:

 

Pulped Processing

Pulped Natural processing is a method that removes the outer skin of the coffee cherry to expose the fruity layer, and is then allowed to dry in the sun or sometimes, with mechanical dryers. It is considered to be a mix between wet  processing and dry processing, however, it needs more water and time compared to the straight natural processing, but offers a better quality cup highlighting  the natural sweetness and aromatics of coffee

Often used in Brazil where strip-picking is the norm, the pulped natural processing method involves first pulping the coffee to remove the outer skin, though this is done without the fermentation stage. The coffee cherry is then sun-dried, with much of the mucilage still attached, on a raised drying bed or on a patio.

This processing method is suitable for countries with low humidity, as coffee covered in mucilage needs to dry quickly to avoid fermentation.

Our Sippy pick for this processing method is:

We hope that this made you understand a little bit better the wonderful world of coffee processing methods and that now you are more inclined to trying different methods for your daily dose of caffeine!

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