How we have written in blog, more heree. There three main coffee processing methods:
- Wet / Washed
- Dry / Natural
- Honey
There are more, less popular coffee processing methods.
Double- pass natural technique
Natural, tree-dried, overripe coffee cherries are being used for this processing method. The harvested cherries are soaked for 12 – 24 hours to soften the skin and pulped. Then they are processed via the wet processing method. Overripe cherries tend to create forest berry flavour tones and enhance the sweetness of the final cup of coffee.[1]
Wet-hulled
This is a traditional method used in Indonesia, especially in Sumatra. The farmers remove the outer skin of the cherries. The beans, which are still covered with the mucilage (fruit layer), are then placed for one day in fermentation tanks to break down the mucilage. The beans are then covered only by the wet, papery parchment skin underneath the fruit layer that protects the green bean. The parchment is being removed in the middle of the drying process. After the parchment removal the beans are dried to 12% to 13%.[2]
Via other processing methods the green bean is being dried inside the parchment skin until it has reached a moisture content of 10-13%. The parchment layer is removed much earlier during the wet-hulled process.
Wet-hulled coffee typically has a low acidity, heavy body and earthy flavor profile.
Washed Carbonic Maceration
The Carbonic Maceration technique is typically associated with natural wine making.
It’s now being used as a unique, innovative coffee processing method. The goal of this methods is to enhance the sweetness and clarity of the fruit notes.[3]
The cherries are being harvested and washed. Then the whole fruits are being fermented in sealed stainless steel containers which get carbon dioxide pumped in to remove the oxygen from the container. During this process the temperature and humidity are carefully monitored. After the fermentation, the residue of the fruits is being removed and the beans are dried.
Kenyan process – Double fermentation (Double washed)
This processing technique is a variation of the washed processing method. To create a more complex flavour profile, the beans are de-pulped, mucilage coated seeds are soaked in the fermentation tank for a second time.
Anaerobic process – Oxygen-free fermentation
Once the coffee is de-pulled and separated from their mucilage. There are added to tanks, after the cover them with own mucilage and close for 24hrs. The flavours of the juicy mucilage under the pressure of mucilage liquid goes into the coffee parchment.
A geographical overview of coffee processing methods
I had a discussion with a Barista in a
coffee shop. He was saying to me that Honey processed coffee beans are only
cultivated in Central America. I researched the topic. This Barista was wrong.
Here is what I found:
[1] Sweet Maria’s, New(ish) Methods in Brazil Coffee Production: https://bit.ly/2SDP8LE
[2] Peacock Coffee & Tea Traders: https://bit.ly/2TFMtOH, and: Kelleigh Stewart, What is Giling Basah? Paradise COFFEE ROASTERS, October 13, 2016: https://bit.ly/2RUW9TK
[3] The Modern Approach to Coffee Fermentation, Artisan: Asser B. Christensen, WASHED, NATURALS AND HONEYS, THE ULTIMATE GUIDE TO COFFEE PROCESSING, February 5, 2018: https://bit.ly/2BsUeke