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How specialty coffee is processed

Coffee needs to be processed after it is picked from the tree and a great deal of effort, technology and science goes into creating coffee flavour profiles for the specialty coffee industry. In this article we want to provide an overview of the four common processing styles we regularly see in specialty coffee.

Please note, that passionate producers (the farmers) who seek to continually improve quality, fastidious roasters (us) and conscientious consumers (you) who seek new experiences, together inspire ongoing innovation and development of new processes which can only take us to new and wonderful places.

Before we overview the four main processing methods, it’s helpful to check out the cross-section of a coffee cherry as follows.

Coffee Cherry Profile

Natural process

In the natural process, the coffee cherry is picked and the entire cherry is allowed to dry on the seed or bean. Generally this drying will occur on raised beds, but in countries like Brazil, they have a great deal of land and so they commonly use large flat outdoor patios.

The remaining cherry is then removed. Generally the coffee is left to mature in it’s parchment. After 1-3 months, the coffee is then dry milled to remove parchment, sorted again, graded for sale, cupped and sold to roasters.

Cup flavour: Rich cocoa, heavy syrup, fruit notes leading to fermented flavours.

Washed process

In this method the coffee cherry is picked then pulped. This is where the skin and fruit layer is removed, which is then commonly used for cascara.

The mucilage is left on the parchment, and then the coffee is inserted into large vats of water called fermentation tanks. The time varies as per farmers direction with the coffee, generally 48 hours.

After fermentation is complete, a further washing is conducted on the coffee to further clean up the bean and remove any remaining mucilage. The coffee bean is then prepared for drying. In dry countries or areas, wet or washed processing is seldom seen because of the lack of running water.

The coffee is then matured in parchment for 1-3 months. At this point it is dry milled to remove parchment, sorted, graded, cupped, scored, bagged and sold.

Cup flavour: Mild body, clean and transparent flavours more clarity, hence nuance is easily perceived.

Pulped natural process

In the pulped natural process both the skin layer and fruit layer is removed. The mucilage is left on the parchment which is then left to dry on raised air beds.

Farmers vary the drying time and we see this manifested in the various processes. The coffee is then washed vigorously to remove and remaining fruit.

Cup flavour: The growers are trying to balance the cup profile, and thus aiming to lower the presence of heavy cocoa’s and nuts from a full natural style and improving the complexity of washed coffees.

Honey process

The honey process is a modern style, where just the skin is removed from the cherry. Therefore, this is the process that leaves most fruit on the coffee, more than the pulped natural process.

Farmers often cover the coffee with heavy plastic and then left to dry on raised beds. Sometimes a hot air machine is used to force drying under the tables. This process accentuates fermentation but also gives the farmer more control over cup profile and taste..

The cup flavour:

  • White honey – Almost fully washed, with a fraction of ferment concentration.
  • Yellow, Orange and Red honey – Somewhere in between.
  • Black honey – Almost fully natural with a touch more elegance, restraint and complexity than a full natural.

 

We have also recently purchased coffee that has gone through a black winey process.

Black winey process

The ripe red cherry is picked then the farmer places the coffee into a polystyrene bag in approximately 40kg lots. The coffee is then left to become black and develop a winey character. The coffee is then put on raised beds and allowed to dry to 11% moisture.

The coffee is rested to allow the enzymes to settle down and balance, which takes about four weeks. At this point the coffee is dry milled, cupped, scored, bagged and sold.

The cup flavour: Well balanced ferment and low acidity for a coffee of this style, exceptional enhanced sweetness

How far does the rabbit hole go?

You will see interesting things such as growers adding yeast to fermentation tanks to add flavour to the cup and some farmers in regions such as Mexico are starting to do special lots of coffee aged in Mezcal, Tequila and rum barrels for interesting cup profiles.

The future looks interesting and flavoursome.  

Thanks for reading, hope it has been interesting!

Dom

Dom T

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