Sunday, May 14, 2023

Dry or natural method processing of coffee

There are four main methods used to process coffee: Washed Process, Natural (or Dry) Process, Wet hulled and Honey Process.

Dry process is a method of processing coffee beans to remove the fruit of the cherry and dry the bean. In the dry method, the usual objective is to harvest all cherries simultaneously with the least percentage of unripe ones.

The ideal situation is to harvest all fresh, ripe cherries with the least possible damage to the tree, irrespective of the processing system to be used. The cherries are picked ripe, which is important since the fruit itself imparts flavor during this process. They are sorted and weighed before moving to the drying area.

In this method, the coffee cherries are laid out in the sun on a concrete drying patio, or raised beds. Raised beds are preferred because they increase the airflow around the whole fruit to enable more even drying. The coffee is shifted every 30-40 minutes.

Throughout the course of 3-6 weeks, the coffees will ferment, as producers rake these cherries and rotate them to prevent spoiling. During this time, the sugars and mucilage (that sticky substance that coats the seed) will latch onto the seeds, which develop flavors and make them sweeter.

Raking also prevents bruising on the fruit where it’s in contact with the patio or tarp on which it’s resting. Producers are vigilant about avoiding bruising because it can cause flavor defects.

Coffee must be dried from approximately 60% moisture content to 11-12% moisture content. After a period of 3 - 6 weeks, the husk of the dried cherry is removed mechanically. The resulting coffee is often referred to as unwashed. This is the oldest method of processing coffee and is more ecologically friendly, as it does not require water.

Natural sundried, also called “natural process” or “dry process,” means drying coffee cherries whole without the intervention of water or machines to remove any of the fruit. Drying should be uniform to obtain acceptable color, size along with the removal of pests for a longer safe storage. Since coffee production is seasonal, traditional sun drying is quite tough.

This method is widely used in Brazil, but less widely used in Guatemala or Costa Rica where the coffee is more often piled perpendicularly to the old piles.
Dry or natural method processing of coffee

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