Wet vs. Dry Processed Coffee
Wet Processing
All of the coffee roasted by Steaming Bean is processed using the 'Wet' method,
which produces beans of higher quality than any other method. This process
really begins at harvest and ends with the green bean in its parchment, ready
to be dried. It is essential that the coffee berries are allowed to ripen on
the vine, and then, when at their peak of ripeness, handpicked, leaving any
unripe berries behind. Uniformity in berry size is also important as removal of
the pulp around the coffee bean uses a machine calibrated to size and any
smaller beans would escape having their pulp removed. After the berries have
had the pulp removed, they must go through a process of washing and sieving to
remove any remaining pulp and skin.
At this point, all that remains surrounding the two beans is parchment and
mucilage. If the mucilage is not removed, it can cause the beans to ferment.
Whereas a certain amount of fermentation is desirable, too much can have a
negative effect on the bean. While insoluble in water, slight fermentation
causes the mucilage to dissolve. To that end, the beans are put into tanks,
which are approximately 3 feet deep with cement walls. Sometimes water is added
to the tanks, but often the moisture in the mucilage itself is used to promote
the slight fermentation necessary to remove the mucilage from around the
parchment covered beans. This process can take anywhere from 6 to 80 hours
depending on the climate and composition of the mucilage itself and the tanks
must be stirred often. Once the mucilage has dissolved, it is removed
completely through thorough and repeated washings. The beans are ready now for
the next stage, which is drying.
Dry Processing
Dry processing is a much simpler, more natural method, of processing, but
produces a less desirable bean. Essentially, the coffee berries are strip
picked from the branches, paying little attention to ripeness, and dried in the
sun in their skin, pulp, and mucilage. After about 20 days, the berries are dry
and resemble dark nuts. They are then shipped quite often to cooperatives,
where decorticating machines free the beans from their skin, pulp, and mucilage
(Due to the cost of the equipment needed for this stage, very few growers can
perform this function on their own). Unfortunately, this method allows many
'imperfect' beans to slip through during processing and relies heavily on bean
sorting at the very end. By the time the beans processed via the wet method
reach this final sorting stage (they are sorted several times throughout the
process), very few undesirable beans have been retained. Sorting, and strip
picking are two of the factors which can compromise the quality of coffee
processed using the dry method.
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