Wet Process


Wet Mill

The wet mill is very important, as it is where we obtain the best quality coffee beans, free of floats, over-ripe and under-ripe coffee beans.

During harvesting of the coffee cherries (coffee beans still on the tree), harvesters (cortadores) must be selective and only cut off the ripe cherries. In order to avoid fermentation and damage to the quality of the coffee, the cherries must be taken to the mill to be processed as fast as possible.

Eco-Delight Coffee pays careful attention to ensure a wet process that is ecological. To be ecological the wet process must fulfill certain characteristics.  The removal and transport of pulp (cherry peel) must be essentially non-hydraulic. The very small amount of water used is sent through a hydrodynamic solids filter, and re-circulated. An appropriate clean water consumption does not have to be greater than 1 gallon for each 27.5 pounds of coffee cherries.

As seen in the photo to the right, the process begins by depositing the coffee in a hopper where gravity feeds it to a de-stoner channel. Water is added to the system and re-circulated. The de-stoner channel is very important because it retains stones or objects that can damage machines and is unwanted in the coffee.  Note that the system shown here is adapted to the environment, rather than adapting the environment to the process - ecological.

At the end of the de-stoner channel, the coffee falls into a basin and from there is pumped to a siphon.  The siphon separates the good (heavy) coffee from the floats (poor quality coffee).

After separating out the floats, the water is removed by use of a "de-water" transporter that feeds the beans to a machine called a green coffee separator.  This separates unripe and overripe beans from the ripe ones.  Floats, unripe and over-ripe bean are used by non-specialty coffee distributors that are not as selective about their coffee, paying low prices for low quality. In many cases these low cost poor quality beans are used in instant coffees, or by some high volume coffee suppliers.
Ripe beans are fed to a de-pulper (seen below), which removes the pulp.  What remains is called wet parchment and mucilage.  Mucilage is a gelatinous high sugar content coating around an inner shell, called parchment, which surrounds an inner two-segment seed.

The next step is removing the mucilage with a machine called a demucilager. A less ecologically friendly method of removal is fermentation in a battery of tanks.  Fermentation uses more water and takes longer.  Mucilage is taken to a treatment plant and although it cannot be recirculated like water, it is added to the pulp to make compost for use in the coffee plantations.


Now he coffee is clean parchment with 54% of humidity, and is ready for drying.

Here we are!