Picking, Wet Milling and Sun Drying

The coffee plants start to produce flowers two to three years after they have been planted and from these flowers come the coffee cherries. Sometimes it might take up to five years from the first bloom for these cherries to mature into a high quality coffee. Each year the cherries take about six to eight months on the tree to ripen. Red berries contain higher levels of aromatic oil and lower levels of organic acid making them more fragrant, smooth and mellow. Where as green or unripe berries are characterized by bitter/astringent flavor and a sharp odor.

In most countries, the coffee crop is picked by hand, making it a labor-intensive process that lasts many weeks. However this means that pickers can literally cherry-pick only those cherries at the peak of ripeness, which will go on to make higher quality green coffees with greater consistency. Although any observer at most coffee farms or wet mills might witness organized chaos at this time of year it, clearly coffee picking is one of the most pivotal stages in coffee production.

Pedro picking ripe coffee cherries
Carrying Quintales of Coffee

The coffee cherries are processed the day after they are picked ready for fermentation. Any delay and the juices in the berries can over-ferment. There are several methods of processing coffee, such as ‘pulp, ‘pulp natural’, and ‘honey’, however almost all coffee in Central America, including the coffee from our farms, goes through the ‘wet process’, sometimes referred to as ‘fully washed’. In the ‘wet process’, cherries are first sorted by being immersed in water, where the ripe cherries sink while any remaining unripe cherries float and are skimmed from the top.

The cherries that sink go through a pulper, which takes away the outer skin – also called pulp, which in many cases is used as an organic fertilizer. What remains of the cherry is placed in fermentation tanks and soaked in water to loosen the sweet honey-like substance that encases the inner bean, known as the mucilage. During this process, a controlled fermentation of sugars contained within the mucilage takes place, affecting the flavor of the bean. This process usually takes between 24-36 hours, before washing this gooey substance away with water.

Coffee in the fermentation tank at the wet mill
Coffee in fermentation tank - close up

The fermentation process must be carefully monitored for the mucilage to be completely removed, while ensuring that the coffee does not acquire undesirable flavors. Jose, the wet mill manager at Finca El Hato, who has refined this process for the past thirty years, knows exactly when to cease fermentation just by the feel of the beans. Many Central American wet mills have such characters who rely, on instinct and experience over scientific measurement and without whom the coffee would not taste the same. For institutions like Jose, machinery will never replace good old-fashioned intuition.

Having been thoroughly washed, the coffee is dried to about 10-12% moisture content. The drying normally takes place on large cement patios where coffee is spread out in rows and moved every four to six hours to ensure even dying. The Patio drying can take up to 8 days. In some farms and on some occasions where the weather does not permit this, the coffees can also be partly machine dried.

Coffee being turned over in the patio
Straight rows of coffee beans drying