THE PROCESS IN MOTION

How is mucilage removed mechanically?

Start the scene or choose a stage. The animation simplifies the mechanism; what follows gives the details and the available references.

▶ Play the process01Pulp dry, within six hours02In the column, the bean rises and the water descends03The honey comes out whole, the bean comes out clean04Adjust every week, or tear the parchment

Pulp dry, within six hours

The pulper pinches the ripe cherry and separates skin and pulp, 43.6% of the fruit, without water. A grate with 7 to 8 mm bars, the zaranda, rejects the unpulped fruit. The beans come out covered in mucilage, 14.9% of the fruit: a sweet flesh in gel form, stuck to the parchment.

Read the stages without animation

1. Pulp dry, within six hoursThe pulper pinches the ripe cherry and separates skin and pulp, 43.6% of the fruit, without water. A grate with 7 to 8 mm bars, the zaranda, rejects the unpulped fruit. The beans come out covered in mucilage, 14.9% of the fruit: a sweet flesh in gel form, stuck to the parchment.
2. In the column, the bean rises and the water descendsAn auger pushes the beans to the bottom of a column where a ribbed rotor turns. Mucilage is pseudoplastic: the more it is sheared, the more fluid it becomes. Shearing and bean-against-bean impacts detach the gel in a few seconds. A little water enters from the top, counter-current: the bottom of the column detaches, the top rinses.
3. The honey comes out whole, the bean comes out cleanNothing has fermented: the pectin leaves the bean as it is, in the form of concentrated honey, and goes with the water to the pulp screw and then to the compost. The clean parchment coffee goes straight to the dryer, down to 10 to 12% moisture, and is never submerged while waiting.
4. Adjust every week, or tear the parchmentAdjustment is made by coffee flow rate, stopwatch in hand, and checked every week because the size of the fruit drifts. Too aggressive, and the rotor tears the parchment and damages the bean. Two other losses do not come from the machine: green cherries, with 30% of cups rejected from just 2.5% of the lot, and waiting under water before drying.

To remember: The mechanical demucilager waits for nothing and degrades nothing: it tears off the mucilage by friction, in a few seconds and with very little water. It comes after the pulper and does not remove the parchment.

In history: Cenicafé developed BECOLSUB and then Ecomill; the first settings also fed criticism about quality.

Read the full article and its sources ↓

The principle replaces fermentation with friction: the coffee in parchment passes through a machine that tears off the mucilage by abrasion, with very little water. In the 1980s and 1990s Cenicafé developed the BECOLSUB set and then the Ecomill: about 90% less pollutant load in the discharged water, and a saving of the order of 35,000 liters of water per 1,000 kilos of coffee processed.

A private manufacturer announces 0.2 liter of water per kilo of cherry and 95% of the mucilage removed, a figure from a product page. The forgotten lesson: the first machines, designed first for canephora, damaged the bean; poorly adjusted friction wounded parchment and seed, and the wounds produced parasitic fermented flavors. A technology made for cleanliness dragged along for twenty years a reputation for degrading the cup, judged on its first implementations.

Cenicafé, BECOLSUB and Ecomill (institute, solid level); Penagos, manufacturer page (low level); LC ch. 17b