What is demucilage in coffee processing?
Demucilage, also called demucilaging, is the partial or complete removal of the sticky mucilage layer surrounding parchment coffee after depulping. This can be achieved through fermentation followed by washing, or mechanically using a demucilaging machine. The parchment layer remains intact around the coffee seed.
What is coffee mucilage?
Mucilage is the sticky, pectin-rich fruit layer that remains on the parchment after the cherry’s outer skin and pulp have been removed. It contains water, sugars and other compounds that provide nutrients for microorganisms during fermentation. How much mucilage is removed before drying helps distinguish washed and honey processing.
How is mucilage removed from coffee?
Fermentation and washing
After depulping, coffee can be fermented to break down the mucilage, making it easier to wash away. Fermentation may take place with or without added water. The coffee is then washed to remove the loosened material before drying in its parchment layer.
Mechanical demucilaging
Mechanical demucilagers use friction and controlled amounts of water to remove mucilage from the parchment. Producers can adjust the equipment to remove different amounts, depending on the intended processing method. Mechanical removal does not rely on a fermentation stage to break down the mucilage.
Demucilage in washed and honey processing
Washed coffee: Mucilage is removed before drying, either through fermentation and washing or mechanical demucilaging. The coffee is dried with its protective parchment layer still attached.
Honey coffee: Some or all of the mucilage is deliberately retained during drying. Partial mechanical demucilaging allows producers to control how much of this fruit layer remains on the parchment.
What is the difference between depulping and demucilaging?
Depulping removes the coffee cherry’s outer skin and fleshy pulp. Demucilaging removes the sticky layer that remains on the parchment afterwards. Although some equipment combines these operations, they refer to the removal of different fruit layers.
FAQ about demucilage
Q1: Is demucilage the same as fermentation?
No. Demucilage describes the removal of mucilage. Fermentation is one way to break it down so it can be washed away, but machines can also remove it mechanically.
Q2: Does demucilaging remove the parchment?
No. Demucilaging removes the mucilage coating the parchment, not the parchment itself. The coffee seed remains enclosed in this protective layer during drying.
Q3: Is all the mucilage always removed?
No. The amount removed depends on the intended process. Washed processing removes mucilage before drying, while honey processing retains some or all of it.
Q4: Can coffee be washed without fermentation?
Yes. Mechanical demucilaging can remove mucilage without relying on fermentation to break it down, providing an alternative approach to washed processing.
Q5: Does mucilage determine the coffee’s flavour?
Mucilage plays a role in fermentation and drying, but it does not produce one predictable flavour profile. Fermentation conditions, drying practices and producer decisions also influence the result.