What is coffee processing?

What is coffee processing?

Most of the coffee grown on the planet is processed and prepared for export in one of two different processes, or some variation of those two. As coffee starts its journey towards our cup as a small cherry, the first thing that needs to happen in the transformation is to deal with the thick skin of that cherry.

In the “european” method, or “washed” coffee method, the skin is removed to begin the process. This typically happens with a depulper (of which there are many models).

In many countries coffee is still depulped with a hand pulper which is essentially a manual machine which removes the skin of the coffee as it passes through two drums.

As operations become more sophisticated, the use of electrical depulpers come into play. These can range from disc depulpers to micro mills to large industrial machines at very large mills.

Once the skin is removed from the cherry, we then have to deal with the mucilage (a sticky fruity substance which surrounds the seed of the cherry which is what we ultimately roast.

From this point, the seeds are either soaked in water (fermentation process) in order to loosen the mucilage and remove it from the seed, resulting in a washed coffee.

Traditionally the seeds are then laid out on large patios to dry. This coffee is turned frequently to avoid it spoiling.

Much of the coffee that Transcend now buys is laid onto drying tables to dry. This method results in better quality as the coffee dries more consistently and dries from both the top and the bottom at the same time. The protective sheath around the seed is called parchment, and parchment coffee is typically rested for two to three months before it is prepared for export.

More recently producers have been leaving various degrees of mucilage on the seed and letting the coffee seed dry that way. This is what we now know as honey coffee. The sweet mucilage will have an impact on the ultimate flavour of the coffee as the sugars and acids of the mucilage effect the seed during the drying process.

Another method for preparing coffee is the “natural” method where the coffee seed is allowed to dry with the skin of the cherry and the mucilage intact.

This process was typically used in countries where there was little access to water. Some of the most notable examples of this method is Ethiopia where regions like Harrar are renowned for producing flavours of strawberry, blueberry, etc. as a result of the drying process.

In situations like this, the cherry is laid out on drying tables, or sometimes the ground, and allowed to dry until hard. Then at a dry mill, the hardened fruit is broken off of the seed with another piece of equipment.

-Poul Mark 

Transcend's Founder

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