How to process great Coffee

In depth article about everything needed to produce high quality coffee, from picking to roasting by Maarten Hol

Hello Friends,

This article is about how coffee is processed. From the fruit until the roasted coffee. We will go step by step through the whole process, eventually ending with roasting coffee beans as available in our online store.

Picking

First the coffee is picked. To produce a high quality coffee only the ripe coffee fruit are be picked. This ensures the highest sugar contents and most rich and complex flavor.

Red Coffee Cherries being picked – Photo courtesy of Bryon Lippincott for Yunnan Coffee Traders

It takes about eight months to produce the coffee fruit (often called cherry) after blossoming. When the fruit is ripe, picking begins. In Yunnan, China that is November-December. In order to make sure the coffee tastes best there is a small window in which the fruit of the coffee is optimally ripe. If the fruit is unripe, the taste of the coffee will be sour and astringent, while overripe fruit get moldy and smelly.
Picking at our farms in done by hand. Only ripe cherries are picked. After picking the cherries go into a color sorter to take out any accidentally picked unripe or overripe cherries.
Picking is done several times, because not all cherries are ripe at the same time. Picking is one of the most labor intensive jobs on the coffee farms. All our work is done by legal employment and people are paid fair wages so they have proper income for their families.

Farm process

Next the coffee cherries needs to be processed so that the outer layers of skin (7), pulp (6), mucilage (5) and parchment (4) are removed and the green coffee bean (2) remains. The silverskin (3) is removed during roasting. There are two main methods and a hybrid to do this: water process, natural process and honey process.

Coffee Bean exploded view – image adapted from Wikicommons
Washed coffee

The first of the three processes that removes the outer layers of the coffee cherries to produce coffee beans is the wet process.

Freshly picked coffee in fed by conveyor belt to the color sorter and wet mill for processing – photo courtesy of Bryon Lippincott for Yunnan Coffee Traders

In the wet process (sometimes called washed coffee) the fruit is first mixed with water to remove floaters (good coffee fruit sinks). Then it is fed through the wet mill, a machine that mechanically removes the skin and some of the mucilage from the coffee bean.
After this step the coffee is left in water for about a day to ferment. This causes the rest of the mucilage to change texture so it can be washed off.
After washing, the coffee is spread out on cement slabs to sundry for about three weeks. During this time the coffee is turned daily to prevent mold from forming.
When the coffee has a moisture contents of about 10-12% the coffee is packed and shipped to the dry mill, where the final steps of processing are performed.
Washed coffee is extremely suitable for large volume continuous production and it results in very stable coffee between the different pickings. One of the downsides is the amount of water needed for this process.

Natural coffee

The second of the three coffee process methods is the natural process.

Whole coffee cherries being dried on concrete slab for natural processing – photo courtesy of Bryon Lippincott for Yunnan Coffee Traders

In this process (sometimes called dry processed coffee) the fruit is first mixed with water to remove floaters (good coffee fruit sinks) and cleaned. Then it is manually sorted: only perfectly ripe cherries can be used, anything damaged, overripe or otherwise sub-standard is removed. Also twigs, leaves, stones and other foreign matter is removed.
On some farms the coffee cherries are first fermented for a couple of days in barrels or plastic sacks. This alters the flavor to more winy/yeasty notes. Some estates even ferment twice.
The whole cherries are then dried on concrete slabs or on raised beds. Coffee is constantly turned to ensure even drying and to prevent mildew from forming. This is the most important step in the natural process.
When the cherry has a moisture contents of about 10-12% the coffee is packed and shipped to the dry mill, where the final steps of processing are performed.
Natural coffee is extremely suitable for small lot specialty coffee. Flavor notes are often unique to the soil and specific drying process. Down side of this method is it’s sensitivity. One mistake in the drying phase and a whole lot can be ruined having a major impact on the business.

Our Fuyan Natural is processed in this way and available in our online store Menglian Fuyan Specialty Natural 1lb.

Semi-washed coffee

Semi-washed coffee is a bit in between washed and natural, sometimes referred to as honey process.

Skin removal of picked coffee cherries for honey-processing – photo courtesy of Bryon Lippincott for Yunnan Coffee Traders

As with washed coffee, first the floaters are separated. Then the outer peel of the coffee fruit is mechanically removed. But, like natural coffee, semi-washed coffee is not fermented to remove the mucilage, but is sun-dried straight after peeling.
During the drying phase the coffee will naturally ferment, just like natural coffee, but not as strongly. Resulting flavors are often very delicate. As with all sun drying processes, the coffee is turned often to prevent mold from forming and ensuring an evenly dried coffee.

Dry mill

The final process before coffee roasting is called hulling. Which is the removal of the hard outer layers so that only the coffee bean in its silver skin remains.

Parchment coffee

Both natural and washed coffees are dried. Dried natural coffee looks a bit like raisins and dried washed coffee is shown in the picture and referred to as parchment coffee.
Hulling is done very similarly to rice, and using very similar equipment. This step is usually combined with sorting the coffee in different grades (these are regionally dependent and usually based on the size and sometimes the density of the beans). Also foreign material like pieces of concrete from drying, or twigs and little stones are removed.
When the outer layers are removed and the beans are sorted, they are packed in air tight bags and can be stored for about a year.
Coffee is finally ready for roasting!

Roasting

The final process is roasting. The basic process involves heating the green coffee in a machine in order to change it physically. The result is dependent on the roasting time, speed of temperature increase and final temperature.

Roasted Coffee in the cooling tray

Light roasted coffee has bright characteristics: higher acidity, fruitiness and a general lightness to the taste.
Medium roasted coffee is balanced between acidity and bitterness and often has a distinct sweetness to it.
Dark roasted coffee is often bitter and strong in flavor. It generally has a nostalgic feel to it.
Blending of different coffees is done pre or post roast in order to ‘design’ a certain coffee taste.
The roast master has to decide the roasting technique based on the origin and naturally occurring flavors in the coffee. A heavy body naturally balanced coffee can be roasted darker to emphasize the boldness of the coffee, while a honey processed coffee with citrus notes has to be roasted lighter in order to keep it’s delicate nature.

Our Fuyan Natural coffee is roasted slowly to a medium color. Because natural coffee is quite delicate it cannot take a very quick heat increase well. The resulting roasted beans are balanced and fragrant with notes of strawberry and cream. Available in our online store: Menglian Fuyan Specialty Natural 1lb.

Enjoy your Coffee!

Maarten Hol

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