The processes
From cherry to bean Three basic processes, endless variations.
Coffee is the pit of a fruit – a cherry! The process refers to extracting the coffee bean from its cherry and drying it, so it can then be roasted and enjoyed. The impact of processing on flavour is significant, and it’s important information to take into account when choosing a coffee. While more and more different processes are emerging, with many variations, we can still distinguish three basic processes – the natural process, the washed process and the honey/pulped natural process.
Photo credit: Crop to cup
Natural process The whole cherry, dried in the sun.
The natural process is the oldest method, requiring the least equipment and water: the cherries are picked and spread out in the sun to dry. A few extra steps can be added before drying, such as fermenting inside the cherry, floating to remove overripe cherries, hand sorting to remove impurities and underdeveloped cherries, and so on. Whatever step is added, the basic principle always stays the same.
When a fruit is exposed to the sun, it ferments and lets flavours develop inside the coffee bean. About 30 days of sun drying are needed for the moisture level to get low enough (around 12%) and for the bean to become stable without turning brittle. The natural process may seem fairly simple at first glance, but it can easily take a turn for the worse. That’s why it has to be carried out with great care, so the result is high quality, with beans drying evenly and without mould.
- A less pronounced acidity
- A creamier body
- Sometimes fermentation aromas.
Washed process Pulp, ferment, wash.
In this method, the coffee cherry is removed using a machine called a pulper, which slides the coffee bean out of its cherry pulp. However, the pulper doesn’t remove all the layers around the coffee bean.
Three layers remain around the bean: the mucilage, the parchment and the bean’s skin (silverskin). The mucilage, a layer of pectin coating the coffee beans, can be effectively removed through fermentation. The beans therefore spend several hours fermenting, and that’s where it can get complex: dry fermentation, in water, anaerobic (without air), long, short... the combinations are endless, and this step is crucial work for producers, who can use this fermentation to bring out certain elements in their beans.
After fermentation, with the pectin layer now partly broken down, the coffee is washed with clean water to remove the residue and prepare it for drying. That’s when the coffee beans, still wrapped in their parchment, are spread out in the sun to dry. Drying washed beans takes close to two weeks to complete.
- Cleaner, more delicate flavours
- A brighter acidity.
Photo credit: Semilla coffee
Honey or pulped natural The sugar in the mucilage, caramelizing.
Pulped natural and honey are two terms for the same process, adopted for different reasons in different countries. In this process, the cherry is pulped right from the start, as in the washed process. However, instead of removing the mucilage through fermentation and washing, the coffee is left in the sun to dry with its mucilage still on.
Why call it honey? The reason is simple: the mucilage coating the coffee is mainly made of sugar, giving it a texture similar to honey. The sugars in the mucilage caramelize around the coffee bean as it dries.
There are different degrees of honey, generally identified by a colour: white, yellow, red and black. The degree of honey is influenced not only by how much mucilage is left on the bean, but also by the total drying time. The darker the colour, the more mucilage there is and the longer the drying.
- Tends to offer the rounder body of a natural while keeping the delicacy of a washed
- Closer to the characteristics of a washed for a white honey, or those of a natural for a black honey.
Hulling The last step before export.
One crucial step remains before export, even after the beans have been dried and stabilized: hulling. Natural coffee is still inside its dried cherry, honey coffee in its mucilage, and washed coffee in its parchment — all of which have to be removed before roasting.
Hulling is done with a machine, through which the coffee beans pass several times, removing these extra layers. At this stage, the beans are also sorted by size and density, ensuring greater uniformity.
After hulling, only the skin (silverskin) is left on the beans, but that layer won’t come off until roasting. It detaches naturally as the beans roast and is drawn out of the roaster. The silverskin helps keep the beans fresh for a longer period.
Processing is only one of the many factors influencing the flavour of coffee beans. Still, recognizing its impact on taste can help you make informed choices when buying coffee — while appreciating all the meticulous work behind this beverage.