Discovery Subscription (2020, 12) - The Natural Process - English


The Natural Process

  • This month we’re focussing on a specific post-harvest process, but applied in very different ways on very different raw material.

  • The natural process is the original method of processing coffee, but is now associated with lower quality lots, especially in East Africa.

  • Recently, quality-focussed producers have retaken ownership of the process, drying coffees with great care in order to create clean and transparent naturals.

  • The natural process often adds richness and soft fruit driven by the fermentation.

  • Francisco Mena has produced a naturally-processed Caturra at Sumava de Lourdes in the West Valley region of Costa Rica.

  • The smallholder farmers of the Kercha Woreda delivered their cherry to the Hasen Sormolo mill in Guji, where they were also processed using the natural method.

1 x coffee

Sumava, Costa Rica 
(250g / 5.3oz)

2 x coffee

Guji Kercha, Ethiopia
(250g / 5.3oz)

Sumava, Costa Rica
(250g / 5.3oz)

First coffee - Costa Rica

Shade-dried Natural Caturra

Strawberry, Milk Chocolate and Brown Sugar
(250g / 8.8oz)

This is the third time we have purchased coffee from the Sumava de Lourdes micro-mill in the West Valley of Costa Rica. The mill is located just outside the town of Naranjo de Lourdes, and the two farms that serve it, Monte Llano Bonito and Monte Lourdes, sit between 1600 and 1800 metres above sea level. This mill is owned by Francisco Mena, who also co-founded Exclusive Coffees, our export partner in Costa Rica. Francisco is very well-known in Costa Rican coffee circles, having been one of the driving forces behind the country’s ‘micro-mill revolution’, empowering smallholder producers to take control of the types and quality of coffee they produce. After founding Exclusive in 2008, Francisco set about developing microlots with these producers, based on the needs of the expanding specialty coffee market. He also continues to work tirelessly to connect these producers with buyers like us who are willing to pay a premium for their expertise and the quality of the coffee they produce.

First coffee - Sumava

Planting thousands of trees

As if that wasn’t enough to keep him occupied, Francisco decided to distill all of the knowledge he had gained from working with these talented producers into his own project, and in November 2014, he took control of the Sumava de Lourdes micro-mill and its two attached farms. With help from a Czech investor, he took over the farm, which had not been cared for properly in many years. The investor brought the name, Sumava is a national park that straddles the border between Czechia, Austria and Germany. Francisco is a big proponent of young plant tissue and of new varietals, so he set about planting many thousands of trees, and repairing the soils. Francisco and his team took many soil readings to determine what was lacking, before using mountain micro-organisms to create organic fertilisers, minimising the use of artificial inputs on the farm. Francisco says that what has been most interesting for him has been working together with the weather conditions in order to create the best possible raw material; remaining agile, knowing what his plants need and the precise moment to harvest in accordance with the slightly unpredictable weather conditions high in the mountains of the West Valley region. The conditions on the farm are influenced by both the Pacific and Atlantic Oceans, creating this instability, but also an abundance of cool winds, especially during the cherry maturation phase from December to February. The plants have adapted to these difficult conditions, concentrating sugars into the cherries and adding to intensity of flavour in the final cup. The farm is planted mainly with Villa Sarchi and Caturra, but is also home to 12 different exotic varietal plots, which is part of what makes Francisco so excited for the future of Sumava. He mentioned during a recent phone call that his favourite coffee from the farm recently has been a double washed SL28, crisp, fresh and clean. With all of this knowledge and dedication on the farm, Francisco went onto win the 2016 Costa Rica Cup of Excellence, only 18 months after taking ownership of Sumava. The winning coffee was a Caturra lot, processed using an innovative ‘sweet sugar’ process. The water left behind after washing mucilage from coffee seeds during the washed process is often referred to as ‘honey water’ as it is so full of natural sugars from the coffee fruit. To accomplish the ‘sweet sugar’ process, the depulped seeds were first soaked in this honey water before being left to dry with mucilage still attached. This led to one of the highest scores ever given in the competition, a 93.4.

First coffee - Sumava

All the features we love

This lot is also of the Caturra varietal, processed using a rather exacting natural process. While the method used here is interesting, Francisco made abundantly clear to us that the result of a process is never better than the incoming cherry, both in terms of ripeness and sorting. It is due to this that he focuses more on growing conditions on the farm, and keeping a healthy plant stock of high quality varietals. There is an area of the farm with a very thick shade layer composed of pine trees, leading to stable cool temperatures. The cherries in this lot were first laid out in this area for 3 days before being transferred to raised beds, in a process Francisco refers to as ‘cherry reposado’. This translates to ‘dammed’ or ‘paused’, and literally pauses the cherries from beginning to dry, lengthening the entire drying and adding a new level of intensity to the sweetness. When the cherries are transferred to the raised beds, they have just started to dry, but remain juicy, almost resembling prunes. It has all the features we love in Costa Rican naturals, a deep sugary sweetness, and lots of heavy ripe fruit.

Second coffee - Ethiopia

Guji Kercha
A rich natural from Guji

Blueberry, Butterscotch and Grape
(250g / 8.8oz)

We have been purchasing Ethiopian coffees through Moplaco for three years now, and have grown to trust their buying practices and the quality that they are able to offer, both in coffees they produce themselves, and those they purchase and export from neighbouring mills. This lot is an example of the latter. This lot was purchased by Moplaco from the Hasen Sormolo station in the Kercha Woreda. Kercha is located in the Oromia region, which is part of the Guji zone, but located slightly further south than the famous coffee producing spine of Yirgacheffe, Chelelectu and Gedeb. Hasen Sormolo is a privately owned washing station, and gathers coffee from approximately 2000 smallholder producers over a harvest season. This small lot was processed using a careful natural process, with extensive sorting and turning, especially during the first few days of drying. This has helped to create a soft and rich cup, with perfumed aromas followed by notes of ripe fruits and a creamy caramelised sweetness.

The Natural Process

For this month’s subscription, we are focussing on a single method of post-harvest processing, one which has rather different applications and connotations in different parts of the world. The basic premise of a natural process involves drying the coffee seed all the way to an exportable moisture content while still inside the cherry. The cherry and parchment layer surrounding the seed are then removed at the dry mill before export. As fermentation is occurring throughout the entire drying process, often open to the elements, controlling the process carefully can lead to very different profiles in the cup.


It is thought that the very first natural processes actually happened on the tree, with coffee cherries allowed to dry completely without being picked. Some coffee producers have tried to recreate this process in recent years, but the level of risk is very high, as wind and rain can cause the drying cherries to simply fall to the ground, rendering them useless. Across much of the coffee belt, the chances of heavy rains or strong winds are high during the several weeks this process takes to complete. There is very little documentation for the beginning of picking ripe fruit and drying in a more controlled manner, but it is thought to have started around the time coffee became a cultivated crop, after seeds were taken from Ethiopia to Yemen around 500 years ago. Today, especially in Ethiopia and Kenya, the vast majority of naturally-processed coffee is of lower quality, either for the internal or the commodity market. In Ethiopia, around 80% of coffee is naturally processed, with exportable speciality natural lots making up a very small proportion of this. In Kenya, naturally processed coffees are mainly off-grade lots known as M’buni, made up of under- and over-ripe cherries removed during the sorting process. In many Central and South American countries, where more affluent producers have more control over their output and are better able to take financial risks, natural processing has become popular as a method of differentiation. In fact, many of our producer partners have reported that the specialty market is demanding a greater proportion of naturals than ever, as roasters chase the wild and distinctive character the process brings to the cup.

A new era of Natural

To create very high quality naturals requires a different level of care than simply leaving cherries to dry in the sun. The two main challenges are controlling the level and evenness of the fermentation, and sorting. As cherries are fermenting throughout the long drying process, with a great deal of oxygen, sugar and moisture available, the chance of over-fermentation or mould formation is high, bringing acetic taints and off-flavours into the cup. This can be avoided by turning cherry often to aid even and timely drying, or even by using mechanical drying, where cherries are effectively placed in a giant tumble dryer. The effect of rain and excess moisture can also be catastrophic, so drying beds are often covered with a tarp during rain showers and cool damp nights. Another disadvantage of traditional natural processing is the lack of steps where sorting can take place compared to a washed process. Often quality-focussed producers will reintroduce these steps, such as by floating cherries in clean water in order to remove any foreign material and low density cherries. It is very difficult to spot defects once the cherries start to dry and darken in colour, so extensive sorting is vital during the first few days of drying. All of these steps together can lead to clean and transparent naturally processed coffees, without the risks of poor sorting, or over-fermentation.

Flavour creation

Once all of these important factors are taken care of, the conditions during drying come into play, shaping the character in the final cup. For example, in the dry and warm conditions of the Cerrado Mineiro in Brazil, naturals dry rather quickly, minimising fermentation and its effect on the final cup. We recently discussed processing with Adam Overton of Gesha Village in Ethiopia, and they aim for a similar clean profile by drying cherries in very thin layers, reducing drying times. Adam also mentioned that himself and many other producers know exactly when to process naturals during harvest, for example based on weather conditions. For example, after a period of dry weather, there will be very little moisture present in the cherries, reducing the amount of sugary mucilage present and therefore the drying time. For the lot we are sharing this month, Francisco Mena had almost the exact opposite intention, using a creative method to slow fermentation in a controlled manner in order to soften out the cup and create a ripe and creamy profile, without introducing any off-flavours. Read more about his method below.

Two contrasting cups

The natural process has gained in popularity across the entire coffee belt in recent years. While the term is widely used, and the premise of the process widely understood, it is applied in very different ways by different producers in different parts of the world, giving very different results. The coffees we’re sharing this month are both very high quality examples, but differ in terms of the raw cherry used and the way the process is carried out. This leads to two contrasting cups, that we hope you enjoy this month.

Stay bright and curious - John Gibson

About Discovery

About Discovery

The opportunity to share new experiences

Our Discovery Subscription allows us the opportunity to share new experiences with you every month, taking you with us on our journey through the changing seasons of coffee. This allows you the opportunity to taste new lots from across the coffee landscape as they arrive at our roastery, when they’re fresh and in season. We strive to find the most delicious and thought-provoking coffees we can get our hands on, working together with a group of innovative and dedicated partners we have met over our years in the industry. We are inspired not only by sharing their painstakingly created raw material, but by conveying how each step of its journey has led to what you find in your cup, be it terroir, varietal, post-harvest processing, or something else entirely.

We always aim to tell a story

One of the best ways to appreciate the effect of these factors is to taste coffees side by side. Our most popular option allows you to experience two coffees every month, maybe different varietals or processes from the same farm or region, or maybe two parallel lots from producers at opposite ends of the coffee belt. We always aim to tell a story with our coffee choice, focusing on a different aspect of what we’re finding exciting in coffee right now. Sharing these experiences each month allows us to expand our coffee horizons together, and develop a shared vocabulary within both taste and preference in coffee.

We’re always happy to continue our conversation with you through our webshop portal, whether it be purely practical, or discussions about this month’s coffees. We see our role as simply a middleman between you and some of the best coffees in the world, and the people who produce them. These people inspire us, and we do our utmost to share both their coffees and their stories with the people who appreciate them most.