Tag: coffee processing

Coffee Processing

Written by David Stallings, head of Roaster and Importer Relations

As an industry, the term “coffee processing” refers to how we remove the seeds from a coffee fruit. How any given coffee is processed is important because of the fact that processing can have a strong impact on the flavors found in the finished cup of brewed coffee.

Though we colloquially refer to coffee as “beans,” this is botanically inaccurate. Coffee is the seed of a fruit. To be more exact, the coffee fruit is a drupe or stone fruit. Unlike other stone fruits, such as peaches or cherries, which possess relatively large mesocarps (the pulp or edible portion of these fruits), the coffee fruit possesses an incredibly small mesocarp. This means that the coffee fruit is not particularly well-suited to being eaten (by humans or even most animals). Through the ages we have, of course, found an equally pleasurable use for this fruit: coffee seeds are removed from the fruit, after which they are roasted, ground, and brewed into the decoction known as coffee.

Coffee Processing

We can talk about two broad categories of coffee processing: coffees that are pulped prior to drying and coffees that are not pulped prior to drying. Here, “Pulping” refers to removing the leathery skin of the coffee fruit, along with some fruit mucilage.

Infographic by David Stallings

Regardless of the method used to separate the seeds from the coffee fruit (i.e. regardless of how the coffee is processed), it is critical that the coffee seeds be dried. As with many produce items, coffee seeds that have not been adequately dried could develop mold. Further, proper drying is critical for retaining the freshness of the coffee for the longest possible period of time. If a coffee is not properly dried, it could taste “old” (papery, woody) much faster than if the coffee was dried properly. As such, and interestingly enough, the terms “age” and “old” are fairly relative in coffee and have more to do with how a coffee is tasting, as opposed to how long it has been since the coffee was harvested. A coffee that is three months off harvest can taste “old” if it was not dried properly, while a coffee twelve months off harvest can still taste quite fresh.

Natural Processing

Coffees that are not pulped prior to being dried are typically referred to as Naturally Processed or Dry Processed coffees. To produce a Naturally Processed coffee, which happens to be the original processing method (due to its innate simplicity), one simply harvests the (ideally ripe) coffee cherries and dries the entire fruit. The coffee then remains on drying tables until the target moisture content is reached.

During this time the coffee fruit is turned at regular intervals to ensure even drying and to avoid any pockets of moisture from remaining that could encourage microbial proliferation. Naturally Processed coffees tend to be very fruit-forward and sweet, generally with lower perceived acidity. The distinctly fruity flavor profile of these coffees tends to be polarizing: some people absolutely love the character while others find it off-putting. Though ostensibly simple, producing clean Naturally Processed coffees is incredibly challenging. We wrote about that fact in this Instagram post back in November of 2020.

Fully Washed Processing

Coffees that are pulped prior to being dried can fall into two primary categories: Fully Washed and Honey. Fully Washed – also known as Washed, or Wet Processed – is the older and more popular of these two processing methods and involves pulping the fruit and then placing the mucilage covered seeds into a tank and allowing the mass to ferment. The fermentation taking place is dependent upon microbes found in the air and on the coffee plant consuming the sugars of the coffee fruit.

Yeasts and bacteria break down the sugars of the mucilage and the stubborn pectin layer immediately surrounding the seeds. After these layers are broken down, the mucilage is easily washed away and the coffee seeds, still covered in a protective parchment layer, are sent to drying tables to be dried to the target moisture-level. Fully Washed coffees tend to be clean, balanced, and present a sparkling acidity that can drive and inform the perceived sweetness in the finished cup.

Honey Processing

Existing somewhere between Fully Washed processing and Natural processing, the Honey processing method (also referred to as Pulped Natural) was developed by coffee equipment manufacturer Pinhalense in the 1990’s. The goal was to produce a coffee that struck a balance between the sweet, heavy-bodied character of a Naturally Processed coffee and the balanced cleanliness of a Fully Washed Coffee.

Honey processed lots begin by being pulped, like a Fully Washed process coffee. After pulping, however, the coffees skip tank-fermentation and mucilage removal and head directly to the drying tables, mucilage and all. A bonus of this processing is the small amount of water used when compared to Fully Washed coffees. We wrote about Honey Processed lots in an Instagram post back in November of 2020. That post can be found here.

When produced carefully, Honey processed lots can be very clean and elegant. In our experience, however, they can also lack both the fruited complexity of a Naturally processed coffee and the expressive acidity of a Fully Washed coffee. Over the past two years we have experimented with various ways to produce Honeys that remain clean but are also more expressive. We will share more about those processes in an upcoming blog post!

July 30, 2021
The realities of coffee harvest in Burundi
A conversation with Long Miles co-founder, Ben Carlson.

It’s always been our vision to be transparent about coffee harvest and production in Burundi. While our mantra is to hold on to hope despite any challenges we might face, the realities of this year’s coffee harvest has stretched our team and the coffee communities that we work with.

Why was coffee harvest in Burundi small this year?

BC: It’s a complex answer. Like our friend and former Managing Director, Lauren Kagori (née Rosenberg) likes to say, “In Burundi, simple is complex and complex is simple.” Overall, there are four things that I would say contributed to the size of Burundi’s harvest this year.
1. Soil health. The World Bank recently released a report focused on unpacking climate fragility in Burundi. According to their research, Burundi loses almost 38 million tons of soil and 4% of its gross domestic product to land degradation every year. Half of the households in the country depend on coffee for their livelihoods. The coffee sector alone brings in 90% of the country’s foreign revenue, but over the last forty years severe soil erosion has led to a two-thirds decrease in coffee production, pushing millions back into poverty;
2. Fertilizer. We can’t access fertilizer in the country, and it’s illegal to purchase it outside of Burundi. You can only purchase fertilizer from one semi-privatized company in Burundi, but they don’t produce a fertilizer meant for coffee. Usually, we have to place an order for and purchase fertilizer through Burundi’s national coffee board, ODECA (translated from French as “Coffee Development Office”). From our experience, the delivery of fertilizer is always delayed and never available in the quantities that we need;
3. Rain. It’s apparent and out of our control. The rainy season in Burundi typically runs from the end of March/beginning of April through May, but over the last three years the rains have stopped just before May. If we had healthy soil and fertilizer, the rain could have stopped and the impact on the coffee crop might have gone unnoticed;
4. Old coffee trees. A majority of the coffee trees in Burundi were planted between the 1930s and 1960s under Belgian colonial rule. The newest coffee trees were most likely planted in the 1980s. We’re talking about coffee trees that are about forty-years old! Generally speaking, coffee trees should be replaced every fifteen to twenty years. When we introduced our inaugural pruning campaign and encouraged partner coffee farmers to stump their older coffee trees, it was incredibly difficult to get them on board. It still is! Up until that point, stumping coffee trees was unheard of.
“In Burundi, simple is complex and complex is simple.”

What did we expect this coffee harvest, and what did we actually get?

BC: We expected 1.2 million kgs of harvested cherry. The reality is that we might have reached 500,000 kgs. That’s less than 50% of our expected production, which means 50% less revenue for the farming communities that we work with. Added to this, we’re coming off the back-end of a low harvest in 2020 which means that coffee farmers in Burundi should have experienced a peak in production this year. This all goes back to cyclicity. In 2019, we hit 20% of our average production. In 2020, we hit 50%. This year, the country as a whole hit between 40-45% of its average production.

We were hoping to do more controlled (anaerobic-styled) fermentations using our newly shipped Jacky Bin technology, which we’ve ended up doing but not in the quantity that we expected. With shipping delayed worldwide, our Jacky Bins took much longer than expected to get from Australia to the Dar es Salaam port. They then needed to be trucked from Tanzania across the border into Burundi where they took a couple of weeks to clear customs before our team could eventually collect them. Needless to say, the Jacky Bins got to our washing station a few weeks shy of the end of harvest. We missed the mark there, but are excited to grow this side of our coffee production in the future.

Our goal was also to increase the number of coffee farming families that we work with to maximise our impact, but the number of farmers delivering to our washing stations this season has actually declined. Most farmers across the country have produced between 25-40kg of cherries this season. When you’re producing this amount of cherry, it’s not worthwhile processing and delivering to any washing station.

Is this an issue that just Long Miles is facing?

BC: No, this isn’t a Long Miles thing. It’s happening to coffee producers country-wide.

Every coffee harvest has surprises, both good and bad. Are there any this year that you want to share?

BC: Over the last two years, there’s been a new coffee authority, ODECA, regulating the coffee sector. This kind of turnover happens regularly in Burundi. ODECA has taken over a majority of previously privatized washing stations. With the last three years being low production years, farmers haven’t delivered high yields to their washing stations which means that ODECA hasn’t processed much coffee. Added to this, privately and co-operative owned washing stations were paying a higher price than semi and government-owned washing stations like ODECA’s.

In what we presume is an attempt for them to find more equity, they banned transit centres. This has meant that washing stations have had to collect coffee only from the farmers adjacent to their stations, or those farmers willing to travel further to reach them. In some ways, this is helpful as there’s a better concentration of coffee and farmers who have more direct access to the market.

This is no surprise, but Burundi is a landlocked country. We’ve often faced challenges to get coffee out of the country timely, but in times like these it can take even longer to export coffee. We also can’t dry mill coffee on our own. Applying for a dry mill licence is surrounded by incredible bureaucracy and red tape in Burundi, and there aren’t many options when it comes to where we can mill our coffee. In previous years (this one included), our team has travelled the country looking for options. The dry mill that we’ve previously used is struggling to renew their licence this year, and there are a landslide of challenges that follow suit from this.

“…this isn’t a Long Miles thing. It’s happening to coffee producers country-wide.”

What does all this mean?

BC: This is possibly our best harvest quality in the nine years that we’ve been producing coffee in Burundi. The improved quality of our coffee could be due to the low harvest over the last three years. If you were to draw a comparison between coffee and wine production, this kind of thing sometimes occurs on wine estates that are producing wine from older vineyards. We’re really excited about the coffees that we’ve produced and are working with the same hills, but the reality is that we’ve produced smaller micro-lots this year.

Sourcing coffee is also a unique challenge this year. Previously, we’ve sourced coffees from neighboring producers that have stood out to our team on the cupping table. This year, coffee is limited country-wide so it’s looking like sourcing coffee won’t be possible.

“The sobering reality is that our combined coffee production in 2019, 2020 and 2021 don’t add up to our coffee production in 2018.”

Our team is trying their best to make sure that all our partnering roasters get coffee, but we’re not going to be able to meet everyone’s demands this year and expect to be able to offer less coffee across the board. The sobering reality is that our combined coffee production in 2019, 2020 and 2021 don’t add up to our coffee production in 2018. Knowing the realities of coffee production in Burundi, we’ve recognized the need to be versatile which is one of the reasons why we’re expanding our operations in Kenya and Uganda.

Even thought this year’s coffee harvest has been challenging to navigate, we are incredibly grateful for the coffee communities that we work with and the continued support from our roasting partners across the globe. Thank you. We’re excited to share this year’s coffees with you!

Do you have any questions about this year’s coffee harvest in Burundi? Please get in touch with us!

Contact Us
July 23, 2021
The roads to coffee production at Long Miles Coffee

Every coffee that is picked and processed needs a home, which is why coffee production takes different roads within our company.

Raised drying beds at Bukeye Washing Station in Burundi

The first road, modeled in Burundi, includes washing station ownership. In Burundi, we work with 5,500 smallholding farmers- who each grow less than a bag of coffee per annum- to produce and bring to market the coffee they grow. To accomplish this, we own three washing stations and work with farmers on eleven unique hills. Another crucial part of this model is farming. We own coffee farms that stand alongside our smallholding farmers. These farms act as model farms for the surrounding communities as well as give us a chance to experiment with and control some of the variables in growing coffee.

Haron Wachira and Ben Carlson hand-sorting coffee at Thunguri Washing Station in Kenya

The second road coffee production takes within our company is partnership. In Kenya for example, we are partnering with Haron Wachira to rehabilitate and refurbish the Wachira family’s dormant coffee factory and farm located on Mount Kenya, in Kirinyaga County. In our first season, we worked directly with thirty coffee farming families who live in the community. While the Wachira Group is not solely focused on coffee, we share the same vision of working with small-scale coffee farmers to improve their production, access to markets, and the price paid for their coffee.

Raised drying beds at Heza Washing Station in Burundi

We can’t control how much coffee is produced in a season, which is why the third road that coffee production takes at Long Miles is sourcing from partnering coffee producers. Our intention is always to produce our own coffee, but some years we will also share coffees from local partnering coffee producers that have stood out to us on the cupping table. Partnering with these coffees enables us to continue year-round projects and programs that have become essential to who we are, whether that is our team of Long Miles Coffee Scouts, our Trees For Kibira reforestation project, or running Farmer Field Schools– to name a few.

No matter which of these roads we take, our end goal is the same: producing excellent coffees, uplifting the smallholding farmers who grow them, and meeting you, our roasting partners, where you’re at. You might already know this or be familiar with these names, but these are the coffees that our company produces:

Long Miles Micro-lots

To us, micro-lots are coffees that have been carefully curated based on two primary factors: traceable down to a distinct geographical locale where the coffee was grown, and a cup score of 86+ designated by our team. Each delivery of coffee cherry that we receive from our partner farmers at one of our washing stations is sorted and processed differently, depending on the country of origin.

Kibira Micro-lots

Kibira micro-lots are coffees that have been processed by coffee producers surrounding our Long Miles Washing Stations. Our cupping lab and quality control team cups through many dozens of lots in order to find the best coffees to partner with. We source these 86+ scoring coffees knowing that at every step of the way they have been processed according to the Long Miles Coffee standard. Partnering with these coffees enables us to continue programs that have become essential to who we are, namely the Long Miles Coffee Scouts and Trees For Kibira.

Kibira

Kibira lots represent coffees that have been sourced from partnering coffee producers. These coffees, ranging in quality and price, are tailored to your needs based on pre-harvest conversations and are typically contracted in larger quantities.

Hills

Our priority is to produce coffee that is of micro-lot quality, yet some of the coffees that we process fall slightly below the 86 mark designated by our team. Coffees that score between 84-85 points, are blended together and are traceable by washing station and called “Hills.”

If you have any questions about our coffee, please get in touch!

May 25, 2021
On fermentation

Written by David Stallings, head of Roaster Relations at Long Miles Coffee.

Fermentation is an incredibly complex process. The purpose of this blog post is not to present an exhaustive scientific perspective on coffee fermentation. We are coffee producers. We are not researchers, nor do we have a background in microbiology. The purpose of this blog post is to address some basic aspects of fermentation, as they pertain to coffee processing. If you are looking for an exhaustive scientific approach, there are people doing great work and research surrounding fermentation and coffee processing. One individual, in particular, that we would recommend checking out is Lucia Solis.

As an industry, we use the term “processing” to refer to the method by which coffee seeds are removed from the fruit in which they developed, in order to prepare them for export. Coffee seeds are, of course, what are colloquially referred to as coffee “beans”. However, they are not beans in any true botanical sense. That is to say, it’s the seeds which we roast, grind, and brew into the decoction known as coffee. In order to separate the seeds from the fruit, and do so in such a way that the seeds are stable and will not encourage microbial growth (bacteria, mold, etc), the seeds must be dried to a certain degree. As such, these are the two primary functions of processing: to dry the coffee to a stable level and to remove the seeds from the fruit.

Washed Processed coffees on drying tables at the Long Miles Coffee Washing Station

There are two broad processing categories under which these goals can be attained (and there are many sub-categories under these broad classifications which we’ll write about another time.) Natural, or Dry Processed, coffees are ones in which the seeds are allowed to dry inside the coffee fruit itself. Not long ago we talked about Naturally Processed coffees on Instagram – you can find that here.

Natural Processing is the original coffee processing method and is well suited to regions with a very dry harvest period. Before export, the dried fruit is broken open (mechanically) and the loosened seeds are sorted out from this. While ostensibly quite simple, producing Naturally Processed coffees in a way that is free from taste defects can be very challenging. This is especially true for producing countries or regions which have a very humid or rainy harvest period. In our experience, Burundi is particularly challenging in this regard. This is because the potential to produce top-quality Naturals is quite high. That said, some harvest seasons can be unpredictably wet, a problem increasingly exacerbated by a shifting climate.

Pulped coffee undergoing the Washed Process

These challenges surrounding drying the coffee without taste defects led to the development of the Wet or Washed Processing method long ago. In the Wet Processed method, the outer skin of the coffee fruit, along with some mucilage, is removed. At this stage, the coffee is fermented in order to remove the remaining mucilage, along with the stubborn pectic layer that surrounds the seeds. As such, when we talk about coffee fermentation, we are referring to a step in the Washed Processing method. After fermentation, these layers are easily washed off, allowing the coffee seeds to be dried. Since the vast majority of the available glucose and fructose is removed through this process, it is much easier to dry the coffee without encountering unwanted microbial activity that may lower the quality of the final product.

Up until fairly recently, this was viewed as the entire scope and purpose of fermentation: to clean the coffee, removing the seeds from the mucilage and pectin inside the coffee fruit. The process was not considered (by most) to impart any positive or even identifying flavors into the final product. In fact, many spoke of the goal of washed coffee in a similar way that some roasters speak of lightly roasting coffee: the process was one in which the goal was simply to add no negative flavors and to let the coffee “speak for itself,” as it were. In fact, the process of fermentation was considered so strictly functional and oblique as it pertains to coffee flavor, that machines were developed to mechanically remove the mucilage from the coffee, without the fermentation step. Carlos H. J. Brando writes in Wintgen’s seminal 2004 book, Coffee: Growing, Processing, Sustainable Production_¹, that, “although a lot of research work has gone into demonstrating that fermentation and mechanical removal of mucilage lead to the same quality results, some experts are still skeptical.” Elsewhere in Wintgen’s tome is the mechanical removal of mucilage as being able to produce the same quality coffee as traditionally fermented coffee, spoken of as fact.

While it is true that coffee seeds themselves do not actually undergo fermentation (only the mucilaginous material surrounding the seed), there has been a growing movement from researchers indicating that yes, fermentation does affect the flavor of the finished coffee. This has been noted anecdotally by some coffee professionals who have experienced a shift in coffee quality and complexity in production systems that previously employed traditional fermentation and have moved towards mechanical washing that does not require the coffee to be fermented. It has also been examined by individuals such as the aforementioned Lucia Solis.

Members of the Long Miles Coffee team stand alongside a soaking tank with fermenting coffee

Once coffee is pulped and exposed to microbes, these yeasts, bacteria, and fungi eat the glucose and fructose, along with some naturally occurring organic acids, found in the coffee fruit. During this process, fermentation by-products are created. These bi-products can penetrate the coffee seeds, affecting the final cup quality and qualities. Traditionally, the microbes present are naturally occurring and come from the environment – being found in the air, within the fermentation tanks, and also on the coffee fruit itself. In recent years, yeasts have been developed with a specific aim of modulating a coffee’s flavor profile. This is something we experimented with back in 2018 and may explore more in the future.

Even without the addition of selected yeasts, a number of factors can influence fermentation. Chief among these are temperature and the presence (or lack) of water. Warmer environments will speed up the fermentation process whereas cooler environments will draw out the process. It is for this reason that fermentation as a step in processing can never be based purely on a set amount of time. Our own experience fermenting coffee in Burundi these past eight years confirms this. To achieve a fermentation in which all the mucilaginous material has been fermented away can, for example, take eight hours in a warm climate, or thirty-six plus hours in a cooler climate for the exact same lot of coffee. It is true that over time one is able to have a target fermentation time based on the tank size, average temperature, etc. That is to say, with experience specific to any given washing station, one is eventually able to assume target fermentation times. But to enter into a new or unknown system and design a fermentation protocol based on time, rather than observing the process and progress of the fermentation as it is happening, would be putting the cart before the horse.

If the fermentation takes place underwater, the temperature of the fermenting mass is typically cooler than it would be without adding water. As such, this generally slows fermentation down. There is, however, another factor that is more important in influencing the final cup qualities. Coffee that is being fermented underwater is more conducive to bacterial proliferation. Coffee that is fermented dry is more conducive to yeast fermentation (though acetic acid bacteria is present in both circumstances). In our experience, fermentation which happens underwater also has the added benefit of being more homogenous. We can only assume this is because the fermentation bi-products which influence the cup quality are more evenly distributed via the water.

Naturally Processed coffee on drying tables

Though we have discussed fermentation as a step in the Wet or Washed Processing method, it is important to note that fermentation also technically happens in Naturally Processed coffees. Within the skin of the coffee fruit itself, mucilage ferments once the coffee has been removed from the shrub on which it grew. The fermentation process within a Naturally Processed coffee is very likely bacterial as bacteria is significantly smaller than yeasts and, thus, more likely to make its way inside the fruit. This highlights why it is so critical for the initial drying of Naturally Processed coffees to happen quickly. If the coffee is allowed to ferment for too long, the acetic acid bacteria will be able to negatively impact the final cup quality by producing strong acetic acid flavors (think apple cider vinegar). Some acetic acid is always present in coffee and this is a good thing as it can lend a fruited complexity to the final product. But, too much acetic acid leads to off, rotten, or “over fermented” flavors that are eschewed by most specialty coffee professionals and consumers alike.

References

_¹ Wintgen, J.N. 2012, Coffee: Growing, Processing, Sustainable Production: A Guidebook for Growers, Processors, Traders and Researchers, Second, Revised Edition, Wiley-VCH, Weinheim, Germany.

April 21, 2021

scroll to top

error: