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Specialty Coffee Blog by Volcanica Coffee

The New Coffee Processing Methods on the Block

by Aaron Contreras 16 Nov 2022 0 Comments

All coffee is a processed commodity that requires hundreds of hours of human labor from seed to cup that has traveled thousands of miles just to get in your cup.

And while there are many different factors that influence taste, such as nutrients in the soil, roasting, brewing, exposure to sunlight, exposure to rain and the elements, one of the most important factors that plays into how your coffee tastes each morning is how the coffee is processed.

What do we mean when we say processing? I’m so glad you asked. 

Coffee processing refers to the various methods by which the seed, what we often refer to as the bean, is extricated from the coffee cherry. Much like other types of cherries that you’re familiar with buying and seeing at the grocery store, coffee cherries contain a seed, pulp, and mucilage that need to be removed. But unlike other cherries, coffee cherries’ seeds taste wonderful when removed, processed, cleaned, and then eventually roasted.

These different methods of processing the coffee affect the flavor because it modifies the cell structure of the beans and ultimately determines how we as roasters approach how we end up roasting the beans when they arrive.

Traditionally, there have been four primary ways to process coffee: natural process, washed process, honey processed, and wet hulled (or what sometimes gets referred to as semi-washed processing in some circles). With the advancement of studying coffee intensely and up close for the past thirty years or so, a handful of new processes have begun to pick up steam in popularity due to the wild and exotic flavors they enhance and produce within the coffee beans. Some of these include carbonic maceration, wine yeast process, anaerobic fermentation, lactic fermentation, and many, many more.

Before diving into some of the more experimental processes of coffee, we first want to delve deeper and give a concise definition of the four traditional methods to give you a better understanding of coffee processing and production in general.

Natural Processing of Coffee

Natural processing of coffee is perhaps one of the more traditional methods, and is often referred to as the dry process. The process involves drying the handpicked coffee cherry when the cherries are at optimal ripeness, typically when they have turned either a different shade of red or sometimes even yellow depending on varietal.

Producers must dry the coffee immediately after being picked so as to avoid the fruit spoilage, which can and does lead to the coffee cherry tasting moldy and defective. The cherries are placed on drying beds optimally located under the sun with little to no shade.

The entire drying process for natural processed coffee can take anywhere from 3 to 6 weeks, during which the producers must consistently rake the cherries to rotate and ensure an even, consistent drying throughout the fruit, while also preventing spoilage. While the beans sit in the coffee cherry fruit, the sugars and pectin and other parts of the coffee cherry are breaking down and naturally fermenting the coffee beans inside. This ultimately leads to a sweeter, nuanced flavor profile that has a wide range of different notes depending on many different factors.

Natural processed coffees, like our Costa Rica Natural, have a sweet, fruity taste, with complex notes of tart blackberry jam and a peach-like acidity that developed due to the extra time and care that went into drying and processing the coffee. Natural process can be a tricky and labor-intensive process that, if not properly developed and raked, could lead to the coffee spoiling in the cherry even before it's fully processed. But we believe the extra effort produces a wonderfully complex and tantalizing cup that is sure to delight any palate that enjoys bright, wonderful notes.

Washed Process Coffee

Perhaps the second most common forms of processing coffee is known as the washed, or wet, process. This process, as you might have guessed it, refers to the amount of water and “washing” required to produce the final product. While it can lead to a clean, uniform cup of coffee, it has been, and continues to be, criticized as a method of processing coffee due to the excessive and sometimes wasteful use of water. But advancement in technology and knowledge have led to the water used in washed process coffee to be recycled and reused by rebalancing the pH level that has resulted in a more environmentally forward thinking process.

Producers must first sort handpicked coffee cherries to ensure only the ones at perfect ripeness go through the processing to ensure a clean, uniform cup. This is done by putting the cherries through a sorter than measures the coffee cherries’ density. Once sorted, the washed process involves removing the fruit’s skin from the bean with a mechanical depulper before they are dried. After being depulped, the coffee beans are ready to be placed in a water tank to ferment and remove the remainder of the fruit’s anatomy (e.g. mucialage, exocarp, silver skin). The fermenting step typically takes anywhere from 24-72hrs, and depends heavily on climate, altitude, and varietal.

Once ready, the coffee beans are then washed in order to remove any remaining particulates and material from the bean. Then the beans are placed on beds and/or patios to dry out in the sun, much like how natural processed coffee is dried. However, unlike natural processed coffee, washed processed coffees don’t take nearly as long to dry out due to the fruit and mucilage having been removed.

Our Ethiopian Kochere is an excellent example of a well-balanced, clean cup of washed process coffee. While highlighting some interesting plum and black currant sweetness, our Ethiopia Kochere also features a well-rounded mouthfeel with a cocoa finish that comes from the processing of the coffee. The acidity in washed process coffee tends to be cleaner and not as bright (like the difference between orange juice and lemonade). 

Semi-Washed Process Coffee

Semi-washed coffee is often referred to as wet hulled coffee. It is also referenced as a bit of a split between natural and washed processing. There is, however, a bit of a difference between semi-washed and the aforementioned processes. 

Once picked, coffee cherries go through depulping machines to remove the seeds. Those seeds are then placed in plastic tanks with the mucilage still intact to retain the moisture. The beans are then ‘hulled’ to remove the remaining mucilage and exocarp and laid out on drying beds.

The semi-washed process is most commonly utilized in islands across Indonesia, which has given the coffee from the region its emblematic earthy, spice-like flavor notes. The reason why the process is so common in Indonesia is due to the humid climate that makes drying the coffee more difficult, while also requiring significantly less infrastructure and water like the washed process does.

If you’re looking for a staple of semi-washed processed coffee, then look no further than our Sumatra Mandheling coffee, which features savory notes of maple and earthy undertones that has a clove spice finish. The coffee’s heavy body comes from the processing that has influenced how we go about roasting the coffee. Semi-washed coffees do also tend to be best enjoyed as either a medium or darker roast to bring out the body and flavor notes.

Honey Process Coffee

Honey processed coffee uses a bit of a combination of natural and washed process methods, but is far more labor intensive and not nearly as commonly utilized by producers. Despite its namesake, there is no honey involved in processing the coffee. Instead, the ‘honey’ in honey processing is a reference to the mucilage that is left on the beans as they dry.

The technique to perform honey processing is to depulp the coffee seeds from the cherry, again with the mucilage still remaining on, and then being placed on patio or drying beds to sun dry. The amount of mucilage will determine the type of flavor profile and sweetness in the final product, and is also why you will sometimes see color identifications in the name of the coffee, such as black honey, yellow honey, red honey, etc.

The different color identifications are also an indication of how much extra work went into developing and caring for the coffee as it dried. The darker the color classification, the more intense it was to care for the coffee, since those coffees required much more monitoring to ensure mold or over-fermenting did not occur within the bean.

Perhaps our best example of honey processed coffee is our Dominican Coffee that has gone through a red honey process to bring out bright notes of strawberries, citrus, and a hint of honey. While honey process does require a bit more of intensive care and attention to detail to produce, we believe it does lead to a wonderfully beautiful and exotic flavor profile that works well in many different capacities, including giving blends, like espresso, an extra bite of acidity that can truly brighten up any cup.

The Not So Common Processes of Coffee

As noted earlier, while the aforementioned processes are the most common and commercially viable, they are not the only way to process coffee. And the specialty coffee market has been tirelessly working, experimenting, and developing some interesting and exotic ways to process coffee over the years. For any coffee enthusiast and connoisseur, they are definitely worth a taste, as we believe they will knock your socks off and then some.

Anaerobic Process Coffee

The best way to describe anaerobic process is coffee that goes through all the steps that washed processed coffee does, but rather than being put in open water tanks to ferment, the coffee beans are placed in anaerobic tanks that are oxygen deprived, which leads to the naturally occurring microorganisms and yeast in the coffee to feed on the sugars of the coffee. 

These hermetically sealed and oxygen-free environments that the coffee beans are put through lead to air being pushed out through a valve usually located on the top of the tank. And because there is no oxygen for the coffee to feed on, it begins to metabolize the sugar in the fruit to still produce energy and releases enzymes that develop and change the flavor of the coffee.

There are many different variables that need to be controlled and monitored as the coffee beans developed within these anaerobic conditions, such as temperature, sugar content, pH, and the like, all of which change the end result, and all of which can easily ruin the coffee if not perfectly timed. 

Perhaps the best coffee we’ve ever tasted that highlighted the complexity and nuance of anaerobically processed coffee is one from our Private Estate collection; Colombia Private Estate Coffee, Jardines Del Eden Felipe Arcila, Orange Velvet. The coffee is bright, balanced, and an explosion of flavors, from orange zest to rich lemon drops. Anaerobic processed coffee can be a truly delightful and out-of-this-world experience that we’re sure anyone wanting to push the flavor boundaries and discover how truly exotic coffee can taste.

Carbonic Maceration Coffee

Carbonic maceration is the process of placing intact coffee cherries into a sealed tank of water and then flushing it with carbon dioxide, hence the name. The process is very similar to what grapes go through in the process of making wine, and the end result of carbonic maceration on coffee is a very floral, fruity, and wine-like flavor profile.

The process of carbonic maceration has grown in popularity, especially after Saša Šestić used carbonic macerated coffee to win the 2015 World Barista Championship. The result is a complex, low acetic acid cup with fruity tannins reminiscent of a nice Pinot Noir, with an approachable mouthfeel with sweet notes floral hibiscus the permeates throughout the palate.

As stated earlier, the process involves putting harvested ripe coffee cherries into sealed and airtight tanks, then pumping carbon dioxide, while allowing for oxygen to escape through a valve on top of the tank. This provides a CO2-rich environment that allows for fermentation to come about, and is then heavily monitored to reach the desired aroma and flavor notes.

We are proud to present the carbonic macerated coffee produced by Julio Cesar Madrid, nicknamed ‘Maypop’, and grown in rich, luscious soil of Finca Milan, as part of our Private Estate collection of exceptional and wonderful coffees. We have lightly roasted this one-of-a-kind carbonically macerated coffee to a light roast to bring out the tropical pineapple notes with hints of jasmine and hibiscus that has a well-balanced mouthfeel and body.

Wine Yeast Fermentation Coffee

Wine yeast fermentation is another one of those experimental fermentation processes that have come about within the past decade that is heavily influenced by wine and beer fermentation processes. It is constantly developing, with many smallholder producers developing their own style and flavor characteristics unique to just their farm as a way to stand out.

Typically, wine yeast fermented coffees go through dry anaerobic fermentation in airtight tanks or barrels for hours or days. During that time, producers will carefully add different types of fruit pulp and wine yeast to the tank to produce wild and exotic flavors.

While the process is fairly new, wine yeast fermentation has already produced some amazing and award-winning cups of coffee. Perhaps our favorite that we’ve come across is one that we are proud to showcase in our Private Estate collection, produced on Hacienda La Pradera by Oscar Daza in Colombia. The coffee is harvested at optimal ripeness and then anaerobically fermented with passion fruit pulp and wine yeast added to the barrels to produce a rich explosion of flavors that are sure to dazzle and delight your palate. 

What to Make of New Coffee Processes?

All of these new and amazing processes and ways to develop different, unique flavors in coffee can seem overwhelming. Trust us, we here at Volcanica have over a combined three decades worth of experience in the coffee industry and we sometimes get lost in the noise of how each coffee was processed.

The push to develop new fermentation processes in coffee has largely been inspired by what has been happening in the wine and beer industries for the past century. It has only been within the past 10 or so years in which coffee fermentation experiments have started to take place to create unique and new experience; to make specialty coffee truly special. 

These differently fermented coffees might not be your everyday, go-to coffees. But we believe that every coffee connoisseur will find something to enjoy in at least one experimentally processed coffee, whether you enjoy fruitier coffees, like our new Pineapple Honey Processed coffee, or whether you enjoy a delightful tea-like quality, like that found in the Sudan Rume coffee produced on Finca La Inmaculada. There is something for every palate, especially in the experimental fermentation coffees that will truly expand the experience of coffee drinking forever.
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