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Washed Process Coffee

Washed Process Coffee: From Harvest to Green Coffee Beans

By Coffeenated Stories | 14 min read

Updated On: NOV 19 2023

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Coffee, a beloved beverage enjoyed by millions worldwide, has a remarkable journey from the coffee cherry to the delightful cup that awakens our senses each morning. Have you ever wondered how those beans undergo such a transformation? The answer lies in coffee processing, a crucial stage determining the final brew's flavor, aroma, and overall quality.

One of the most widely used and revered methods of coffee processing is the "washed" or "wet" processing method. Washed (Wet) coffee processing is a method that coffee producers use to wash away the layer of mucilage that covers the de-pulped seeds (beans) of a coffee cherry using a substantial amount of water. This technique is celebrated for its ability to produce clean, vibrant, and nuanced flavors in the coffee beans, making it a preferred choice for specialty coffees cherished by coffee enthusiasts and connoisseurs.

Washed (Wet) Coffee Processing
Washed (Wet) Coffee Processing
Image by chrispie from Pixabay - URL: https://pixabay.com/photos/parchment-coffee-coffee-coffee-beans-581355

In the following sections, we will explore the wet processing method and uncover the science and artistry behind each stage. We'll learn how these steps interact to influence the final flavor profile and why the journey from cherry to cup is a testament to coffee producers' dedication to delivering an exceptional coffee experience.

Washed Process Coffee Beans

Oak & Bond Coffee Co. Colombia Single Origin Coffee

Oak & Bond Coffee Co.'s Single-origin Coffee perfectly captures the essence of Colombian coffee craftsmanship. This Washed Process medium roast offering boasts an exquisite blend of flavors that promises to delight coffee enthusiasts across all brewing methods.

Oak & Bond Coffee Co. Colombia Single Origin Coffee
  • Oak & Bond's Colombia Single Origin Coffee is a symphony of taste, featuring fruit-forward notes of cherry pie and berry jam that elegantly mingle with the indulgent embrace of milk chocolate and caramel.
  • Sourced from the revered Antioquia department of Colombia, these 100% single-origin Arabica coffee beans are treated with the utmost care. Expertly roasted to a perfect Medium level that adds depth to the chocolate and caramel notes, creating a uniquely delicious and well-balanced coffee experience.
  • At Oak & Bond, quality is paramount. Rigorous quality control is maintained through frequent sampling and cupping, ensuring that every bag of their single-origin coffee is a testament to excellence.

The Harvest

The journey of creating a stellar cup of washed-processed coffee begins with the critical first step: harvesting ripe coffee cherries. For coffee, ripeness is vital. Not all coffee cherries ripen simultaneously on a single coffee tree; one can find mature (red and yellow) and still-green coffee cherries adorning the same branch.

Ripe and Still-green Arabica Coffee Cherries on a Branch
Ripe and Still-green Arabica Coffee Cherries on a Branch
Image by tk tan from Pixabay - URL: https://pixabay.com/photos/bean-farm-tree-arabica-red-plant-1512433/

This crucial harvesting period usually falls between October and December in most of the world's coffee-growing regions. So, let us embark on our coffee journey to a picturesque coffee farm in November, where the air is filled with the delightful aroma of coffee cherries, and the bustling activity of the coffee harvest is in full swing.

Coffee Harvest
Coffee Harvest
Photo by aleinad _0222: https://www.pexels.com/photo/coffee-beans-harvest-13802102/

As the sun-kissed coffee plantations awaken with the promise of a new day, a symphony of skilled hands commences the meticulous task of coffee harvesting. Amidst the lush green foliage, coffee cherries in various stages of ripeness adorn the branches like rubies on a crown.

Selective picking, also known as selective harvesting or handpicking, is the preferred method for harvesting ripe coffee cherries. Unlike mechanical harvesting, which can be quicker but less precise, selective picking involves skilled laborers who meticulously handpick only the cherries that have reached peak ripeness.

Handpicking Coffee Cherries
Handpicking Coffee Cherries
Image by Daniel Ramirez from Pixabay - URL: https://pixabay.com/photos/coffee-drink-caffeine-cafe-fresh-3923897/

This manual approach allows for the careful evaluation of each cherry's readiness and ensures that only the best cherries are chosen while the unripe ones are left to ripen further. To ensure that only the ripest cherries are collected, multiple rounds of harvesting may be required, typically over several weeks. That prolongs the harvesting process but is necessary to maintain quality.

The harvested cherries then undergo meticulous sorting and preparation, where experienced harvesters discern the perfectly ripe coffee cherries through a keen eye and gentle touch. The sorting process carefully separates the ripe, unripe, and defective cherries, setting the foundation for the washed (wet) processing method. The sorted cherries are cleaned and prepared for the next transformative steps.

Cleaning Ripe Coffee Cherries
Cleaning Coffee Cherries
Image by HAI VAN NGUYEN TONG from Pixabay - URL: https://pixabay.com/photos/coffee-processing-coffee-wet-process-2732895/

Pulping

The cherries meet the Pulping machine in the next stage of the washed coffee processing. With a gentle whir, the machines remove the cherry's outer skin and a portion of its fleshy pulp, leaving behind the precious cargo—the green coffee seeds covered in mucilage. As if emerging from a cocoon, the seeds of the coffee cherries (beans) now stand exposed, their verdant hue shimmering in the sunlight, ready to embark on their journey through time and transformation.

Traditional Coffee Cherry Pulping
Traditional Coffee Cherry Pulping
Pulping Coffee Cherries with Pulping machine
Pulping Coffee Cherries with Pulping machine
Image by carllilo3070 from Pixabay - URL: https://pixabay.com/photos/coffee-coffee-bean-grain-747602/
Image by HAI VAN NGUYEN TONG from Pixabay - URL: https://pixabay.com/photos/washed-coffee-wet-processed-coffee-2744211/

The pulping stage is a dance of precision and care. The coffee beans must be freed from the surrounding fruit, yet the removal must be gentle, preserving the integrity of each bean. The skilled processors, custodians of this art, ensure that the beans are nurtured through the process, cherishing every step of their development.

The pulping stage lays the groundwork for flavor development in coffee beans. By carefully removing the cherry skin and pulp, the coffee beans are exposed but covered in mucilage—the sticky layer surrounding the parchment. This mucilage contains sugars and other compounds that contribute to the coffee's potential for flavor complexity during the subsequent fermentation process.

Fermentation

The coffee beans continue to embark on their transformative journey that will define their unique flavor profile. In this captivating stage of the washed (wet) process, microorganisms and enzymes work in harmony, orchestrating an intricate dance of chemical reactions that unlock the hidden treasures within the beans.

The fermentation process unfolds in the coffee processing station, where fermentation tanks brim with coffee cherries undergoing this obscure process. Here, the magic of fermentation is unleashed as microorganisms, such as yeasts and bacteria, break down the remaining fruit pulp and sugars within the beans. This alchemical transformation is the heart of the washed (wet) process, infusing the coffee with various flavors that will later enchant our taste buds.

The duration of fermentation plays a critical role in determining the coffee's final taste profile. Shorter fermentations preserve the coffee's inherent fruity and floral notes, while longer fermentations intensify acidity and complexity. Thus, skilled processors closely monitor the fermentation process to strike the perfect balance of flavors.

Innovative variations also add to the intrigue of the fermentation stage. Some coffee producers at this stage like to experiment with controlled fermentation techniques, adjusting factors like temperature and water availability to create unique flavor developments. The allure of anaerobic fermentation, where coffee beans undergo a transformation in the absence of oxygen, opens new avenues for sensory experiences. This stage showcases the expertise of coffee artisans who deftly navigate the intricacies of fermentation to craft coffee with distinct flavors.

Fermentation also highlights the concept of terroir in coffee. Terroir refers to the environmental factors, such as soil, climate, and altitude, that influence the flavor of coffee beans. During fermentation, the interaction of enzymes with the mucilage reflects the unique terroir of the coffee-growing region, contributing to the coffee's distinctive and specific flavor characteristics.

Once the fermentation process is complete, the coffee beans are ready for the next step: washing. The beans, now enriched with a myriad of flavor compounds, will undergo a cleansing process that preserves the exquisite taste developed during fermentation.

Washing

Washing is a vital step in wet processing, and its primary purpose is to remove the mucilage—the sticky layer that surrounds the coffee beans—after the fermentation stage. By carefully washing away the mucilage, coffee producers prevent overfermentation and any potential off-flavors, preserving the coffee's clean and delicate taste.

Coffee beans are washed using various methods, and each approach can influence the final flavor profile of the coffee:

  • Fermentation Tanks with Water Flow: In some coffee processing facilities, beans are washed in fermentation tanks or channels with a constant water flow. This method ensures thorough washing and minimizes the risk of reabsorbing undesirable compounds from the fermentation water.
Washing Coffee with Running Water
Washing Coffee with Running Water
Washing Coffee with Running Water
Washing Coffee with Running Water
Image by chrispie from Pixabay - URL: https://pixabay.com/photos/parchment-coffee-coffee-coffee-beans-581355
Image by HAI VAN NGUYEN TONG from Pixabay - URL: https://pixabay.com/photos/washed-coffee-wet-processed-coffee-2744214/
  • Agitated Washing: Another standard method involves filling the tank with water and agitating the beans in water using mechanical equipment. With this method, the beans are gently stirred, encouraging the mucilage to loosen and detach from the parchment, ultimately leading to cleaner beans. This method requires several washing cycles of filling the tank with water agitating the beans, and emptying the water from the tank.
Washing Coffee by Agitation
Washing Coffee by Agitation
Photo by Michael Burrows: https://www.pexels.com/photo/crop-farmer-washing-green-coffee-beans-with-water-7125590/

The washing stage involves water usage, which can have environmental implications. Coffee producers in regions with limited water resources often prioritize water conservation by implementing recycling systems or using water-efficient washing methods. Sustainable water management ensures that the wet processing method remains environmentally responsible.

Once the beans have been thoroughly washed and the mucilage removed, they are now ready for the next step: drying. Proper drying is essential to maintain the beans' quality during storage and export.

Drying

The primary purpose of drying is to reduce the coffee beans' moisture content to a level suitable for storage and export. When coffee beans are harvested, they have a relatively high moisture content, which makes them susceptible to mold growth and degradation. Proper drying is crucial to stabilize the beans and ensure their longevity while maintaining the potential for flavor development.

Sun drying is the traditional method of drying coffee beans. The freshly washed beans are spread out in thin layers on drying beds or patios and left to dry under the sun's natural heat. This method allows for slow and gradual drying, allowing the beans to develop unique flavors during the process. Skilled processors monitor the beans' progress, regularly turning them to ensure uniform drying and prevent mold formation.

Coffee Drying in Pacas Mill, El Salvador
Coffee Drying in Pacas Mill, El Salvador
Photo by Christian Burri on Unsplash - URL: https://unsplash.com/photos/h5qXMqQgJwA

In most coffee-growing regions with abundant sunny days, drying coffee beans last for around 14 days, depending on the weather conditions. During this time, the producers aim to reduce the moisture content of the beans to about 10-12%.

In regions less conducive to sun-drying, alternative methods such as the Wet-Hulled process (Sumatra-processed method) or mechanical dryers are employed. Mechanical dryers are modern innovations that offer controlled drying environments that ensure uniformity in the drying process, providing a reliable and efficient solution. These dryers use hot air or other heat sources to reduce the beans' moisture content rapidly. While mechanical drying offers efficiency, it requires precise control to prevent over-drying and preserve the beans' quality.

Hulling or Dehusking

As the coffee beans near the conclusion of their journey from harvest to export, they encounter a pivotal stage known as hulling or dehusking. This transformative step plays a vital role in preparing green coffee beans for their voyage to consumer countries, where they will be roasted and cherished by coffee enthusiasts worldwide.

Hulling, also referred to as dehusking, marks the moment of revelation—the unveiling of the green coffee beans concealed within protective parchment layers. This process follows the drying phase, during which the sun-drenched beans shed much of their moisture content, setting the stage for the final act of milling.

Green Coffee Beans with Removed Parchment
Green Coffee Beans with Removed Parchment
Photo by Michael Burrows: https://www.pexels.com/photo/heap-of-raw-coffee-beans-drying-in-daylight-7125598/

The initial act of hulling involves carefully removing the dry parchment, a thin outer layer that encases the coffee beans. The parchment acts as a natural protective shell during drying, shielding the beans from external elements and preserving their flavors. As the hulling process unfolds, skilled producers strip away the parchment, exposing the green beans—a moment of anticipation, much like the unveiling of a masterpiece.

Traditional Removal of the Parchment Layer
Traditional Removal of the Parchment Layer
Removing the Parchment Layer
Removing the Parchment Layer
Photo by Michael Burrows: https://www.pexels.com/photo/farmer-with-sieve-sorting-dry-coffee-beans-in-countryside-7125593/
Photo by Michael Burrows: https://www.pexels.com/photo/crop-farmers-with-bamboo-trays-sorting-dry-coffee-beans-7125592/

Hulling machines and equipment are designed to facilitate this delicate task while safeguarding the integrity of the beans. The machines gently separate the parchment from the beans without causing damage, ensuring they retain their inherent qualities and flavors. This precision-driven stage contributes to the overall quality of the coffee and enables the beans to reach their destination with utmost care.

With the removal of the parchment, the green coffee beans stand exposed—resplendent in their natural beauty and ready to reveal the rich palette of flavors cultivated through the journey of coffee processing. Each green bean carries the essence of its origins—the altitude, climate, soil, and the meticulous craftsmanship of the coffee producers.

Following hulling, the beans enter the final acts, which include sorting and grading. Green coffee beans are carefully sorted at this stage based on their size, density, and defects, ensuring uniformity within each lot. The sorting process facilitates a consistent roast profile and enhances the overall coffee experience for end consumers.

Sorting and Grading Green Coffee Beans
Sorting and Grading Green Coffee Beans
Image by Marcelo Toro from Pixabay - URL: https://pixabay.com/photos/coffee-toasted-green-grain-1129603/

Grading is the classification of green coffee beans into different categories, such as specialty grades, which represent the pinnacle of quality and unique flavor profiles, to standard grades suitable for various markets. This grading process allows coffee buyers and roasters to select beans that align with their preferences and intended roast styles, ensuring that each cup of coffee represents its origin.

Basket with Sorted Green Coffee Beans
Basket with Sorted Green Coffee Beans
Image by Marcelo Toro from Pixabay - URL: https://pixabay.com/photos/coffee-toasted-green-grain-1129600/

Once the green coffee beans have been hulled, sorted, and graded, they are ready to embark on their final voyage to consumer countries. They are packed in durable burlap bags, and these precious beans are symbols of the labor, dedication, and passion that coffee producers pour into their craft.

Bags with Green Coffee
Bags with Green Coffee
Image by April Rodmyre from Pixabay - URL: https://pixabay.com/photos/coffee-beans-espresso-raw-uncooked-625693/

As the green coffee beans cross borders and oceans, they carry the legacy of the lands they were nurtured on—a legacy etched into the very essence of each bean. From the sunlit coffee plantations to the hands of producers, the journey of coffee cherries through washed processing and hulling reveals its final act. This journey culminates in a delightful symphony of flavors, eagerly awaiting the skilled touch of coffee roasters.

Environmental Impact and Sustainability

Amidst the rich tapestry of coffee production, the threads of sustainability and environmental consciousness are interwoven, creating a story of resilience and stewardship.

Responsible Waste Disposal

At the heart of the sustainability conversation lies the responsible disposal of coffee pulp or coffee cherry husks, the by-product generated during the pulping stage. The environmental impact of improper pulp disposal must be considered. When left unmanaged, coffee pulp can become a potential threat to ecosystems. The rich organic material, if not processed responsibly, can lead to water pollution and disrupt the natural balance of surrounding environments.

Recognizing this potential ecological challenge, coffee producers have embraced innovative solutions to address the issue of pulp disposal. Rather than viewing the by-product as waste, they have tapped into its potential as a valuable resource. The coffee pulp can be repurposed as compost, enriching the soil and nurturing the coffee plants that bear future cherries. This sustainable practice fosters a cyclical relationship between coffee production and environmental conservation, where coffee cherries give birth to beans, and the pulp returns to the land to nourish the earth.

Moreover, coffee pulp can be utilized in other agricultural practices, reducing the demand for synthetic fertilizers and fostering a more eco-friendly approach to farming. The shift towards responsible pulp disposal mitigates environmental harm and elevates coffee farming to a more regenerative and sustainable practice.

Water Management

Water conservation and management emerge as pivotal considerations during the washing and drying stages of washed processing, particularly in regions facing water scarcity. Coffee-producing areas often grapple with the delicate balance of meeting their water needs while safeguarding precious natural resources. As coffee cherries are transformed into beans, efficient water use becomes an essential aspect of environmental responsibility.

Coffee producers are increasingly implementing sustainable water practices, such as recycling and reusing water during the washing stage. By carefully managing water resources, coffee producers reduce their overall water footprint, ensuring that local water sources are preserved for both agricultural needs and the well-being of nearby communities.

Certifications

Additionally, certifications for sustainability, such as Rainforest Alliance and Fair Trade, play a significant role in promoting responsible coffee production. These certifications impose strict environmental and social standards on coffee producers, encouraging transparent practices and ethically conscious decisions. For consumers, sustainability certifications offer reassurance that their coffee choices contribute to environmental protection and the well-being of coffee-growing communities.

Beyond the realm of environmental impact, sustainability in coffee production extends its embrace to the social sphere. Fair wages, ethical labor practices, and community development initiatives are integral to building a sustainable coffee supply chain. A commitment to fair and equitable treatment of coffee farmers and workers enriches the social fabric, ensuring that coffee beans' journey positively impacts the lives of those who nurture them.

In the symphony of washed (wet) processing, sustainability and environmental consciousness compose a harmonious note—a note that resonates with nature's rhythms and the aspirations of communities. Coffee producers, custodians of the land, uphold the vision of a thriving future where coffee cherries thrive on sustainable practices, and the delicate balance between growth and preservation is maintained.