Beyond the Bean: Unpacking Myths of Washed vs. Natural Coffee Processing

Question: What are some common misconceptions about washed versus natural coffee processing?

The world of specialty coffee is rich with descriptors and processing methods that shape the final cup. Among the most fundamental are washed and natural processing. Yet, common understandings of these techniques often paint an incomplete picture, leading to misconceptions about the flavors they impart.

The ‘Cleanliness’ of Washed Coffee: A Nuanced View

A prevalent notion is that washed coffee, by definition, yields a “cleaner” cup. This stems from the process itself: coffee cherries are pulped, their mucilage is fermented, and then the beans are washed. This mechanical removal of the fruit pulp aims to isolate the inherent flavors of the bean, minimizing external influence [6]. Indeed, studies have indicated that initially, washed coffees might exhibit slightly higher overall scores compared to natural coffees, suggesting a perceived purity or refinement [6]. However, the fermentation stage within washed processing is critical. This controlled fermentation aims to break down the mucilage and can positively influence acidity and volatile compounds, contrasting with less controlled CO₂ treatments [3]. The goal is to reduce external fruit influence while enhancing the bean’s intrinsic qualities, which can lead to a brighter, more acidic profile when done well.

Natural Processing: More Than Just Fruitiness

Natural processing, where coffee cherries are dried whole with the fruit intact, is often associated with pronounced fruitiness and sweetness. The theory is that as the cherry dries around the bean, sugars and other flavor compounds from the fruit can permeate the bean. This method can indeed contribute to a range of flavors, from honey and spice to richer fruity notes, and even notes reminiscent of flowers or fruits [5, 6]. However, the extent of this fruitiness is not solely determined by the natural process. Varietals like the Catuai, known for potential sweetness and balanced acidity, can be processed naturally to enhance these characteristics [7]. Furthermore, the drying conditions are paramount. High drying temperatures, a parameter associated with natural processing, can significantly influence the final flavor profile [7]. It’s a delicate balance; improper drying can lead to defects rather than desirable sweetness.

Beyond the Basic Dichotomy: Interplay of Factors

It’s a common misconception to believe that washed coffee is always bright and clean, and natural coffee is always intensely fruity. The reality is far more intricate. Both processing methods involve fermentation, whether it’s to remove mucilage in washed coffee or as an inherent part of the drying process in natural coffee. The duration, temperature, and pH of these fermentations can dramatically alter the chemical composition and resulting flavors [3]. For instance, a prolonged or poorly controlled fermentation in either process can lead to undesirable off-flavors, undermining the perceived purity or fruitiness. Moreover, the bean itself plays a crucial role. Factors like growing altitude can influence flavor precursors, sensory characteristics, and the overall cupping quality of the bean long before processing even begins [4]. Even inherent bean properties, like the lipid content in Arabica beans, can influence foam stability in espresso, irrespective of processing [1]. The presence of compounds like amino acids, tribigonelline, and chlorogenic acid, found in both Arabica and Robusta coffees, are foundational flavor precursors influenced by origin and genetics, which processing then modifies [2].

Conclusion

While washed and natural processing represent distinct approaches to preparing coffee beans, their impact on flavor is a complex interplay of technique, environment, and the inherent qualities of the coffee cherry. Dismissing one as merely “clean” or the other as simply “fruity” overlooks the sophisticated science and artistry involved. Understanding these nuances allows for a deeper appreciation of the diverse and captivating spectrum of coffee flavors available to us.

References

[1] — Ernesto Illy, Luciano Navarini — Neglected Food Bubbles: The Espresso Coffee Foam. — 2011-Sep — https://pubmed.ncbi.nlm.nih.gov/21892345/ [2] — Magdalena Zdanowicz, Marta Rokosa, Magdalena Pieczykolan, Adrian Krzysztof Antosik, Katarzyna Skórczewska — Biocomposites Based on Wheat Flour with Urea-Based Eutectic Plasticizer and Spent Coffee Grounds: Preparation, Physicochemical Characterization, and Study of Their Influence on Plant Growth. — 2024-Mar-06 — https://pubmed.ncbi.nlm.nih.gov/38473683/ [3] — Gustavo Galarza, Jorge G Figueroa — Volatile Compound Characterization of Coffee ( — 2022-Mar-21 — https://pubmed.ncbi.nlm.nih.gov/35335365/ [4] — Rongsuo Hu, Fei Xu, Xiao Chen, Qinrui Kuang, Xingyuan Xiao, Wenjiang Dong — The Growing Altitude Influences the Flavor Precursors, Sensory Characteristics and Cupping Quality of the Pu’er Coffee Bean. — 2024-Nov-28 — https://pubmed.ncbi.nlm.nih.gov/39682914/ [5] — Rongsuo Hu, Fei Xu, Liyan Zhao, Wenjiang Dong, Xingyuan Xiao, Xiao Chen — Comparative Evaluation of Flavor and Sensory Quality of Coffee Pulp Wines. — 2024-Jun-27 — https://pubmed.ncbi.nlm.nih.gov/38999011/ [6] — Magdalena Zarebska, Natalia Stanek, Krzysztof Barabosz, Anna Jaszkiewicz, Renata Kulesza, Rafał Matejuk, Dariusz Andrzejewski, Łukasz Biłos, Artur Porada — Comparison of chemical compounds and their influence on the taste of coffee depending on green beans storage conditions. — 2022-Feb-17 — https://pubmed.ncbi.nlm.nih.gov/35177718/