Washed, or wet-processed, coffee is a process that enhances the clarity and acidity of the flavors. This method, used primarily in Central America, Colombia, and East Africa, produces exceptional coffees with complex profiles, rich in lactic acid and enzymatic fermentation . These coffees are often characterized by a marked liveliness and fruity notes.
1. Selective Harvesting: An Essential First Step
The first step in producing exceptional coffee is the selective picking of coffee cherries. This must be done manually, thus ensuring that only the perfectly ripe cherries are harvested. This attention to quality during picking ensures that the coffee beans have optimal organic matter and better flavor profiles. Careful picking can improve the complexity of the coffee by 40% .
Statistic : According to a study conducted in Costa Rica, a well-executed harvest can increase the liveliness and clarity of the coffee, key factors in the fine aromas sought in quality coffees.
2. Pulping: Extraction of the Grain
After harvesting, the cherries are pulped using machines that remove their outer shell. Unlike natural coffee , where the shell is left on during drying, this process quickly exposes the beans to oxygen and prepares the microorganisms for fermentation .
Pulping plays a crucial role in optimizing the chemical reactions that will follow during fermentation, by allowing better control of the development of lactic bacteria responsible for aromas .
3. Controlled Fermentation: Decomposition of Mucilage
The coffee beans are then immersed in vats of water to begin a controlled fermentation process . This enzymatic fermentation breaks down the mucilage surrounding the beans. Depending on the fermentation time, the intensity of the aromas changes.
Fermentation data :
-
12 hours : Development of light aromas, with marked acidity.
-
24 hours : Best balance between acidity and sweetness.
-
48 hours : Aromas become more pronounced, but excessive fermentation time can lead to spontaneous fermentation and loss of freshness.
Statistic : Careful control of fermentation time improves the perception of fruity aromas by 30% . However, high or low temperatures can disrupt chemical reactions and affect the quality of the coffee.
4. Washing and Rinsing: Removing Residues
Once fermentation is complete, the beans are washed with clean water to remove all traces of mucilage. This washing step ensures a clean final product free of residue that could alter the coffee's flavor. It prepares the beans for the next drying phase, where preserving the bean's aromas and texture becomes essential.
5. Drying: A Decisive Phase
Drying is crucial for stabilizing the beans and reducing their moisture content to around 10-12%, allowing for better preservation and flavor extraction during roasting. The type of drying used often depends on local climatic conditions, but the most common methods are raised African beds and mechanical dryers.
-
Raised African Beds : Drying is done in the open air, with good air circulation to prevent mold and ensure optimal room temperature .
-
Mechanical dryers : These machines allow precise humidity control and are often used in more humid environments.
Statistic : A study conducted in Brazil found that drying too quickly could alter the floral notes of coffee, while drying too slowly promoted unwanted fermentation . Optimal drying control avoids organic waste and maintains the quality of the final product.
Variations in the Washing Process
Some farms are experimenting with variations of the washing process to achieve different flavor profiles and reduce the environmental impact of their production. Innovative techniques include:
-
Anaerobic fermentation : The beans are placed in an oxygen-free environment to promote more intense aromas. This process alters the chemical reactions that occur during fermentation, leading to coffees with more fermented and complex aromas.
-
Eco-friendly process : Some farms are adopting eco-friendly washing methods that use less water and produce less carbon dioxide . For example, water recycling systems help reduce the environmental footprint by minimizing organic waste.
Conclusion
The washing process is a science that relies on a precise balance between lactic acid bacteria , microorganisms , and environmental conditions. Each step, from harvesting to fermentation and then drying , is crucial to obtain an exceptional coffee. Optimal control of fermentation time and drying is essential to maintain the integrity of the aromas and produce a pure, balanced coffee appreciated by coffee lovers around the world.
