Natural vs. Washed Coffees

Griff Thomas

Wed Feb 05

By Reiko Piekarski

Director of Coffee

Complexity in a brewed cup is determined by a number of contributing factors. There are environmental impacts that are completely out of the producer’s control, but there are also human influences that can unlock the nuanced characteristics deep within the seed. One of the biggest impacts on the final brewed product is the processing method applied once the coffee is harvested.

Determining the Best Method

Geographic location, weather conditions and access to water are some of the main factors considered when determining what processing method to use. Before coffee can be exported it must dry to a stable 11-13% moisture content to prevent spoilage. In wetter climates, the coffee needs to dry faster so processing involving a quicker drying time is more desired. For some areas, water can be scarce which warrants a method that does not tap into fresh water sources. Wet mills can be costly and inaccessible to smaller producers as well. It all boils down to two distinguishable methods commonly practiced in the coffee industry; natural and washed processes.

Washed Processing

Most of the world’s coffee production has adapted to using the washing method. Wet mill processing was first developed in Costa Rica and is now the most common processing method used across Central and South America. Once the coffee cherries are picked and sorted they are poured into a de-pulping machine that separates the seeds from the skin and fruit. The de-pulped seeds will still have a sticky layer of fruit which is removed by allowing the coffee to sit in a fermentation tank with fresh, clean water. With careful monitoring over a 12-72 hours period, the sticky mucilage will loosen and dissolve. The seeds are rinsed off with fresh water before they are laid out to dry. It takes 7-15 days for the coffee to dry on patios, rooftops or raised beds. The washed method is utilized in wetter climates because of the accessibility of fresh water and the large amount necessary for removing all the fruit from the seed which shortens the drying time. Washed coffees typically present clean, sweet and balanced cups. Longer fermentation times develop more complexity, fruity and savory qualities. However, if coffee is left fermenting too long the batch will be ruined.

Natural Processing

Natural or dry processing was the original method used for centuries before the introduction of wet mills for washed processing. In this method, the ripe coffee cherries are harvested, sorted and laid out to dry on raised beds. No de-pulping or washing of the coffee is involved thus conserving on the scarce fresh water supply. The fruit is not separated from the coffee seeds until completely dried when it is much easier to remove by hand or machine. The drying takes several weeks depending on the climate. To prevent uneven drying and mold growth the fruit must be turned throughout the drying stages which is labor-intensive. Since the skin and fruit are left on the seed the coffee develops a distinguished berry fruit characteristic that is round and complex. Until several years ago coffee produced using the natural method was considered defective due to the intensity of flavor. This processing method is ideal for drier climates and lower elevations.

Conclusion

Experiencing coffee processed through various methods is similar to exploring different beer styles. There are certain characteristics developed depending on how and what is applied in the production line. Whether it is beer or coffee there is a spectrum of possibilities for unlocking flavor. It is important to explore these various methods not only to understand differences but also to discover something new. These experiences are what shape and develop our taste preferences so receive them with an open mind the next time you come across unfamiliar grounds. One never knows when they might find their new favorite brew.