From Sweet Maria’s travelogues , here are a set of images of how coffee wet processing is performed.
Wet-processing is still the preferred way to take arabica coffee cherry from the fruit to the bean / seed. Why is that? Let’s look at the history a bit and talk about “natural” processing first.
Dry Process versus Wet Process
Traditionally dry-processing was used in areas with no access to water, or areas where less care was put into the coffee due to low value. Dry-processing required less infrastructure, and was technically easy.
It made sense in areas with extended collector systems, where coffee was gathered in very small amounts from many farmers, the good blended with the bad. It was typically a rustic process that resulted in a rustic tasting cup. It makes sense in that light that dry-process coffee is still called “natural coffee” too.
Dry processing has changed in some ways, and we now have top-grade dry process coffee that requires careful effort to achieve a very intentional result. But in a sense this new wave of dry-processing
The Wet-Processing Advantage
Wet-processed coffee (also called washed coffee) was the traditional path to quality, for the very reason that it was more controlled and a better vehicle to achieve those intentional results: a uniform and clean tasting coffee.
Building a wet mill was more of an undertaking: It required land for a central processing station, aka a washing station, and access to a water source to run the mill and ferment the coffee. It required local infrastructure to get the coffee to the mill. It required skilled machine operators for the coffee pulper, and management to track the process. It required hired labor to perform the work, washing the coffee in the channel, delivering it to drying beds or patios etc.
One could make a good argument that the higher quality of good arabica coffee, it’s acidity and lower bitterness compared to robusta, could only be revealed with wet-process methods.
And that would be true, except that the care put into dry-processing now, and the costs to do it right, challenge the idea that fine coffee must be washed coffee
History of Coffee Process Systems
The kind of approach and investment, as well as centralization in the wet-process system harkens to colonialism in a sense. Or to the “hacienda” system that was usually owned by a nation’s elites, the landed class. Yet there was nothing intrinsically exploitative about the process. In fact, the systems that did the least to improve lives proved to be those resulting in low-grade commercial coffees, and those might be found more often in collector systems attached to natural coffee production.
As far as defining the process, the steps, the quality of the methods, you can find that repeated over and over in my travel videos, and other travelogues. I will leave it to the photos and captions to underscore the various approaches to creating a fine wet-process coffee! -Thompson
Wet-Process Coffee Method in Photos
The photo set roughly shows the process from coffee delivery and reception at the mill, sorting cherry, pulping off the skin, fermenting the coffee, washing it out of the fermentation tanks, initial sorting while wet, and while drying. All these steps aren’t done everywhere though… and I include a couple photos of pulpers that “machine wash” coffee so that it’s not fermented, like the Penagos machines.
I hope there is something you noticed about many of these images. I hope you noticed all the labor that goes into quality coffee, how much work it takes, and how we wouldn’t have fine coffee without all those people selecting the fruit, removing defects, washing the coffee etc etc. ! -Thompson