With striking similarity to wine, coffee has a seemingly endless variety in tastes, mouthfeel, aromas, nuances, acidity levels, etc. And, just as with wine, every step of the process, from seed to cup, impacts the way the coffee is experienced. One of the most influential steps is processing the harvested coffee cherries into dried green coffee beans, ready for roasting.
Dry process coffee cherries
The most popular methods, on either end of the spectrum, are washed and dry (natural).
Washed process can be thought of as the purist's preferred method because the coffee cherry is washed off of the bean immediately after harvest. The coffee processed in this manner allows you to strictly experience the nuances that are imparted to the bean only. The innate qualities of that particular varietal, the soil in which it was grown, the ripeness, each reflecting their true character in the cup. You may hear people refer to coffee processed in this manner as having a "clean finish," meaning the body doesn't linger on the palate.
Dry or Natural process, the coffee cherry is allowed to dry on the bean. As the cherry ferments, it imparts its sweetness and fruit notes to the coffee that are still prominent even after roasting.This is considered the oldest method of processing coffee, but it can be wildly inconsistent if not properly tended. Since it requires more effort, these coffees can be a little pricier, but the amazing flavors that can be achieved make it a worthwhile indulgence.
Now that the opposing ends have been established, let's touch on some of the in-betweeners. Here are a couple of other processing methods you'll most likely come across: Semi-washed and Honey.
Semi-washed process means that most of the mucilage is removed, but a little is allowed to remain. As the name implies, water is used during the de-pulping stage. This process is used in Sumatra, and is also known as "wet-hulled" coffee.
Because Sumatra has such a humid climate, this method was devised to facilitate the drying process much quicker than other drying methods. The outer skin is first removed with machines. Then, the coffee beans, including the mucilage, are stored overnight to allow them to ferment. This helps pectin break down the mucilage, making the next step a little easier.
Then, the beans are washed, removing the mucilage, and they are left to dry for a few days in the sun. This is done specifically to allow the parchment to dry a bit in preparation for the next step.
Since the beans, themselves, are still very far from dry, the parchment clings to the bean. They are put through a specially designed hulling machine that provides a little extra friction, helping the parchment release.
The result is a deliciously full-bodied, somewhat earthy cup of coffee with very little acidity. For a more in-depth account of this process, click here.
Honey process (or pulped natural process) leaves much of the mucilage intact, with the outer skin removed. However, unlike the humid climate of Sumatra, this process is mostly used in areas with generally low humidity.
Attentive and regular turning of the beans is required, allowing the mucilage to dry relatively quickly to avoid risk of mildew. There are a few subcategories of honey process.
" White honey" refers to the least amount of mucilage left on the bean to dry, and is the first to fully dry.
" Yellow honey" has very little mucilage left on the beans.
" Red honey" and "Black honey" are processes that slow the drying time by increasing the shade and humidity the beans are exposed to, with black honey taking the longest time.
This is a labor intensive process, but the result is a coffee that is lively and clean (as in wash processed) and yet has a full body with natural sweetness (as in dry processed). Delicious!
While most of our coffees at ACR are wash processed, we do offer a few dry processed coffees. Ethiopia Mocha Harrar, Bali Kinatamani, and Midnight Kiss Natural French are some of our mainstays, but keep an eye on out. Sometimes they appear in our Limited Edition Series or as a Roaster's Choice showcase as well.
Up for some home experimentation? Try our Spirit Mountain Washed against our Spirit Mountain Red Honey. They're both amazing coffees on their own but comparing these side by side demonstrates the dramatic difference in taste that can be achieved between these two processes.
Still haven't had enough? Take a look at an article about our latest Roaster's Choice offering for details about another process that's been gaining momentum in the coffee industry- Anaerobic fermentation/Carbonic maceration. This is a whole other level of geeky!