In the coffee world, there are four (4) primary ways to process coffee. This is my attempt to give a super basic summary of each process, including what it means for the farmers, and for you and me when we enjoy the coffee in our homes, cafes, and offices. Each process begins when the farmers pick the ripe fruit from the coffee tree, often times called coffee cherries. Most of the time, ripe coffee cherries are red, but sometimes are orange or yellow in certain coffee varieties. If the coffee cherry is not ripe when picked, the overall taste of the coffee will negatively affected. After picking ripe cherries, the farmers then decide how they want to process them.
Pulp - The outer skin of the coffee fruit is removed with the help of a machine (pulper)
Hull/Parchment - The inner skin (or parchment) of the coffee fruit is removed with the help of a machine (huller)
Mucilage - The sticky remainder on the coffee bean from the fruit after the coffee cherry is pulped.
The following image will be helpful in understanding the coffee fruit or cherry. Also, Sweet Maria's has some great pictures of coffee beans on this page on their website.
1) First, there is a process called wet hulled (sometimes referred to as semi wash). This is primarily used on the Island of Sumatra where we source our Gayo coffee. Most other coffee producing countries don't use this process, or at least not as often. In the wet hulled process, picked coffee fruit is pulped and soaked in water overnight. The next day the beans are given a quick wash and then dried, followed by a trip through the huller while they still have a relatively high water moisture content. A little more drying and the beans are ready to sort.
Wet-hulled coffees tend to be known for their earthy taste in the cup, but this is primarily because of poor drying techniques (on the ground or close to the road). A well processed wet hulled/semi washed Sumatran coffee won't quite be on par with a fully washed Sumatran in many ways, but the process is a lot easier for the farmers, which means it can be processed more quickly, and consumers can get it for a cheaper price. Sweet Maria's has a good overview of a typical Sumatran coffee on this page of their website.
2) Washed coffees start out the same as semi-washed coffees, but after being pulped, the beans are soaked for 12 to 24 hours, with the water being changed ever 6 hours. This helps to remove the mucilage off of the coffee beans. The coffee beans are then washed and dried until they contain about 17% water content. Next they are placed through the huller and then dried again until ready to be sorted. You can watch a short video of some coffee beans being processed right after they are soaked here. Notice the amount of mucilage that Dul, one of the farmers, is removing. Dul does a great job processing coffee!
This is the main way farmers around the world process their coffee. More water is used than in the wet hulled process, and it is a bit more time intensive for the farmers. This is why the price for a Sumatran fully washed coffee will be slightly higher than that of wet-hulled. The coffee is also know for having a "clean" feel when you drink it, and giving a more consistent taste than natural or honey processes. The word on the street is that full washed coffees are easier to roast as well.
3) Natural processed coffees are not pulped or washed after being picked. Rather, the coffee cherries are dried right away until the outer skin dries up. This can take several weeks during the rainy season. After being dried, the coffee cherries go through the huller and are dried for a few more hours before being sorted. "Wine or Winey" coffee is a naturally processed coffee that has been allowed to ferment while being dried.
Being dried in the fruit gives the seed (coffee bean) time to absorb the unique flavors of the coffee fruit which can vary greatly among coffee varieties. This in turn, gives each naturally process coffee a unique flavor profile. Many people drinking Ethiopian naturals claim that there are flavors of strawberries and blueberries present. Sumatran naturals have a more "fruity" taste as well. While the farmers don't have to use any water for this type of process, it is the most time intensive, and the hardest to control, which results in a much higher price. For example, naturally processed coffees from Panama have been fetching extraordinary high prices for the past several years. You can read a great article about this here, and listen to a great podcast about this here from the I Brew My Own Coffee Podcast.
4) Lastly, there is a process called pulp natural, but more commonly known as honey process. It is a hybrid way to process the coffee. Like the washed coffees, the coffee fruit is pulped right away. After this however, the coffee beans are dried in the mucilage and not washed. The mucilage has a lot of natural sugars which is absorbed by the coffee bean. After it is dried, the beans go through the huller to remove the parchment and are then sorted.
In the cup, the honey processed coffees do tend to have a paring of sugar cane sweetness and tropical fruit, like a pineapple, with a lingering aftertaste. Price-wise, the honey processed coffees lie in between the washed and naturals, and like the naturals, are less consistent than washed coffees. Personally, I really enjoy drinking the honey processed coffees, and have found that the taste can get better over time.
If you want to get another perspective on coffee processes, you can check out a recent article from Forbes here. We would love to hear your feedback.