Natural Vs. Washed: The main coffee processing methods you should know
Have you ever wondered what does "processing method" mean when you see it on a bag of coffee? Do you even need to know this information? Well, probably yes!
Processing method is one of the major factors that forms the tasting notes in your cup. You can imagine the flavors and sensations you get from the coffee before you even brew it. There are an increasing number of methods to process green coffee but today I am going to guide you through the most common ones: natural and washed.
So what is coffee processing?
After growing and harvesting (ideally only the ripe cherries), the coffee needs to be treated in different ways (depending on the purpose, location and condition) to separate the cherry flesh and the beans and before they are packed and shipped to any roastery. The final green coffee bean has to be dry while keeping a certain amount of moisture (10-12% for specialty coffee) inside the bean for optimal storage and roasting. This processing step is crucial as it requires great time and effort of the producers to create the best possible raw ingredients for the cup of coffee you will be enjoying. A careless mistake can ruin a lot of good coffees, which take months if not years to grow and be ready for harvesting.
"Ok tell me about the methods then!"
1. Natural or dry method
This is by far the oldest and the most traditional method. After the harvest, coffees are dried in full cherry on a raised bed with small holes to increase airflow, which leads to more even drying. This way, the coffee bean and flesh are in contact for a longer period, which means the sugars, fruitiness from the coffee cherry can be absorbed into the bean during the stage of drying, creating the unique flavors of natural processed coffee. However, due to this prolonged contact time between the bean and its cherry, there is a big risk in overfermentation and mold development that carries a overwhelmingly funky notes and flavor defects. Therefore, producers have to be very careful here and ensuring the coffees are turned regularly during drying to avoid those risks. After drying, everything goes into a machine for de-pulping, which means separating the dried cherries and the green coffee beans. This processing method is commonly practiced in Brasil and Ethiopia, where the water supply is insufficient.
2. Washed or wet method
This is the main way of processing coffee nowadays, meaning most of the coffees you find out there have gone through this method. In contrast to the natural method, the coffees are going into the de-pulper machine right after harvest to remove the coffee flesh and skin from the bean. However, there is still a thin layer of mucilage wrapped around each bean at this stage. To remove the mucilage, the beans then go into a tank to do a little bit of fermentation. I said "a little bit" but it can vary greatly between 12 and 72 hours. After this stage, the beans are washed thoroughly with clean water and finally going to bed. I mean they are placed on raised beds or patios for drying purpose, but it sounds similar to you taking a shower before going to sleep, roughly speaking. Anyway, this method is considered safer as it is more consistent and contain lower risk of defects. The trade-off is that it uses a lot of water, therefore more expensive to produce.
"I can see the differences between the methods now, but how does this impact the taste?"
There is a tremendous difference in cup profile since the coffee bean is dried on its own in one method and dried within full cherry in another:
- Natural coffee is a combination of flavors from the bean and the fruit. Thus, the cup profile is often more intense and vibrant with a heavier body. You also can find more sweetness, berry or tropical fruit notes and some winey characteristics in natural coffees.
- Washed coffee is all about the flavors of the bean itself. The coffee of this kind tends to produce a clean, bright and lighter body profile. Your overall cup experience will be more soft and balance with somewhat clearer fruity and floral notes, meaning they are easier to pin-point.
One extra tip to differentiate natural to washed coffee just by looking at the bean. When you look at the roasted coffee bean, the center line of a natural coffee is usually dark due to more sugar content in this kind of coffee. Meanwhile, the same line in a washed coffee has a noticeably lighter color. See the photo below for comparison.
I hope this week's blog post helps you find the differences between the two most common processing methods in coffee. Have you tried both of them? Which one do you prefer?
- Long Nguyen -