Developers and Coffee — Part 2: Processing

Let’s say you’re sitting in a coffee shop, enjoying your perfect cup of an Ethiopian brew. Have you ever wondered what happened to those beans before they were ground and brewed for you? How did they grow, and what was their journey before ending up in your cup?

As you may know from my previous post in this series there are a lot of components that influence the quality of coffees that you drink. Starting, of course, with the bean itself. Did you know, that there are over 40 varieties of Arabica alone? Different varieties are of course cultivated in different parts of the world, and it greatly influences taste and aroma. Let’s say you’re drinking a wonderful Ethiopian Yirgacheffe (it’s a varietal name that comes from an Ethiopian district name). What are the other components that influence the taste?

There are two major processes that take place between coffee growth and brewing that are crucial to the final taste. They are: processing and roasting.

Coffee washing

Today, let’s talk about processing. What is it? What does it do to the beans, and how does it influence the final cup? Just after picking, coffee cherries need to be processed. It’s a process of removing the coffee pulp and mucilage from the fruit, in order to take the (two) beans out. There are two major ways to process coffee cherries.

Dry Processing

Dry processing (also known as unwashed or natural coffee) is considered to be the easier and cheaper processing. It’s also the oldest method. In this process entire coffee cherries are first cleaned after the harvest and then placed in the sun on tables or patios. The cherries are left to dry there for up to 4 weeks, until they are dried to the optimum moisture level. As the cherries dry, they are raked or turned by hand to ensure even drying and prevent mildew.

Dry processing in Panama (source: Wikipedia)

This method is used with about 90% of Arabicas from Brazil, as well as some coffees from Ethiopia and India. On the other hand (since dry processing is considerably cheaper and easier than wet processing), all Robustas are processed this way.

Dry processing leaves the beans with a very characteristic “dry processing” flavour. It’s known to make coffee a little sweeter and much heavier in taste. On the other hand, coffees processed in this natural way are much less clean and bright, and get some earthy qualities from the processing. Sometimes this could come of as strawberries or blueberries (I’ll never forget the best dry processed coffee that I’ve had: Ethiopia Jirmiwachu Natural by Square Mile).

Wet Processing

There is a dry process, so there has to be a wet one as well :) And there is! This method is considerably more expensive since it requires substantial amount of fresh water. Coffee processed this way is called wet processed or washed coffee.

This process is started with sorting by immersion in water. Bad and unripe cherries would float on the surface, while good ones sink. Then the skin of the cherry, as well as some of the pulp are removed by machine pressing the berries in water. The beans are left with a significant amount of pulp that still needs to be removed. This is usually done by fermetnation. Cherries are left in the water until all pulp is fermented, and then washed in large amounts of fresh water. After that, all washed beans are dried in the sun and ready to be shipped to roasters all over the world.

Washed coffees are considered to be higher quality. There are no “processing flavours” left in the beans (like the earthy quality after dry processing). It makes the coffee very clean and bright in flavor, enabling rich aromas to develop.

The last processing method is called semi-dry. This process is a hybrid, which is sometimes called pulp-natural. It reduces the acidity and increases the body, which is sometimes desirable in coffees from Brasil (where this method is mostly used). There are some more variations of hybrid methods (ie honey process) that are very region-dependent.

What’s in it for you?

Next time you enjoy your filter coffee, take some time to consider the long journey that those beens have taken before ending up in your cup. Ask your barista about the way your coffee had been processed before it was brewed — they’ll know the answer if they’re really into coffee ☕️💪

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