Coffee processing is the term given to a specific stage in the coffee journey in between harvest and export. We explain the different types of coffee processing that there are, why they are used, and how they can affect how your brew tastes.
Most coffee drinkers like to know what they’re brewing, not just coffee is inside the bag but also where it came from and how it got here. With speciality coffee roasters especially, the level of detail included on the bag label or on their website can be very detailed. Without prior knowledge or explanation, even experienced coffee drinkers can get confused by some of the terms. The processing method is one that can often crop up as the chief confuser. With that in mind, let’s look first at what processing actually means. Then, we can establish what different methods are used and how they affect the coffee we drink.
What is coffee processing?
We know that coffee is sold to us as a finished product that has been processed because it has been roasted. There are actually several processes involved in coffee production that take each take place at different stages. To help understand what they are and when they occur, it is helpful to remember coffee begins its journey as a cherry on the coffee plant.
Between harvesting the coffee cherries and them becoming the beans you see in your local shop or cafe, we need to remove all of the fleshy fruit and the moisture from the beans within them. There are a number of different processes we can use to do this, and each one will deliver a different end result that will affect the roast profile, brewing and the drinking experience. Now that we know what processing means, we can dig deeper into those different processing methods.
A lot of speciality coffees are washed which means that the cherry and its flesh have been completely removed before the beans were dried.
The process will usually begin with the cherries being dropped into deep baths of fresh water. This helps farm or mill staff to separate the good cherries from the bad ones because the bad ones (unripe) can be skimmed off of the surface while the good (ripe) will slope to the bottom. Mechanical screens are used to squash the cherries and remove most of the flesh, the rest (called mucilage) is then cleaned off using a process of fermentation (for around 24 hours) and then re-washing with more fresh water. The beans are then dried, usually on raise sun-beds with good air circulation around them.
The idea behind washed or wet processing is to deliver the coffee bean in its purest form. The flesh and mucilage can have an effect on the flavour that may detract from what’s happening inside the bean itself. With washed coffees, you tend to get a brighter and cleaner brew which makes it an ideal option for Colombian and African coffees that have high levels of acidity.
This is the oldest processing method in coffee. Naturals are a great topic of discussion in coffee circles as they can be incredibly divisive, think of them as the Marmite of the speciality coffee world! The reason being is that they produce really unique and strong flavours that some people find undesirable… and I’m one of them.
In natural processing, the cherries are picked and processed with the flesh still on the beans. The cherries are sorted as with wet processing, although this tends to be done by hand as opposed to floating at around origins who use dry processing. The drying takes place on nets raised above the ground, tables, beds or even just the patio where they are baked under the hot sun.
In dry processing, the drying is the crucial stage where the end result is really determined. The beans will be laid out for up to a month and therefore need to be turned manually using rakes to stop them from rotting. They also can’t dry too much as this will cause the beans to be brittle and prone to burning quickly during roasting. So this practice of rotating them is essential on two fronts. Once the beans have dried they are hulled which involves the dried flesh being removed using a special machine.
In places like Ethiopia, these steps can often take place in shared milling stations as part of a cooperative because the farmers often work on small plots and can’t afford to purchase the expensive equipment required for hulling. Most Brazilian arabica coffees are natural and the whole process will usually take place on the farmer’s own land.
Dry processing often results in a heavier mouthfeel with rich sweetness in the brew, which is why it really lends itself to the natural chocolatiness of a Brazilian or the juicy fruity notes in Ethiopian beans. Really strong examples of naturals may sometimes be described as funky or having fermented characteristics. Whether you grow to love them or loathe them, natural coffees are a must-try!
It’s probably not what you think it is, but it sure can be sweet! You may also see this written as ‘pulped-natural’ on the label or the menu in your local coffee shop.
In this process, the skin of the cherry is removed but the mucilage is left on for a period before for drying. The mucilage is only partially washed off so you can imagine this makes for a sticky process. The higher sugar content means fermentation can be fast so extra care is needed in keeping the beans rotating and giving them lots of air as well as heat. Once the beans are dried to around 10% moisture, the leftover parchment is removed and the green beans are ready to be sold.
Natural or semi-dry coffees can deliver a combination of characteristics from both natural and washed processes. You’ll find this process popular in Central America where the coffees are naturally, exotic, sweet and fruity in flavour. If you see a Costa Rican or Guatemalan that has been honey processed, be sure to give it a try.
After all of this, there are yet more processes involved before your coffee is bagged and sold to you. Even before it reaches the port the processed green coffee needs to be sorted, graded, sold and even polished before it is prepared for shipping.
We hope you enjoyed this brief introduction into coffee processing. You should now be able to read a label or description with confidence and know what to expect from your brew. As we always say, the best way to learn about the coffees you love is to try them all!