Coffee’s taste is not only affected by the region it comes from or the cultivar, but also by how it is processed. The coffee bean can be processed in one of two ways: natural (dry) processing or washed (wet) processing.
The way coffee is processed (natural or washed) affects its flavor and mouthfeel. So, if you want a certain type of coffee, you should know how it was processed.
There are many variations of these two methods that allow producer groups and farmers to showcase their coffee artistry.
When you’re searching for the perfect cup of coffee, you never know where you’ll find it because coffee flavors can vary so dramatically.
It is important to understand how coffee beans are processed in order to know which flavors they are likely to have. This is similar to knowing the different types of coffee plants and where they are grown.
The basics of coffee processing
1. Washed process
The method of extracting the seed (bean) from the coffee cherry by wet processing is a modern coffee processing method. The coffee plant first grew in areas near springs where water was plentiful.
Its popularity spread because it produced a clean tasting coffee. There are several wet process methods used today, but the most common ones share some key features.
Since it is best to only harvest ripe coffee cherries, usually a second quality check is needed. There are two approaches here. Either a group of harvested coffee cherries are covered in water, and only those that sink are de-pulped.
are skimmed off One way to process cherries is to remove the pulp with water, leaving the pips and pulp that sink. The floating pulp is then skimmed off.
The floaters are considered unripe or damaged, while those that sink are of a higher quality. Some countries (like Colombia) will either use dry-processing for their coffee beans that are floated, or use it for local or commercial consumption.
Both of these qualities may then be covered in water and fermented without air in some countries. The mixture of the pip and the mucilage is washed again.
In order for coffee to be processed, it must either occur in long washing channels or in a separate washing container. Washed coffee is coffee that has been cleaned with water. The coffee is then dried until it reaches the desired moisture level, which varies depending on the country.
2. Natural or dry process
The natural processing method is most likely the oldest processing method when it comes to coffee. The whole coffee cherry or fruit is used during the process.
The cherries are sorted by color after they are picked. For cultivars that are red, only red cherries are used, yellow only yellow and orange only orange.
At this point one of three things happens. Ripe cherries are spread out:
- on either a flat surface like a roof, a patio or plastic sheeting or
- over raised beds, or trays and left in the sun or
- over a shaded raised beds or trays.
After this, the methodology used effects the final taste. If cherries are left to dry without being taken care of, they will start to rot. Coffee cherries ferments quicker when it is at the bottom of the pile.
Careful farmers, producers, and processors will regularly turn or mix their cherries to prevent fermentation from ruining the coffee’s flavor.
Cherries that are natural and of the best quality should be thrown or rotated at least once every two hours in order to maintain uniform dryness. This practice will also prevent the natural fermentation process from affecting the taste of the coffee.
The cherry is removed from the drying area when the internal moisture level is between 20-30%. The cherry is then bathed in a mechanical dryer at just over 30 °C. The moisture level is removed from the dryer when it is between 10 and 12%.
It’s better if the coffee dries out naturally. When it reaches an internal moisture level of 10-12%, it should be removed from the drying bed or patio.
A well-processed natural coffee will be sweet and juicy, like the Gishubi (or Gitwe) coffee we offer, or the new Yemeni coffee that will be offered as part of the secret offering this month. If a natural is not properly processed, it will become dusty or funky in taste.
We believe that you should be the judge of whether or not natural coffees can produce a clean and quality cup.
3. Honey process
Vegetation and water are used in natural processing, while only water is used in wet processing. Natural processing allows natural drying of coffee cherries.
Pitting the coffee cherry exposes the bean inside while using the fruit’s natural fermentation. The coffee is first washed to remove the fruit, then the remaining pulp is fermented away from the pip underwater.
The honey process is a method of processing coffee beans that can also be called pulp-natural or semi-natural. Honey processed coffee generally refers to smaller batches of coffee that have been dried in the sun.
Pulp-natural coffees are large commercial lots that are first dried in the sun and then often completed in an automated drier.
The honey-processing of coffee was developed as a way to speed up the drying process. If you remove the skin from the fruit pulp it will dry sooner. Getting coffee to market quicker was the objective.
Water-scarce areas were initially only able to produce honey-processed coffees. The interesting cup-quality and flavor notes of these coffees promoted the method to other areas.
Coffees that are processed using honey use machines that are set to remove the skin and some of the fruit pulp from the coffee beans.
Black, red, yellow and white
It has become common that there are difference names associated to honeys.:
- Sometimes this is linked to the amount of mucilage removed. With black, red, yellow and white honeys removing more of the mucilage. Each level producing a different name with black the most pulp and white the least.
- Other times it is linked to the drying times for each honey processed coffee, with black being the longest and white the shortest. Perhaps the fact that the more pulp there is the longer the coffee will take to dry explains this.
- Also we have heard the terms associated to how long the pulp has already spent drying. Here white is new and black is almost ready.
As you can see there is no clear definition. When you read descriptions of wine, be aware that they are linked to the final taste.
Back to honey processing. The sticky fruit that remains after the pulp is removed is laid out on a patio or raised beds. The fruit pulp is then fermented and tossed regularly for well-processed honeys.
The coffee seed is removed from the drying table or patio when the desired moisture level of 10-12% is achieved. The same processing that occurs with natural numbers also occurs with these numbers.
4. Wet hulling
Wet-hulling likely originated with the Dutch after they acquired the coffee plant from India and colonized Indonesia in the 1700s. The coffee plantations in Europe were established in Java. That is why coffee is linked to java.
We need to explain what hulling, or milling, is before we go further. Hulling is the process of removing anything that is not the pip from the plants produce. There are several methods of hulling, depending on the type of plant produce.
These grains have a husk around them that needs to be removed. This is usually done by hitting the grain (thrashing) or rubbing it. To roast coffee, the parchment—or protective layer—needs to be removed.
The bottom layer is called the silver skin and is usually only removed after roasting. I wrapped it tightly around the pit. During the roasting process, the silver skin is typically shed as the coffee bean expands.
Wet-hulling coffee is a method used mainly in Indonesian countries. This method is believed to produce coffees with dominant spicy notes, which is characteristic of many coffees from this region. Indonesian coffees that are brewed using the methods we have previously covered are now available.
This method results in cleaner and sweeter coffee. Our current Indonesian Kerinci coffee is an example of this. Although the primary flavor is not spicy, we can still taste the spiciness.
5. Grading
The quality of the coffee is determined by the defects in the coffee beans. The coffee beans are graded according to the severity of the defects.
The Specialty Coffee Association has developed a coffee grading system called the “Green Arabica Coffee Classification System” that can be used widely.
They have described the number of defects and imperfections that can affect the quality of coffee. There are two types of defects in coffee beans, primary and secondary. They are measured in a 350-gram coffee sample.
Primary defect
When the coffee beans are over-fermented, or have been mixed with organic matter.
Secondary defect
When there are insect-damaged or broken beans.
There are 5 grades of coffee, with Grade 1 being specialty coffee and Grade 2 being premium coffee. The SCAA only cares about the top two grades out of the five. Grade 3 (Exchange Coffee), Grade 4 (Below Standard Grade Coffee), and Grade 5 (Off-Grade Coffee) have many defects and lack the flavor of the coffee consumers are familiar with.Grade 1 (Specialty Coffee) – 0-3 full defects, no primary defects, and sorted with a maximum of 5% above or below specified screen size. The coffee bean exhibits a distinct attribute in one or several of the following areas: aroma, body, acidity, or taste. The moisture level is 9-13%, there are no cup taints or faults, and no quakers.
Grade 1 coffee has no more than 8 full defects, and no more than 3 quakers.
Grade 3 coffee beans are those that are 50% above the average size and no more than 5% below the average size. Must have no more than 9-23 full defects, and a maximum of 5 quakers.
Grade 4 (Below Standard Coffee) – 24-86 full defects.
This coffee would be considered more than 86 full defects and would not be able to be sold as anything other than off-grade coffee.
6. Screening
In order to ensure that coffee beans are a consistent size, they must undergo a process of screening. Coffee beans are sorted by size through a process called screening. Screening allows producers and farmers to determine which beans are usable and which are not.
The coffee beans are sifted through metal sheets with specifically-sized holes. The screens are numbered according to how many 64ths of an inch the holes are. For example, a screen with 8 holes per inch would be referred to as a “8 screen”, while a screen with 20 holes per inch would be referred to as a “20 screen”.
For example, a size 10 screen has holes that are 10/64-inch wide, while a size 18 screen has holes that are 18/64-inch wide.
The size of a coffee bean selection is determined by the beans passing through smaller and smaller screens until they are the desired size. The coffee beans are graded according to the size of the screen they pass through. For example, if the beans pass through a size 16 screen but not a size 14, they would be graded as size 16.
Although the measurements are not always perfect, smaller and larger beans are usually given some leniency. The usual practice is to use even-numbered screens for Arabicas and odd-numbered screens for Robusta varieties.
An Arabica lot graded at screen size 18 is often 17/18 because the next smallest screen used for it is size 16.
Conveying coffee beans within a processing facility
The conveyor is one of the key pieces of coffee processing, and choosing the right one is crucial.
Many producers and farmers want a conveyor system that is dependable, clean, efficient, and quiet so that it can move the coffee through each stage of production and packaging without much breakage and no contamination.
Tubular cable and disc conveyors are the best choice for conveying coffee because they gradually move the coffee beans through an enclosed tube.
The process of roasting coffee beans does not damage the product, which is crucial because dry coffee beans are very fragile. Also, it is hygienic and easy to clean.
Since the tubular drag conveyor moves ground and roast coffee through an enclosed tube, it eliminates product degradation and separation that occurs within traditional conveyors.
Layouts can be customized with multiple inlets and discharge points to customer specifications.
The future of coffee processing
The coffee-producing countries that have a long history of coffee production always prefer a specific process. For example, regions like Korea and Taiwan that have long traditions of eating fermented and pickled food will often favor naturals.
The washed process is most commonly used in Central and South America because it is the most consistent method for producing high-quality coffee.
Due to the recent rise in popularity for specialty coffee, things are starting to change. Climate and environmental factors are increasingly motivating farmers to explore different processing methods.
In Rwanda, Guatemala, and Nicaragua, some producer groups and farmers are turning to producing honey and using natural processes, which allows them to create new flavor profiles that coffee aficionados may find unique and unusual, adding more value to the farmer’s crop.
Farmers are innovating in the coffee industry by changing more than just the processing method.
Some of them are trying to find the best catalyst to speed up fermentation, while others are experimenting with the absence of oxygen (during fermentation). Some are trying to find the best catalyst to speed up fermentation, while others are experimenting with the absence of oxygen (during fermentation). Coffee profiles are being created through knowledge-sharing and new technology.
Although it is not widely publicized, coffee processing plays a key role in determining the flavor of a cup of coffee.
An experienced team at Cablevey know that coffee breakage is a big issue for coffee producers, especially when transporting roasted coffee beans (which are fragile and prone to damage).
The design of our tubular cable and disc systems makes them flexible and enclosed, which is important in preventing contamination and ensuring traceability.
If you want to deliver high-quality coffee beans to your consumers, you need to add consistent hygiene, low energy consumption, and easy maintenance to your coffee beans.