The Different Ways of Processing and Drying Coffee
Coffee plants produce both coffee flowers and coffee cherries.
Welcome back guys! In our latest post, we’re taking a closer look at the different ways of processing and drying coffee!
Coffee beans as we know them are the seeds to these coffee cherries. Before a coffee bean can be roasted, it must first be removed from its flesh. This is known as processing. This can include things such as removing layers of skin, pulp, mucilage and parchment which surround the bean.
When looking at the different ways of processing and drying coffee, we must first note that there are three main ways coffee is processed around the world. These are known as Washed processing, Honey processing and Natural processing. There are many things farmers have to take into consideration before they decide how they are going to process their coffee beans; for instance, the scarcity of water available.
The washed process involves removing the flesh that surrounds the bean using water. This type of processing is very dependant on the beans absorbing enough natural sugars and nutrients during growth. Factors such as the varietal, soil and weather are key to this.
Once the cherries have been picked, they are put through a depulping machine. This removes the outer skin and the majority of the fruit’s flesh. The cherries are then set into a fermentation tank where any remaining flesh is removed by the fermentation process.
The amount of time the cherries are left in the fermentation tank is dependant on things such as altitude and temperature. The higher the temperature, the less time the beans spend in the tank. If the beans spend too long fermenting, this can create unwanted flavours. Generally, the beans will spend between 12-24 hours in the fermentation tank, but this will vary as mentioned above.
There isn’t a set amount of water to be used for the fermentation process; this differs from farm to farm.
After processing, washed processed coffee beans are dried, as mentioned below.
This method of processing coffee is a variation of the pulped natural method. The pulped natural process originated in Brazil.
The pulped natural process removes the skin and most of the mucilage. However, rather than being washed to eradicate the remaining mucilage, they are dried on patios. This process can create a much sweeter cup with a full body.
Some Central American countries such as El Salvador and Costa Rica use their own version of this, known as the honey process.
As before, the cherries are depulped to remove skin and mucilage. However, this is done in a controlled way to determine exactly how much mucilage is left on the bean. This controlled method gives the opportunity for lots of flavour profiles to be created.
As a result of mucilage being left on the beans, they are more susceptible to mould growth and defects. To tackle this, the beans are regularly turned and protected from insect damage while drying.
You may have come across some terms such as ‘yellow honey process’ or ‘Perla Negra’. These terms are used to describe either how long the beans spent in the cherry before being depulped, or the amount of mucilage left on the beans before they are dried.
This method of processing coffee is the oldest and most traditional way of coffee processing. You will find most naturally processed coffees come from countries that don’t get much rainfall, such as Brazil and Ethiopia.
Unlike the washed and honey process, the cherry is left entirely untouched after harvesting. Instead, natural coffees are left on either brick patios or special raised drying beds.
Once the coffee has adequately dried, the outer husk of skin and dried flesh are mechanically removed before it is then sent out across the world. Although this sounds like a pretty simple process, the climate has to be perfect to ensure the fruit dries correctly.
When looking at the different ways of processing and drying coffee, and as new processes and methods have been introduced, the natural process has taken a step back and is now considered to produce lower quality coffees. Its inconsistency can often lead to unripe fruit hiding within the ripe fruit.
However, many believe that as the natural process becomes more consistent, it will produce some interesting and unique tasting coffees. It is also believed that the natural processing method will more than match up to the honey and washing processes.
Depending on how the coffee bean was processed and where it was processed, the way it is then dried can vary.
When coffee is dried, a moisture meter is used to measure the moisture level residing in the coffee bean. The moisture content must be brought down from 60% to around 10-12%.
Similar to how coffee is processed using the natural process, the coffee is placed on brick patios or raised drying beds and is turned regularly to ensure slow and even drying.
When an area doesn’t receive enough sunshine or the correct humidity level, the beans can be dried in mechanical dryers. Generally, coffee that has been sun-dried rather than mechanically dried is seen to be of better quality.
Research has been compiled which suggests that drying coffee very slowly and evenly on patios rather than in dryers can improve the quality of a coffee, as well as improving how long a coffee retains its flavours while in its raw state.
When coffee is mechanically dried, the dryer should never be above 40-45 Degrees Celsius. At higher temperatures, the potential flavours of the coffee will be completely ruined. At extreme temperatures, the beans will crystalise and if dropped or smashed, will break like glass.
A further method of drying coffee is solar drying. This way of drying coffee is a lot more environmentally and economically friendly than a traditional mechanical dryer as it doesn’t use any fossil fuels or electricity. Due to solar dryers producing a much higher drying temperature, the beans will dry a lot quicker. However, as mentioned before this may not necessarily be a good thing.
Having now looked at different ways of processing and drying coffee, when you next choose your coffees from us, look in the ‘Nuts and Bolts’ section of each coffee to find their processing methods. Enjoy.
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