Coffee travels a long way from fruit ripening to brewing. It is during this way that beans get their distinctive taste and aroma. These characteristics are significantly influenced by the method of coffee processing. Even in case of a good harvest and a perfect cherry-picking of ripe coffee berries, poor processing can mess up the whole business and lead to significant defects and changes in taste that, in the end, will reduce coffee value.
The processing method can so strongly affect the taste of a future drink that roasters and baristas are currently mentioning it with increasing frequency when describing coffee characteristics.
Coffee bean is nothing more than that seed inside a coffee berry. And coffee processing is nothing more than the process of extracting this very seed from the berry. Yep, a piece of cake!
The main methods that are used in coffee industry are natural and washed processing (but there are also some of their varieties and alternative methods). So, let’s talk about the natural process
Natural processing (also known as dry, unwashed or sundried processing) derives its name from its own essence — only natural processes take place in this case. This method means that freshly picked berries are left to dry in the open air for several weeks without any preliminary processing. Berries are scattered forming a thin layer on a special surface and everything is in the bag :).
In fact, the same thing happened with berries in nature even before human intervention: they became ripe, fell to the ground, their peel and pulp dried and decomposed leaving only coffee beans. Then people adopted the same way of coffee processing, which is why it is considered to be the most ancient and classic method.
Before drying, it is necessary to carefully select ripe berries from overripe and unripe ones, as the former can spoil the taste of future coffee and the latter darken while drying and become indistinguishable from ripe berries, which can also negatively affect taste characteristics.
The main task in natural processing is to dry berries evenly and prevent them from rotting, in this regard, the layer of coffee berries should be as thin as possible and berries themselves need to be raked and turned quite often throughout the day (at least every 6 hours).
Coffee berries can be dried on various surfaces (called ‘stations’), depending on the geographical region or the farm itself. Most often, palm leaves, concrete or clay platforms (known as ‘patios’), special coasters with a net (known as ‘African beds’ — from the place of invention) are used for these purposes.
Some farmers dry berries directly on the ground (the earth is a great moisture absorber), but in this case, coffee can acquire an undesirable earthy odor.
A lot of chemical reactions take place in coffee beans during sundried processing: along with the evaporation of liquid, a parallel process takes place as well — beans are exposed to the impact of different substances from pulp, which eventually greatly affect coffee taste and aroma.
One of the main substances that has this crucial effect on the taste of a future drink is sugar. Different fermentation processes occur in berries while they are being dried, and sugar penetrates from pulp into the beans. It is for this reason that naturally processed coffee is very sweet, fruity and flavourful.
As soon as the drying process is completed, only 11-12% of moisture remains in the fruit, its peel becomes dark-brown, very dry and fragile, and the bean itself is freely located inside and rattles when being shaken. Afterwards, coffee is put in special bags, where it ‘rests’ before halling (the process of separation of a seed from the rest of the dried fruit).
But what exactly determines the choice of processing method? Traditionally, it depends on climatic and geographical conditions. Natural processing is widespread in the regions that do not have access to water resources (primarily in Ethiopia, where this method originated, and in some regions of Brazil). The choice of a particular method also depends on the amount of expected rainfall: a large amount of precipitation is detrimental to natural processing as coffee berries can be damaged and sugar can be washed down from them.
It is impossible to say which processing method is better — it is just a matter of taste. Many coffee enthusiasts are convinced that, despite the obsolescence and relative simplicity of dry processing, only this method can infuse a truly extraordinary and delicate taste into a coffee drink.
Other coffee lovers hold opposite opinions, considering naturally processed coffee excessively full body and repulsively sharp. But one thing can be said for sure — dry processing definitely adds fruitiness and sweetness to coffee, regardless of its variety and region, and the general flavours present in the drinks brewed from such coffee are strawberries, tropical fruits and honey, but, on the other hand, they can also have some tart and alcoholic hints.
And next time we’ll talk about washed coffee processing 😉 Stay tuned!