Handpicking
Most specialty coffees will have been hand-picked by either a team of pickers (on an estate) or by the farmers themselves (smallholder/cooperatives). For the coffee to be complex in the cup, it is essential that the cherries have reached maturity when they are picked – pickers using this method should therefore only be selecting the ripe cherries, leaving any immature fruit on the tree to be harvested during another pass of the farm. Depending on the farm size, there can be up to ten passes to ensure the cherries are picked at the right time. Most pickers are paid by the weight of cherry that they deliver so most farmers have a hard time incentivizing their pickers to selectively harvest the crop, many will pay a premium for good quality ripe cherry.

This is arguably the oldest and most original form of coffee processing and was traditionally used to process cherries on a commercial scale due to the low costs involved (i.e in Brazil) or in areas with limited access to water resources (i.e Ethiopia).

After harvesting, the cherries are laid out to dry in the sun – on a commercial scale, they are usually laid on large concrete or brick patios though they are sometimes left directly on the earth to reduce the moisture content. It is for this reason that natural processed coffees will often throw up more defects in the cup – they can sometimes have an intense earthy flavour due to the soil they have been dried on! Traditionally, it has been washed coffees that have attracted higher prices due to their cleanliness and uniformity, though more and more specialty buyers have invested in the natural process due to the potential for flavour profile experimentation.

If done properly whereby ripe cherries are laid on raised beds in thin layers and regularly turned to reduce the risk of mould growth, natural processed coffees can have the most incredible cup profile with flavours such as ripe strawberry, mango and blueberry being commonplace. The cherry is dried with all of the layers intact which means there is a certain amount of natural fermentation occurring in the bean in its own environment – many enzymatic bi-products are absorbed from the mucilage into the heart of the coffee bean which can result in an incredibly distinct flavour profile. Once dry, the cherries will resemble raisins and when they have reached this state, the coffee is hulled to remove the outer layers before being sorted in a ‘dry mill’ for shipment.

The washed process is widely used across Latin America and parts of East Africa and requires both the cherry and mucilage surrounding the parchment to be removed with the use of friction, fermentation and water.

Once the ripe cherries have been picked, they are delivered to a wet mill where they are loaded into a depulping machine which forces the beans out of the cherry. At this stage, the beans are contained within the pulp of the cherry, also known as the mucilage. This sticky mucilage is composed of natural sugars and alcohols and contributes massively to the sweetness, acidity and overall flavour profile of the coffee.

Once the beans have been pulped, they are put into fermentation tanks for around 12-24 hours dependent on temperature, though farmers are now experimenting with fermentation time to develop different flavour profiles. For example, a longer fermentation means the beans have more time to absorb some of the sugars and can result in a slightly sweeter, ‘funkier’ flavour, though this can be a hard balance to strike as leave it too long and the beans become over-fermented with unpleasant vinegar-like characteristics.

Fermentation results in the mucilage being broken down leaving the beans in their parchment which are then ready to be washed. This can either happen in tanks of clean water or, in East Africa, it is often done in channels. Once the beans have been washed they will feel gritty in your hands which means they are now ready to be dried.

At this stage, the parchment beans are taken to drying tables (raised African beds) or to patios to sit for a period of around 10-22 days where they are gently turned. It is widely accepted that a slower drying time contributes to greater balance and complexity in the cup. Some washed coffees, particularly in Central America, are dried in large ‘guardiolas’ which are mechanical dryers often used if a farm or dry mill has a lack of space. In this instance, the coffee is dried in around 3 days and we have found from experience that this can sometimes reduce the shelf life of the green coffee, allowing aged characteristics to creep in at an earlier stage.

The washed process is arguably our favourite at North Star due to the incredibly bright and clean coffees that it can produce – washed Ethiopian and Kenyan coffees are fantastic examples of the clarity of flavour that can be coaxed out if the coffee is processed correctly.