The different coffee processing methods

Coffee goes through several stages before reaching your cup, and processing is one of the most important. Besides being essential for preserving the quality of the bean, processing helps enhance certain flavors and even create new ones.

During our initial travels, we saw all sorts of processes, ranging from traditional to highly experimental. Here are a few examples!

Understanding the anatomy of the coffee cherry

The coffee tree produces coffee cherries, and the beans we roast and brew are the seeds inside! The skin of a coffee cherry is green until the fruit ripens to a bright red, yellow, orange, or even pink, depending on the variety. Beneath the cherry's skin is a thin layer called the mesocarp, more commonly known as the pulp. Mucilage is the inner layer of the pulp, full of sugars; it's essential for fermentation.

Coffee beans, meanwhile, usually come in pairs in the cherry (except for 5% of coffees, which are known as Peaberry ), and each is covered with a thin epidermis called the silverskin and a papery layer called parchment.

The parchment is usually removed during hulling, which is the first step in the dry milling process. Machines or millstones are used to remove the remaining fruit and dried parchment from the beans. But sometimes, green beans are sold with this layer intact as parchment coffee.

Washed process

Popular in parts of Africa (including Rwanda and Kenya) and Central America, as well as in Colombia, this processing method involves removing all the flesh and mucilage from the grains before they are dried.

After harvesting, the cherries are pulped to remove the skin and pulp, then usually soaked in water to wash away any remaining mucilage. Once the mucilage is removed, the green coffee is then left to dry on raised beds or terraces.

Washed coffees are generally brighter and have a cleaner taste than those processed using other methods. This is because removing the cherry allows the coffee's inherent and natural characteristics to shine through.

Natural Process

Natural transformation is common in regions and countries where access to water is limited, such as Kenya, Ethiopia, and Brazil.

Once the ripe cherries are picked and sorted, they are dried completely intact on patios (including the skin, flesh, and mucilage) and are regularly turned to prevent mold growth. Once the cherries have reached the optimal moisture level (between 10% and 12%), the seeds are removed.

Most naturally processed coffees have fruitier flavors and are generally sweeter and fuller-bodied. They can sometimes have wine-like characteristics and a heavier mouthfeel.

Honey Process

The Honey Process is popular in some Central American countries, especially in Costa Rica, where it was first developed and where we had the chance to see it in detail.

The Honey process involves leaving a specific amount of pulp and mucilage on the coffee as it dries. Like many newer processing methods, the Honey process is a hybrid of traditional and innovative techniques.

There are different types of Honey coffee, including Black Honey, White Honey, Yellow Honey, and Red Honey. These colors indicate the amount of pulp and mucilage remaining on the coffee when it dries.

For example, Black Honey is similar to naturally processed coffee because most of the skin, fruit, and mucilage remain on the beans during drying. In comparison, White Honey is more like washed coffee because most of the pulp and mucilage is removed, resulting in a milder cup profile. Due to the diversity of honey processing techniques, these coffees can have a variety of flavor profiles, but generally, they tend to have sweeter profiles.

Anaerobic fermentation

Experimental processing methods are not new to specialty coffee. In many producing countries, tradition and innovation coexist in coffee processing to improve the quality and sustainability of the final product.

However, in recent years there has been a notable increase in the number of increasingly innovative treatment methods. These are generally more complex than traditional methods, as they involve more variables and require farmers to exercise closer control over the process.

While visiting farms and mills, we witnessed firsthand the rise of anaerobic fermentation , which has been gaining popularity for several years. With this method, coffee beans are fermented in airtight containers. This process is carried out using whole cherries, which can be fermented for up to 96 hours in some cases.

Since there is no exposure to oxygen with anaerobic fermentation, microorganisms break down sugars at a much slower rate, allowing for the development of more complex flavors!