Experimental

Experimental processing is an innovative approach to coffee production that goes beyond traditional methods to preserve quality while enhancing or even introducing new flavours.

In recent years, the speciality coffee market has seen a surge in these techniques, driven by evolving consumer tastes and growing competition. Unlike conventional processes like washed or natural methods, experimental processing is often more intricate. It involves additional variables and demands a higher level of expertise and effort from farmers, making it as much an art as it is a science. This meticulous attention to detail often results in unique and captivating flavour profiles that excite coffee enthusiasts around the world.

Fermentation is a natural process that begins as soon as coffee cherries are picked. In recent years, producers have embraced this process as a way to unlock new and exciting flavours in coffee.

In aerobic fermentation, oxygen is present, which accelerates the fermentation of sugars in the coffee. By contrast, anaerobic fermentation takes place in an oxygen-free environment, slowing the fermentation process. This slower pace allows microorganisms to break down sugars more gradually, creating the potential for deeper and more complex flavours.

The way the cherries are treated also influences the process. In natural fermentation, the cherries are left whole, while in washed fermentation, the beans are stripped of their skin, flesh, and mucilage before fermentation begins. Both methods, whether aerobic or anaerobic, are pushing the boundaries of coffee flavour, reflecting the creativity and skill of today’s coffee producers.

Carbonic maceration is a coffee processing technique inspired by winemaking, where it’s traditionally used to develop grapes before they are crushed. This method is a form of anaerobic fermentation, taking place in an oxygen-free environment.

To achieve this, harvested coffee cherries are placed in airtight barrels, and CO₂ is pumped in to create a carbon dioxide-rich atmosphere. This environment enables the cherries to break down various levels of pectins, leading to distinctive flavour profiles. Coffees processed through carbonic maceration are often bright and winey, with pronounced red fruit notes. This innovative approach showcases the fascinating intersection of coffee and winemaking traditions.

Lactic fermentation is a coffee processing method where producers introduce lactic acid cultures during the fermentation process. Coffees processed with lactic fermentation often feature a creamier mouthfeel and distinct yoghurt-like flavours. This approach adds a smooth, tangy character that stands out, making it a popular choice for those seeking a different sensory experience in their cup.

Double fermentation is a coffee processing method where the coffee undergoes two distinct fermentation stages, a technique widely used in Kenya.

In this process, the cherries are first depulped and fermented in water for up to 24 hours. After this initial stage, the mucilage is removed, and the beans undergo a second fermentation for an additional 24 hours.

This meticulous method removes more mucilage than many other processes, typically resulting in coffees with brighter acidity and cleaner flavours. Double fermentation is celebrated for creating exceptionally crisp and refined cups that highlight the unique qualities of the coffee.

Co-fermentation is a coffee processing technique where natural ingredients—such as fruits, herbs, or spices—are introduced during the fermentation process. This method enhances the traditional fermentation process while creating unique flavour profiles.

Unlike infused coffees, co-fermentation allows the inherent qualities of the coffee's variety and terroir to shine, complemented by the subtle influence of the added ingredients. These additions can highlight specific aspects of the coffee’s natural flavour potential, resulting in a cup that is both distinctive and true to its origins. Co-fermentation is a creative approach that offers a fresh perspective on the possibilities of coffee flavour.

Yeast fermentation is a coffee processing method where specific strains of yeast are introduced in a controlled environment to enhance the fermentation process. While yeast naturally occurs during coffee fermentation, intentionally adding a yeast starter to green coffee allows producers to unlock unique flavour characteristics.

This approach can impart an extra layer of complexity to the coffee, sometimes resembling the crisp flavour profiles found in whiskey or white rum. Beyond enhancing taste, yeast fermentation can also elevate green bean cupping scores, making it an increasingly popular method for producers seeking to craft distinctive and high-quality coffees.

Thermal shock is an advanced coffee processing method that combines low-oxygen fermentation (a type of anaerobic fermentation) with precisely controlled hot and cold washes to create unique flavour profiles.

The process begins with a hot wash, which opens the pores in the parchment and silverskin, allowing flavour compounds to penetrate the coffee beans. This is followed by a cold wash to clean the parchment and rapidly cool the beans. After washing, the beans are dried using a specialised mechanical dryer that gently removes moisture with a dehydrator and low-temperature carbon dioxide or nitrogen. This careful drying process ensures the beans aren’t exposed to oxygen or excessive heat, preserving and enhancing their flavour compounds.

Thermal shock processing is known for boosting the coffee’s sweetness and elevating its overall flavour complexity, making it a sought-after technique for creating truly exceptional coffees.