As the specialty coffee market has grown and diversified over the years, so have processing methods. More farmers have started using experimental processing methods to enhance coffee quality and flavour.
These processing methods can result in more complex sensory profiles, which also have more fruity flavours. In turn, they’ve become more popular among coffee professionals and consumers.
However, farmers must take care when manipulating fermentation to process coffee. By carefully controlling a range of variables during the process, producers can create some wonderful flavours in their coffee, and potentially increase its final cup score.
What is traditional fermentation?
Technically, fermentation in coffee production begins as soon as the cherry is picked. It is a chemical reaction where the combination of yeast, bacteria, and other microorganisms causes a substance to break down into other, simpler substances.
Usually, the substances that get broken down are sugars. Essentially, fermentation is a natural change that happens when sugar and water are combined, and coffee cherries contain both.
Notably, fermentation has the potential to improve a coffee’s flavour or ruin it entirely. Therefore, it must be carried out carefully and in a controlled manner – especially when it comes to experimental techniques.
Traditional processing methods include:
- Washed processing: Coffee cherries are de-pulped to remove the flesh and mucilage. Then, the beans are submerged in water to wash away any remaining mucilage. The green coffee is then left to dry on raised beds or patios.
- Natural processing: Ripe coffee cherries are dried on patios with the skin, flesh and mucilage intact. The cherries are turned regularly to ensure mould does not form. Once they’ve reached the optimal moisture level, the beans are removed.
- Honey processing: This method became prominent in Costa Rica when the government enforced strict regulations around water use. Essentially, it involves leaving a particular amount of flesh and mucilage on the coffee as it dries.
Importantly, there are different types of honey processing, including black, yellow, red, pink, and white. The colour indicates how much mucilage and flesh is left on the beans as they dry.
Understanding experimental processing techniques
Two of the most common experimental processing techniques in coffee today are aerobic and anaerobic fermentation. The fundamental difference between the two is the presence of oxygen.
Oxygen is included in the aerobic fermentation process, which means the sugars in the coffee beans ferment at a faster rate. As there is no oxygen present during the anaerobic fermentation process, the sugars break down slowly, which allows for more complex flavours to develop.
Carbonic maceration is an offshoot of the anaerobic fermentation process. It involves placing harvested coffee cherries in airtight barrels before pumping in CO2 to create a CO2-rich environment. The CO2 allows the cherries to break down different levels of pectins, often producing bright and winey coffees with strong notes of red fruits.
Unlike anaerobic fermentation, carbon maceration can take months to produce the right flavour of coffee. This is because the cherries are left whole when they are placed in the barrels, rather than being pulped.
Notably, each process must be carefully controlled to ensure the appropriate chemical changes take place at the right time.
Pros and cons of experimental fermentation
Fermentation is a complex process with many potential outcomes. For instance, uncontrolled fermentation can lead to coffee with chemical or mouldy flavours.
Beyond this, over-fermentation may lead to attributes such as acidity, body, and sweetness being significantly reduced. Therefore, producers must understand the processes behind fermentation so they can make informed decisions. This will help ensure both quality and consistency.
A combination of clever marketing and limited supply means coffee that has undergone experimental processing tends to command higher prices on the market. Experimental processing such as anaerobic fermentation can increase coffee prices up to US $54.10 per pound.
While this may seem like an attractive prospect for producers, it often lacks the long-term financial sustainability of traditional processed coffees. As a roaster, you understand that producers are the heart of the coffee supply chain. Therefore, encouraging them to find ways to keep coffee production profitable is in everyone’s best interest.
Where possible, forming direct relationships with producers and helping them invest in experimental fermentation can achieve this. Furthermore, roasters can communicate this relationship and the value that processing adds to customers using packaging.
Then, consumers will understand that a higher price tag is needed to keep coffee production going into the next century. Processing is a crucial stage in the journey of a coffee from seed to cup. It is responsible for imparting a number of characteristics, as well as for transforming it into a green bean ready for roasting.
While some processing methods are more sustainable than others, many producers are taking measures to make their practices conducive to the long-term future of the coffee industry.
At MTPak Coffee, we can help to highlight the unique qualities of sustainable coffee processing with our range of compostable, biodegradable and recyclable packaging, that can be fully customised to make your coffees stand out.
Our sustainable coffee bags are made using kraft paper, rice paper, or multilayer LDPE packaging with an environmentally friendly PLA lining, while our coffee boxes are made with recycled cardboard. Our eco-friendly customisation techniques include spot UV with a glossy, satin, or matte finish, embossing and debossing, as well as hot foil stamping in a variety of colours.