Fermenting Coffee with Fruit – Trends in Speciality Coffee Sector

Speciality coffee buyers tastes are evolving with search for coffee with exotic flavour profiles and high cupping scores. This has urged coffee producers to usher in innovation in all aspects of production and processing. One such innovation is the idea of adding fruits during fermentation of coffee. Let us examine the process is in detail.

What is Fermentation?

Fermentation occurs naturally soon after the coffee cherry is picked. This might occur even earlier during high humid conditions. It is a process where yeast, bacteria and other microorganisms breaks down the sugar content in the mucilage inside the coffee cherry.

This gives rise to acids and alcohols, which in turn can influence the coffee flavour. Fermentation is a sensitive process that are greatly influenced by the changes in the environment such as temperature, humidity and the presence of oxygen. Poor fermentation can produce mouldy or undesirable flavours in coffee, hence controlling the process is extremely critical.

In the light of growing demand for high quality coffee with unique flavour profiles many speciality coffee producers are trying out new and innovative fermentation techniques including carbonic maceration.

Coffee fermentation grew in to an area of focus for specialty coffee producers only in the past decade. Prior to that the focus was only on producing high yield as the demand was less. Coffee would be set out to dry as quickly as possible, either out in the sun or in the dryer and there were no attempts to explore fermentation. The humidity levels were reduced faster and curtailed the possibility of exploring the microbial richness that exists in the coffee’s mucilage.

Adding Fruit to Coffee

Latest innovation in the speciality coffee sector is to add fruit while fermenting coffee. Cut fruits like cherries, lemon, and bananas are fermented in a sealed, air tight tank for anaerobic fermentation along with a pre-determined percentile of whole fruits or extracts for a fixed period of time. The tank’s temperature is closely monitored throughout this period.

At times fruits are partially crushed in a bag and added to a tank with naturally processed coffee at a 1:5 fruit-coffee ratio for 72 hours.

Later on, it the processing is continued as usual. But the issue with this method is that we cannot be sure whether the outcome is from the interference or from the coffee bean itself.

Realizing the potential to deliver a more complex unique taste to coffee, CEO of Kerchanshe Trading PLC, Israel Degfa has adopted the process in their Adola Farm.

Does Fruit Fermentation Really Work?

Regulating fermentation is still a relatively new concept in coffee processing. It is yet to be learned about the influence it has on the coffee’s final cup profile. More Scientific research is needed to done in general and fruit fermentation in particular. This should also include the effect wort (the liquid produced during fermentation) has on the overall flavour profile of coffee.

Challenges Ahead

Any new territory is not without challenges.

The chief challenge for producers who wish to experiment with fermentation methods is that the market for such coffee is still evolving. Also, it should be kept it in mind that such coffee is not for everyday consumption and it should be viewed more like fine wine. Hence producers should consider if they have an accessible market for such experimental coffees.

Production costs is another major concern that the producers should be aware of. Also, fruit fermentation requires producers to carefully regulate various factors which can be labour intensive. If not, this could produce expensive coffee that doesn’t taste good.

In short, an advice for producers who are looking to experiment with fruit fermentation is to proceed with caution and with as much professional support as possible.