Koji-Fermented Coffee May Bring Sustainable Profits To Impoverished Bean Farmers

Koji is a culinary keyword these days. It is the beneficial mold used to make most fermented foods in Japan such as miso, soy sauce and sake. 

Now chefs all over the world are experimenting with koji in a variety of ways. Moving forward, on October 23, 2021, koji went on to a new stage: The World Barista Championship in Milan, Italy. 

Kaapo Paavolainen, the Finnish Barista Champion in 2020 and 2021, presented his original, koji-fermented coffee to the judges. 

While he did not make it to the top 6 at the competition, he was thrilled to have introduced the innovative method to the world – he was eyeing something bigger than a great cup of coffee. The new method can potentially bring more opportunities for coffee farms that are suffering financially. 

According to Enveritas, 44% of the world’s smallholder coffee farmers are living in poverty and 22% are in extreme poverty. Paavolainen’s new invention can help bean farmers to earn more sustainable profits because he discovered that koji’s unique property can transform ordinary beans into noticeably better-quality products. 

About a year and a half ago, Paavolainen was pondering how to make better coffee than what was available. “The existing processing methods of coffee is not fully maximizing the potential of beans,” he says. “Sugar in beans is responsible for coffee’s inherent sweetness but the lack of it results in unpleasant bitterness. But the current methods can extract only 70% of available sugar.”

Then he realized that koji has a unique property to tap into the remaining 30% of sugar in beans, after reading two books:  Koji Alchemy by Jeremy Umansky and Rich Shih, and The Noma Guide to Fermentation by Rene Redzepi and David Zilber. “Koji can be cultivated on pretty much any starch, which is amazing, because it can grow on the previously unused starches of coffee beans, such as skin, mucilage and pulp,” says Paavolainen.

To apply his novel idea into practice, he contacted coffee consultant Christopher Feran in Cleveland, Ohio and partnered with the El Vergel farm in Colombia for the special bean production. Koichi Higuchi of Higuchi Matsunosuke Shoten, a koji spore purveyor in Osaka and the aforementioned Koji Alchemy’s author Jeremy Umansky also advised the team on technical details.  

Feran, who also works as a coffee buyer and taster and was formerly a Licensed Q-Arabica Quality Grader for the Coffee Quality Institute, devised a series of koji-based processing protocols for Paavolainen.

Koji Can Transform Sub-Par Beans To Excellent Beans

The results were impressive. Umansky described the new coffee as “deep, earthy and leathery. It had a toasty rich aroma like soy sauce without salt and fermented notes. Depending on the roasting level of the beans, the flavor ranged widely from tropical fruits like pineapple and mango to chocolate and gingerbread. The mouthfeel was strikingly silky and luxurious like butter or juicy roasted meat. The full-bodied texture made these tastes last very long.”

Umami is the fifth taste after salty, sweet, sour and bitter and it naturally enhances or rounds out the other four tastes to make food delicious. Koji can produce powerful enzymes to break down protein to amino acids, which is the source of umami. So it makes sense that the koji-fermented coffee expresses the flavor profile that is typical in umami-rich foods as Umansky found.   

Higuchi, who himself already experimented production of koji-fermented coffee, says he was impressed with Paavolainen’s new method of using beans’ pulp. “Since I could not legally import the whole coffee cherries to Japan, I was only able to grow koji on already processed beans without the outer parts in my trials. I am surprised to see the data from El Vergel that koji grew rather fast on beans’ pulps and went through healthy fermentation without special equipment or facilities.”

The most remarkable thing about the new koji-based method is that the team intentionally used subpar beans for the experiments. “We compared cups of the original beans and the koji-fermented ones. The transformation of the beans was incredible,” says Umansky. 

Also, the new method does not require massive investment. “Koji may cost $35 for a small bag of starter spores. On the other hand, the standard yeast inoculation using common strains costs anywhere from $0.12 per pound to $0.25 per pound.  But koji is more cost-effective because it can scale to a producer’s need as much as its entire harvest,” says Feran. 

The new method is revolutionary but not for everyone though. “If you have perfect beans, you probably don’t need it,” says Umansky. And it may not be accepted by coffee farms, even if they know they could take advantage of it. “To try the new method, farms still have to pay for small items like a pH meter. Those few hundred dollars seem nothing for us in the developed countries, but it could be worth thousands of dollars for the farms that are already operating at extremely thin margins.” 

However, there are farms that are showing a strong interest in the new koji method. Paavolainen’s team has already received inquiries from producers in the Philippines, Thailand, Brazil, Vietnam, Colombia and China in replicating the process at their farms.

“We are currently working to scale the process with the partner farm El Vergel in Columbia to produce a 300kg lot of green coffee using this process for export with the help of Higuchi’s lab in Osaka,” says Feran. 

Paavolainen is fully committed to making his invention work to support coffee farms. “I believe koji-processed coffee has a glorious future ahead. I am hoping to bring a more refined version of koji-fermented coffee with a different varietal to the 2022 World Barista competition.  I have to keep on proving the effectiveness of the new method until people believe it.”