Is fermented coffee the next big thing?

Almost every coffee drinker has heard of ‘kopi luwak’ coffee – the expensive coffee that’s made from the partially digested beans defecated by the Civet cat in Asia. It doesn’t sound particularly appetising and the commercial methods are less than ethical, but apparently, the coffee is crazy smooth. There might be a new, cleaner alternative on the horizon though, with scientists and chefs starting to experiment with koji-fermented coffee…

What is Koji exactly? It’s rice. Except, it’s not just rice. Fermentation is the new thing, and koji is a rice that’s been treated with koji mould (aka Aspergillus oryzae). Koji has a rich history in Japanese cuisine, and is essentially a type of fungus used in fermentation. By doing this fermentation process with the koji mould, the rice gets added flavour without any added salt or MSG. Koji has been traditionally used in miso, rice vinegars, soy sauces, saki and more. 

This mould’s fermenting powers are even celebrated annually in Japan on National Fungus Day! It’s traditionally used a method to add more flavour to foods. It will be interesting to see how koji might be used to expand the flavour profile of coffee.

Koji-fermented coffee

In an interview with Forbes, the creator of koji-fermented coffee, Koichi Higuchi (who studied bioscience at the University of Minnesota), revealed that the idea for koji-fermented coffee came out of a conversation with his friend, a coffee aficionado. Much like the Civet cat’s kopi luwak digestion process, koji contains enzymes that break down complex proteins, starches and fats, achieving a similar effect to that of kopi luwak, except in a lab rather than the cat’s digestive system. 

Koji spores are sprinkled over green coffee beans and fermented for a few days. Higuchi roasted the beans into a light and dark roast, and reported to Forbes: “Compared to regular beans, the dark roast gave milder taste, whereas the light roast had cleaner acidity. Also, I did not get the subtle burning sensation that I suffer from by drinking regular coffee.”

Some have suggested that the koji fermentation process might even add value to beans that are considered lower quality. Koji-fermented coffee is not yet commercially available, but we wait with baited breath to see how this amazing mould might bring bolder flavours to our daily cup of java.