Who are WE?

We are Rotterdam based specialized in traditional koji making by using wooden steamer and tray. Mainly, we are producing Koji, Miso, Koji seasoning, and Amazake, but also carry out the workshop of Koji making, Miso, soy sauce, and others.

What is KOJI?

Koji is a sort of mold grain used in Miso, soy sauce, Sake, and Amazake. If you take a look on a label of Miso package you can find in the supermarket, you will see Aspergillus Oryzae which is Koji mold. Without Koji mold and Koji, Japanese fermented ingredients or sake cannot be produced. Therefore, Koji is the fundamental key element for Japanese food. Koji is the powerhouse of enzymes which is produced while Koji mold is growing on grains. When we make Koji, we not just make Koji. We always think which enzymes we will make for each purpose. Koji is a giver which provides human being with nutrition and enzymes without asking us of any cost. We guarantee once Koji get inside of you, it stays inside of you.


We have been deeply concerning about animal cruelty in recent years, global warming, environmental pollution, and food damage to human health. We realized that our daily choice would hurt planet, animals, and people with a lack of our knowledge. It could take the children’s future away. Since then, we chose the ethical life style, quit consuming animal products. We believe that we can do for planet and the children’s future even it is the just small thing.

Hiroki, the founder of CHORO KOJI FERMENTATION, had worked in infrastructure company in Japan. While he was stationed in the middle east in his career, he experienced extremely hot summer and realized how the global warming could be critical. Throughout the digging in the statistical data of global warming, he was surprised that animal agricultures account for approx. 15% of greenhouse gas emission. Consuming animal product directly leads to killing the planet which is our spaceship. While he studied food and nutrition due to the change of diet, he encountered microbes and Koji. He was purely enchanted with Koji and learn Koji philosophy and technique from Nakaji, the former Sake Brewer and currently running Koji Academy in Japan.


We harmonizes the fermentation technology that has been passed down from ancient Japan to the present day. Our products are organic, pesticide-free, and additive-free. Feel the power of homemade raw koji that exerts high enzyme power.



We make a big difference by small step and Koji.


We use local organic material in EU, minimize the plastic waste, utilize green energy, and share a knowledge to others.


  • Locally made and eco friendly Koji, Miso, and Amazake.
  • Sharing fermentation knowledge throughout workshop and interactive communication.