Koji Making at Umekoji Fermentation Factory Kyoto – Snacks and Seasonal Sake Pairing Included

Connecting With Koji Culture

Umekoji Fermentation Factory is part of the newly built Umekoji Potel Kyoto hotel that opened in 2020 near Umekoji Park. Located in a nostalgic side alley dotted with lanterns, the facility aims to pass on the knowledge and tradition of fermentation and koji from the masters to the next generation. In the world of sake brewing, there’s a famous saying that goes, “First the koji, then the moto (yeast starter), followed by the tsukuri (fermentation).” And of that, the koji is the most important part. At Umekoji Fermentation Factory, you can experience this koji-making process firsthand.

Learn all about sake and fermentation in a fun, relaxing atmosphere

The koji muro, or koji room, is traditionally a sacred place where only a limited number of chief brewers can enter. The belief is that the god of sake dwells here, and it is strictly managed to prevent contamination from other bacteria not used in the fermentation process. The modern koji room at Umekoji Fermentation Factory was created to be more accessible so that everyday people can see and participate in the process. Here, you’ll get to do what previously only masters could do — make koji in the koji room.

The koji muro is considered a sacred place, home to the god of sake

Koji: The Origin of Japan's Fermentation Culture

First, an introduction to the manufacturing process and the history of fermentation by a koji master. You’ll learn how koji is the foundation of the essentials used in Japan’s food culture, such as soy sauce, miso, and sake and involves a variety of exacting processes that require considerable time and effort. 

Look close enough and it’s as if flowers are blooming on the rice

There are five major types of koji: yellow koji, white koji, black koji, red koji, and katsuobushi mold. In this experience, you’ll make either yellow koji or black koji depending on the day.

Black yeast rice, rich in citric acid, is highly effective for beauty and recovery from fatigue

Yellow koji, created for sake brewing, is a familiar koji used in miso, soy sauce, and other fermented foods. It’s characterized by a mild sweetness with few peculiarities. Black koji, on the other hand, is a type of koji used to make Awamori and other alcoholic beverages. It’s characterized by a fruity sourness due to its high citric acid content, and is highly effective for beauty and relieving fatigue.

Experiencing Tane-kiri, the Most Exciting Part of Koji Making

Next, the actual koji making. Begin by inspecting the steamed rice in the seiro, or bamboo steamer. This is an important step, as the degree of steaming determines how the koji will turn out. The correct way to steam it is until the rice is slightly soft but firm, and you can test it by gently pinching a grain of rice with your thumb and forefinger. To ensure that the quality of the rice is consistent throughout the bamboo steamer, check the rice by going over them carefully by hand.

Carefully check to ensure that the rice in every part of the bamboo steamer has the same consistency

Once the rice has been steamed correctly, it's finally time to enter the koji room. Here the steamed rice is mixed with a mold called tane koji, or koji starter. This is the most important step in koji making, called tane-kiri. In order to create an environment where koji mold can flourish, the room temperature is kept at about 30 degrees Celsius and the humidity at 60%.

Because koji mold is sensitive to heat, the steamed rice is spread out and kept at around 40 degrees Celsius. As the fermentation progresses, a sweet chestnut-like aroma permeates the air, and you’ll start to see the white mycelium taking over the surface of the rice grains. The growth of koji mold changes subtly depending on the season and weather.

Aspergillus oryzae, or koji mold, is a living organism that is sensitive to heat and humidity

While your job here is now done, this is only half the process. The staff at the shop will now watch over the growth of the koji on your behalf while carefully controlling the temperature and humidity levels for the next three days. The arduous process of taking care of koji as it matures is often likened to raising a baby. You'll receive a pack of dried koji to take home as a souvenir that is easy to store.

Over 3 days, the staff carefully watches over your hand-made koji

The Marriage of Koji and Sake Unique to Umekoji Fermentation Factory

After that hard but exciting work, you can now unwind with specially selected fermented snacks and pair it with 2 types of sake, plum wine and fruit wine selected according to the season. Non-alcoholic drinks are also available upon request. With your newfound knowledge and experience making koji, the treats will undoubtedly taste that much more delicious.

Enjoy two types of fermented snacks paired with carefully curated Japanese sake

Fermented snacks that go well with sake include seasonal steamed vegetables with koji sauce and homemade koji focaccia with, of course, plenty of koji. It’s the perfect opportunity to taste a combination of fermented foods together in unique pairings carefully curated by the koji experts.

Seasonal vegetables with salted onion koji sauce and black brown rice soy sauce with citrus fruits

At the end of the activity, you can purchase your favorite sake at the shop together with the seasonal vegetable pairings to replicate the gourmet experience again at home. Umekoji Fermentation Factory offers a wide selection of domestically produced alcoholic beverages, from sake to plum wine and wine.

Appreciating Fermented Food Culture in Everyday Life

You can enjoy black koji amazake as a complimentary drink. The black koji used to make this sake is characterized by its sweet and tangy notes which you’re sure to enjoy.

The shop offers over 160 varieties of domestic sake to choose from

Since it takes three days to make koji, you'll also get to choose a pack of dried koji to take home, together with recipes and tips on how to fully enjoy it. "Should I make amazake, or should I use it for shio koji?" These are the exciting decisions you’ll get to make at home!

Learn how to use koji at home with the included recipes

At Umekoji Fermentation Factory, you can experience Japanese fermentation culture with all five senses. We invite you to enrich your journey in Japan with this unique opportunity to experience the country’s famed fermented food culture firsthand through koji.