Learn to Cook Traditional Japanese Food with Koji at a Centuries-Old Shop in Osaka

Experience Japanese Food Culture at a Long-Running Koji Shop

Koji is made by cultivating koji bacteria on grains like rice, wheat, and soybeans. It's a key ingredient in many staples of Japanese cuisine, including soy sauce, miso, sake, shochu, mirin, vinegar, and pickles. Koji plays an important, often unseen, role in traditional Japanese food culture.

Amazake, miso, and shio koji are all made using koji bacteria

Koujiya Amekaze is a historic shop in Sakai, Osaka, with over 330 years of history. Founded in 1689 as a soy sauce brewery, it earned the nickname "Amekazeya-san" (literally, "rain and wind shop") for staying open even in inclement weather, and the name stuck.

Today, the shop specializes in koji, along with miso, soy sauce, and koji-based drinks like amazake and doburoku sake. Upholding its long-standing traditions, Koujiya Amekaze still uses ancient methods to make koji and shares its appeal through cooking classes and a cafe.

A charming shopfront reflecting its rich history

Lecture on the Basics of Koji and How to Use It

This experience takes place at Biotopos, a cafe next to the main shop, and begins with a lecture on koji.

Biotopos, a koji-themed cafe

In the lecture, you'll learn about koji basics, its history and culture, how it's made, and the role of koji bacteria's enzymes. These enzymes break down starches into sugars and proteins into amino acids, boosting both nutritional value and flavors like sweetness and umami.

The instructor will explain how to use various fermented seasonings

An expert instructor will teach you how to use koji products like shio koji (salted koji) and shoyu koji (soy sauce koji), as well as fermented seasonings such as miso and amazake.

Miso has been a vital part of the Japanese diet for centuries

For example, miso can be used in boiling, pickling, baking, or mixing, and adds richness to dishes like curry or pasta. Amazake can be enjoyed on its own or diluted with milk or soy milk, and can also be used as a sweetener.

The lecture will help you understand how to use koji and fermented seasonings, making these ingredients feel more familiar and less intimidating.

Enjoy Learning While Cooking

After the lecture, you'll prepare dishes using koji with the instructor's guidance. The menu includes three types of onigiri rice balls with different seasonings, miso soup, a fish dish, stewed vegetables, salad, and pickles. Vegans can substitute the fish with tofu hamburger or deep-fried tofu dengaku (miso-glazed tofu), and use kelp broth for the miso soup.

When making miso soup, gradually dissolve the miso with a ladle to ensure it’s fully mixed

Cooking with koji is easier than it seems. Simply spread white miso on your handmade onigiri and brown them with a burner. For the other two types, use Koujiya Amekaze's original shoyu koji sauce and homemade miso.

Learn to make onigiri, a staple of Japanese comfort food

For the fish dish, coat the filet in a miso sauce made from equal parts white miso and amazake, then let them marinate. When grilling, use a frying pan and cook over low heat to prevent burning. Marinating in miso keeps the fish moist, enhances its flavor, and makes it more delicious.

Miso-marinated fish uses seasonal ingredients (image for illustration only)

Enjoy a Koji Meal Featuring One Soup and Three Side Dishes

Once all the dishes are ready, enjoy them while they're fresh—nothing beats the taste of a meal you’ve made yourself. Ichiju-sansai, which includes rice, soup, and three side dishes, is a staple of Japanese cuisine and offers great nutritional balance. The sansai (three side dishes) typically include a protein-rich main dish like meat or fish, along with two vegetable or seaweed sides, providing a well-rounded meal.

An ichiju-sansai (one soup, three dishes) menu with seasonal ingredients (image for illustration only)

Prepared with the best seasonal ingredients and fermented seasonings that enhance their sweetness and flavor, these dishes are deeply satisfying with every bite. Enjoy the aroma of grilled onigiri, the rich taste of miso soup, and other nutritious side dishes.

Recreate the Traditional Japanese Dishes You Learned at Home

After the experience, you can take home pesticide-free dried koji (400g per participant) as a souvenir. It comes with recipes for making shio koji and shoyu koji, so you can create your own fermented seasonings and enjoy koji dishes even at home.

Dried koji can be stored at room temperature for up to six months. Keep it in a cool, dry place, or refrigerate for longer freshness

Koji dishes are known for their healthy and gentle flavors. At Koujiya Amekaze, you'll learn how to appreciate koji and its role in Japanese cuisine. By understanding koji better, you can bring Japan's traditional fermentation culture into your everyday cooking and give your diet a boost.