With its root in Kyushu’s food traditions, yuzu koshō is a salty, citrusy, spicy condiment.

Although it was originally made in local homes, within the past few decades, companies have begun bottling and selling yuzu koshō commercially, leading to an increase in its popularity. Due to the sustained national boom these past 10 years, this local Kyushu condiment is now made all over Japan, to varying degrees of success. And, thanks to a few key producers, such as Kushino Nouen, who make yuzu koshō responsibly and ethically, using local materials without additives or preservatives, Japan’s yuzu koshō boom shows no signs of letting up.

More recently, yuzu koshō is becoming well-known beyond Japan, perhaps because of the worldwide craze for ramen. And while yuzu koshō is extremely well-suited to salt-broth ramen, I like it thinned with olive oil and used as a drizzle for kelp-wicked sashimi or mixed sparingly into vinegar for a spicy mignonette alternative on oysters; but stirred into mayonnaise and slathered on a thick sandwich or as a dip for oven-baked French fries might be its best use yet.

Although commercial yuzu koshō might be a relatively new phenomenon, its ingredients — yuzu citrus, chili peppers and salt — have a long history in Japanese cuisine.

Yuzu, which originated in the Chinese Yangtze River basin, found its way into Japan through the Korean Peninsula somewhere between the late 500s to mid-700s, during Japan’s Asuka and Nara periods, and, along with sanshō (Japanese pepper), is one of the oldest culinary flavors in Japan.

Passing the taste of time: Yuzu is one of the oldest culinary flavors in Japan.
Passing the taste of time: Yuzu is one of the oldest culinary flavors in Japan. | COURTESY OF KUSHINO NOUEN

Portuguese missionaries first introduced tōgarashi (chili peppers) to Japan in the mid-16th century. Many people do not associate chili peppers with Japanese cuisine, but they are used to infuse a hint of spice into many dishes. The kanji for tōgarashi signify “foreign mustard,” and chilis are sometimes called yōgoshō (Western pepper). In Kyushu, chiles, simply known as koshō, the Japanese word for black pepper, are widely grown and used commonly in daily cuisine, hence the condiment’s name — yuzu koshō, or colloquially, yuzu goshō.

In 2016, I began a consulting project to introduce top artisanal Japanese products to Australia. One of the products I wanted to introduce was yuzu koshō, so I set about looking for the best one produced in Japan. Myoho Asari, the legendary Oita Prefecture-based kōji (the Aspergillus oryzae spore, which is used as a fermenting agent) maker who discovered, developed and shared shio kōji (a preserving agent made with kōji and salt) with the world, connected me to four producers, and Kushino Nouen was the clear frontrunner. Thus started my relationship with Kushino Nouen and its office manager, Miwa Kawano.

Bring on the heat: Chili peppers are widely grown in Kyushu.
Bring on the heat: Chili peppers are widely grown in Kyushu. | COURTESY OF KUSHINO NOUEN

Kushino Nouen is located in the tiny 4,500-person town of Innai (now incorporated with the slightly larger Ajimu into the city of Usa), Oita Prefecture. The Limited Express Sonic 11, a gorgeous retro-looking train with glossy wooden flooring and moquette seats takes me from Kokura to Yanagigaura, where I am picked up by the surprisingly young, but extremely capable, Kawano. She turns me over to her father, Masaharu Kushino, who walks me through each step of the production process, all of which takes place within a short walk of his home and office.

Kushino Nouen’s yuzu koshō is made with green or red chilis, yellow yuzu peels from ripe fruit and Japanese sea salt. The chilis are either grown on Kushino’s farm or by friends, and the fruit is all harvested from trees — which were planted around 1974 — at Kushino Nouen. This means that both yuzu and chilis can be harvested at optimal conditions, and Kushino can ensure non-pesticide-treated materials are used. Each year, the salt is specifically chosen to be best-suited for interacting with the flavor of that season’s yuzu and chilis. Other companies use yuzu and chilis that are overripe and oversized in order to increase production and profit, but ultimately this negatively affects the taste, resulting in an inferior yuzu koshō.

The chilis are sorted, sliced into strips, packed in salt and left to macerate for a couple months. Any accumulated liquids are drained off, and the chilis are put through a mixer to be processed into a rough paste, packed back into crocks and left to ferment for one year.

Peak produce: After it
Peak produce: After it’s harvested, yuzu citrus is peeled by hand before it is minced, salted, packed in crocks and left to ferment. | COURTESY OF KUSHINO NOUEN

The yuzu is harvested between mid-September and mid-October, and the fruit is also peeled, minced, salted, packed in crocks and left for several months to ferment. The last, crucial step before bottling is to mix the salt-fermented yuzu peel and chili together using a mixing apparatus fitted with a massive stone bowl to avoid any introduction of heat. The final ratios of Kushino Nouen’s yuzu koshō are 3-3-2 yuzu to chili to salt.

While writing “Preserving the Japanese Way” in 2014, I dubbed yuzu koshō “the new Sriracha.” It still has not gotten there, perhaps because the ingredients are more precious and the condiment itself is appreciably more expensive. While there certainly are other chili products in Japan, such as kanzuri (a spicy paste from Niigata Prefecture made with chili pepper, yuzu, salt and kōji), for me they lack nuance and universality: Truly, yuzu koshō might be the only spicy condiment you need.

For more information on Kushino Nouen, visit kushino-nouen.com.

In line with COVID-19 guidelines, the government is strongly requesting that residents and visitors exercise caution if they choose to visit bars, restaurants, music venues and other public spaces.

In a time of both misinformation and too much information, quality journalism is more crucial than ever.
By subscribing, you can help us get the story right.