Time as an Ingredient: How Koji Introduced the Fermentation Clock to the Kitchen

The Michelin Guide’s inspectors have identified seven food trends for 2026. One of them is “Time Is an Ingredient.” Vegetables, fish, and meat are marinated or left to ferment slowly, in some cases with the introduction of koji. That is how the report frames it.

Viewing time as an ingredient might sound abstract at first. Yet when observing the path koji has taken into professional kitchens worldwide, the phrase turns out to be remarkably precise.

Purchasing Fermentation vs. Initiating It

Southeast Asia possesses a deeply rooted tradition of fermented foods: Thailand’s nam pla (fish sauce) and kapi (fermented shrimp paste), Malaysia’s belacan, Vietnam’s nuoc mam, and Indonesia’s terasi. Each is crafted over extended periods, forming the culinary backbone of its respective culture.

Yet they share a common trait: by the time these ingredients reach a restaurant kitchen, the essential work of fermentation is already complete. Producers craft them according to local methods and climate; chefs purchase and integrate them into dishes. The time that went into their creation exists entirely outside the kitchen.

Koji operates differently. To what ingredient should the koji be applied? At what temperature and humidity? For how long? These choices move directly into the kitchen. This shift is precisely what the phrase “time as an ingredient” captures.

Enzymes Care Little for Origin

Koji mold produces two principal types of enzymes: proteases, which break down proteins into amino acids, and amylases, which convert starches into sugars. The resulting umami and natural sweetness emerge directly from these enzymatic processes.

Strictly speaking, this transformation is driven by enzymes synthesized by koji mold, making it distinct from fermentation driven by living yeast or lactic acid bacteria. In professional kitchens, however, the broader transformation is often encompassed under the term “fermentation.”

What matters is that these enzymes are indifferent to origin. Where protein exists, proteases act; where starch exists, amylases act. To an enzyme, nationality does not exist.

This does not imply that koji works identically across all ingredients. For instance, in low-starch fruits, amylase has little substrate to engage with. Its effects are most pronounced in ingredients where the necessary substrates are clearly present: meat, fish, legumes, and starch-rich root vegetables.

Even so, the implication is profound. Koji is not merely a tool for recreating Japanese flavor profiles. It is a technique for unlocking latent potential already residing within local ingredients.

A Movement Already Underway

In August 2026, the South China Morning Post reported that fermentation is reshaping the internal architecture of fine-dining kitchens in Hong Kong. From kombucha brewing to miso production and lactic fermentation, kitchens are increasingly managing these transformations in-house.

Bangkok is equally engaged in this evolution. The Michelin report cites Baan Tepa in Bangkok as an example of a venue practicing internal fermentation. The same report separately mentions koji as well. The shift toward designing fermentation time within the kitchen itself is actively unfolding in this city.

From our perspective as practitioners who work with koji, the nature of inquiries from kitchens has also evolved. A kitchen seeking a finished condiment requires a fundamentally different dialogue from one seeking active koji. At KOUJI ALCHEMIST by salon du japonisant, our focus remains on guiding this exact distinction, offering chefs the precise understanding required to master the process.

The Chef Who Holds the Clock

To frame koji’s growing international presence simply as “Japanese fermentation culture going global” tells only part of the story. Kitchens are not merely adopting a finished product like miso or soy sauce. They are acquiring the agency to define how time shapes their culinary creations.

Once chefs hold the fermentation clock in their own hands, they can apply time, on their own terms, to the native ingredients around them. What emerges from that kitchen cannot be neatly categorized as Japanese or Thai. It becomes an expression unique to that space alone.

This article is intended solely to explore the culinary and cultural context of koji fermentation, for informational purposes only, and does not aim to promote or encourage the consumption of alcohol. / บทความนี้จัดทำขึ้นเพื่อนำเสนอข้อมูลเกี่ยวกับบริบททางการทำอาหารและวัฒนธรรมของการหมักด้วยโคจิ เพื่อเป็นข้อมูลความรู้เท่านั้น มิได้มีเจตนาเพื่อส่งเสริมหรือโฆษณาเครื่องดื่มแอลกอฮอล์ สำหรับผู้มีอายุ 20 ปีขึ้นไป โปรดดื่มอย่างรับผิดชอบ