Japan's 'kōji' unleashes umami in our kitchens

The fermented mould, which unlocks sweet-savoury flavours, has become a foundation for culinary experiments in India

- Insia Lacewalla

What happens when steamed grains are laid out under muslin, left to rest in warm, humid air? Within days, a delicate white bloom spreads across the surface, releasing a nutty, almost chestnut-like aroma. It might appear to be a science experiment, but, in fact, is a culinary revolution in slow motion—kōji, or Japanese fermented rice (or barley) mould that is quietly building flavour blocks in Indian gastronomy.

Kōji has long been revered in Japan for its ability to break down starches and proteins into sugars and amino acids, unlocking deep savoury flavour, what chefs and scientists alike call umami. Once confined to Japanese kitchens, the fungi Aspergillus oryzae is now being harnessed by a growing tribe of Indian chefs, brewers and fermenters in creative ways. From reimagined tandoori marinades to kōji-laced cocktails, its applications are expanding fast.

At INJA, the Indian-Japanese restaurant in Delhi, chef Adwait Anantwar uses kōji to make miso—a fermented soybean paste that uses kōji as a starter culture, rendering a unique flavour. He uses locally sourced cashews and peanuts to make miso tailored to local palates. It lends depth to curries, while a syrupy kōji glaze brightens up everything from chicken wings to a vegetarian banana bonito.

The rise of kōji aligns with a global fermentation revival. While fermentation is integral to Indian food culture—think dosa, kanji, or pickles—kōji offers something more: precision. Traditional Indian fermentation methods are often more intuitive and variable.