Kanji (Fermented Rice Water)
The world's oldest probiotic drink — cooked rice left to ferment overnight produces a live-culture beverage consumed for gut health across South and Southeast Asia for millennia.
— Definition
Kanji is the fermented water produced when cooked rice is left to soak overnight at room temperature. Naturally occurring Lactobacillus bacteria on the rice ferment the starch, producing lactic acid and a range of B vitamins.
— In Detail
Kanji preparation: cook rice normally, leave the excess cooking water (or add fresh water to cooked rice) and allow to ferment at room temperature for 8–16 hours. The result is a mildly sour, slightly effervescent liquid consumed in the morning on an empty stomach. Nutritional changes during fermentation: B12 increases dramatically (rice contains no B12, but fermenting bacteria synthesise it), folate increases, available iron increases as phytic acid is reduced, and lactic acid bacteria colonise the gut. Rice kanji is distinct from the North Indian 'kanji' (black carrot pickle brine), though both are fermented. The Kerala and Tamil Nadu tradition of Pazham Kanji (overnight fermented rice) is one of the most documented traditional probiotic practices in India.
— Why It Matters
Kanji provides a zero-cost, zero-equipment probiotic that requires only leftover cooked rice. Studies from the International Rice Research Institute (IRRI) showed that fermented rice water increased available iron by 200% compared to freshly cooked rice. For a country with 59% of children under 5 anaemic and most of the population already eating rice daily, kanji is the most practical dietary intervention available — and it was already in use for 3,000 years before anyone measured it.
— Related Terms
— See in Field Guide
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