Kanji is a sour, purple, mustard-sharp drink from North India, made by fermenting black carrots in salted water with ground mustard seed (rai) for a few days. The carrot sticks are eaten too. Black carrots – deep purple right through, rich in anthocyanin pigments – are grown mainly in northern India, and kanji is the best-known way of using them (Sharma et al., 2021).
What Happens in the Jar
Kanji is a lactic acid ferment, like fermented carrots in brine, but with far more water, so the result is a drink. Researchers in Ludhiana, Punjab, followed a naturally fermented batch: over 5 days at room temperature its pH fell from 6 to 3.47, lactic acid rose to 0.99%, and lactic acid bacteria multiplied from about 9,000 to more than 200 million per millilitre (3.96 to 8.33 log CFU/mL). The most vigorous of the bacteria they isolated was Pediococcus acidilactici (Sharma et al., 2021). Another group isolated Levilactobacillus brevis from kanji (Afreen et al., 2023).
The mustard brings heat and aroma; the black carrots bring the color, which leaches into the water as the carrots soften.
Is Kanji Probiotic?
Fresh, unpasteurized kanji is full of live lactic acid bacteria, and researchers describe it as a potential plant-based probiotic drink (Sharma et al., 2021). “Probiotic” in the strict sense, though, means a microbe shown to benefit health in people, and kanji hasn’t been tested in human trials. Enjoy it as a live, low-sugar fermented drink rather than a remedy. It does contain salt, so count it if you’re watching sodium.
Making It Safely
Natural fermentation is uncontrolled, and researchers working on kanji point out the risk of contamination with pathogens; that is why their work moved to clean ingredients and starter cultures (Kaur et al., 2023). At home, the same principles apply:
- Scrub the carrots, use a clean jar and boiled, cooled water (the study boiled its water too).
- Weigh the salt: about 1.5% of the water’s weight, as in the published method.
- Keep the carrots under the liquid, and stir only with a clean spoon.
- It should taste clearly sour within about 3–5 days at warm room temperature. If you have pH strips, look for 4.0 or lower.
- Discard the whole batch if fuzzy mold grows or it smells rotten rather than sour (NCHFP, USDA). A flat white film (kahm yeast) is different – see our troubleshooting guide.
Without Black Carrots
Black carrots are seasonal and hard to find outside South Asian groceries. Purple carrots that are purple all the way through work best as a substitute; a small piece of beetroot deepens the color. Orange carrots ferment just as well with this method, but the drink will be orange and milder.
More from North India: the yogurt drink lassi and the salted lemon pickle in our guide to achaar. For other fizzy, sour drinks, see fermented drinks beyond kombucha. For orange carrots fermented as a crunchy pickle, see fermented ginger carrots.