Spice guide / Comparisons

Mustard seed vs nigella (kalonji)

Nigella is often sold as ‘black onion seed’ in the UK. It is not mustard, and it is not black cumin.

Culinary differences only. Traditional use is not scientific evidence of a medical effect.

Mustard seed

राई / सरसों · Brassica juncea / Brassica nigra / Sinapis alba

Black, brown, or yellow seeds for tadka and pickles. Allergen: mustard.

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Nigella

कलौंजी · Nigella sativa

Small black seeds (kalonji), not black cumin.

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Flavour and kitchen job

Mustard pops in hot oil for South Indian and Bengali tadka. Nigella is onion-like, used on naan and in some pickles and nigella-tempered vegetables.

When to use which

  • Mustard seed for sambar, lemon rice, poha, and Bengali fish.
  • Nigella on breads, in panch phoron, and some pickles.

If the seed pops aggressively in oil, you probably have mustard. Kalonji is quieter.

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