Mustard Seed
Also known as: rai, sarson, kadugu
What Mustard Seed is
Much of South Indian cooking starts with a sound: mustard seeds dropped into hot oil, where they split and pop in fast succession — the crackle that opens the tempering for dal, sambar, chutney and a long list of vegetable dishes. In Bengal the same seed anchors panch phoron, the five-seed blend fried together at the start of countless dishes, and across eastern India and Nepal the pressed brown seed yields mustard oil, a cooking fat with a pungency of its own. In Nepal the same seeds temper many achar pickles, and mustard oil is the base fat stirred through them.
The small round seed of several closely related brassicas. Black and brown mustard — Brassica nigra and Brassica juncea — are the sharp, dark seeds Indian cooking calls rai; yellow or white mustard, Sinapis alba, is the larger, milder seed used mainly in pickles and in Western prepared mustard. Black and brown are treated as interchangeable in tempering. The same Brassica juncea plant supplies the greens cooked as sarson ka saag and the seeds pressed for mustard oil, one reason winter fields in Punjab and Bengal turn yellow with its flowers. The Hindi names split by use: rai is the seed in the spice box, sarson the crop in the field, kadugu the Tamil name.
Taste profile
Almost inert as a whole dry seed; everything happens when the coating breaks, in a mortar or in hot oil, releasing sharp, nose-hitting compounds that give mustard its pungency in every cuisine that uses it. Popped correctly, in oil hot enough, the seeds taste nutty and savory — a background warmth rather than a burn — but in oil a few degrees too hot they scorch black and bitter within seconds, and in oil too cool they never pop at all. Ground to a paste with water, brown mustard builds a slow, sinus-clearing heat close to wasabi's. In panch phoron, fried alongside fenugreek, nigella, fennel and cumin, its savory pop is the loudest note.
Forms to buy
- Whole black/brown seed — For tempering; cover the pan — the seeds jump when they pop.
- Yellow/white seed — Milder; for pickles and preserved vegetables rather than tempering.
- Mustard oil — Pressed brown seed, stocked at Indian grocers in Japan; its raw pungency mellows with heat.
Halal note
Mustard seed in every color is a plain seed with no halal concern. Prepared mustard products — pastes, sauces and flavored or infused oils — are where other ingredients enter and labels matter; pure cold-pressed mustard oil is nothing but pressed seed.