Ingredient

Coriander

Coriander is the only common plant where the leaf and the seed are treated as entirely separate spices, and reasonably so — they taste nothing alike. The leaf is citrus and soapy-green; the seed is warm, orange-peel-like and faintly sweet. Recipes that say "coriander" without saying which are a genuine hazard.

Why some people taste soap

A significant minority of people find coriander leaf tastes strongly of soap, and this is a genuine difference in perception rather than fussiness. It is associated with variation in olfactory receptor genes, particularly one involved in detecting certain aldehydes — the same family of compounds found in some soaps.

The proportion varies markedly between populations, and it is much higher in some than others. For somebody who experiences it, no amount of exposure or good cooking makes coriander pleasant.

The practical consequence is that coriander leaf should be offered separately where possible rather than stirred through, and that a cook should ask. It is one of the few ingredients where a strong dislike has a physical basis.

The four parts

Leaf

Bright, citrus, green. Added off the heat at the very end — it collapses and loses everything within seconds of cooking.

Stalk

Stronger than the leaf and more heat-tolerant. Chop finely and add early, into a curry base or a stir-fry.

Root

Intense, earthy, deeper. Foundational in Thai cooking, pounded into curry pastes with garlic and white pepper. Sold with the roots on at Asian greengrocers.

Seed

A warm, citrussy, sweet spice, entirely different from the leaf. Toasted and ground for curries, and used whole in pickling.

Cilantro

The North American name for the leaf. Same plant.

Using each part

• Leaf, at the end, scattered over a curry, a soup, a taco or a noodle bowl. Never cooked.
• Stalks, at the start, chopped fine into an onion base or a stir-fry, where they take heat well.
• Root, pounded, in a Thai curry paste or a marinade with garlic, white pepper and fish sauce.
• Seed, toasted whole then ground, in a curry powder or spice blend. Toasting matters — it changes the flavour completely.
• Seed, whole, in a pickling brine or a braise.
• Green coriander chutney, blitzed with green chilli, lime, ginger and a little sugar.
• Whole bunches in a Persian or Georgian dish where herbs are used by the handful rather than the sprig.

Buying and keeping it

1. Buy it with the roots on where you can — an Asian greengrocer usually has it, a supermarket usually does not.
2. Cut the roots off, wash them well, and freeze them. They keep indefinitely and are hard to buy.
3. Stand the bunch in water in the fridge like a bouquet, loosely bagged.
4. Wash and dry the leaves only when you use them.
5. Chop the stalks separately from the leaves and keep them apart, since they go into the pan at different times.
6. Freeze surplus leaf blitzed with a little oil in an ice-cube tray. It is not the same as fresh but it is far better than dried.

Common questions